Biological Anthropology Lecture Notes
Biological Anthropology Lecture Notes 2414
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Modern Bio Test 1 05192014 Chapter 1 Life on Earth Outline 0 Levels of life 0 What are some properties of living things 0 Introduction to evolution 0 Introduction to classi cation Levels of Life 0 Atom 0 Ex Hydrogen H Oxygen 0 Carbon C 0 Molecule 0 Ex H20 Water and C6H1206 Glucose Cell 0 Combination of molecules 0 Smallest unit of life 0 Names of some singlecelled organisms Bacteria A cell is the smallest unit of life 0 Plant cell 0 1 Has a nucleus 0 2 Cell membrane a gate that surrounds the cell to let things in and out nutrients and waste 0 3 Cell Wall holds everything in 0 Bacterial cell 0 1 Does not have a nucleus 0 2 Plasma membrane a gate that surrounds the cell to let things in and out nutrients and waste 0 3 Cell wall holds everything in Levels of life 0 They slowly become more complex 0 Each lower level includes the properties of the higher levels 0 Tissue group of cells with same function 0 Ex Skin 0 Organ many tissues together 0 Ex Heart lungs Organ system multiple organs 0 Ex Circulatory system Levels of life Multicellular organism Individual composed of many cells 0 Ex You 0 Population and species 0 Population members of species within an area 0 Species a group of similar interbreeding animals 0 Community Two or more populations of different species in an area 0 Ecosystem community with its nonliving surroundings 0 Ex Community rocks streams Biosphere entire surface of the Earth Properties of Living things 0 1 Organized structure 0 Composed of cells 0 2 Maintain homeostasis 0 Maintain constant body temperature Ex sweating when you re working out o 3 Metabolism o Consume food produce energy excrete waste 0 4 Growth o Grow in size number of cells increase Ex nger nails and hair always grow 0 5 Reproduction 0 Produce offspring of same type pass on parents genes 0 6 Response to stimuli or adaptations to the environment 0 Rapidly pull your hand away form a hot stove while yelping o 7 Ability to evolve o Populations of organisms evolve in response to the environment INDIVIDUALS DON T EVOVLE POPULATIONS EVOLVE Evolution The Unifying theory of Biology 0 Comments about the picture on the slide 0 Incremental changes 0 The man gets bigger 0 Few similarities 0 Many differences from apes to modern day man Where do these modi cations occur 0 In the genetic makeup of an organism Genetic makeup hereditary information contained in DNA 0 Every organisms DNA is unique 0 This is copied replicated and passed on to their offspring What does DNA look like 0 Each color represents a different molecule Arrangement of these molecules determines the genetic code genes 0 Code is unique for each of us 0 Changes in these molecules or their arrangement results in variations 0 Mutations Mutations 0 Changes in genetic code mutations alter the informational content of DNA Mutations arise from a number of sources 0 Irradiation UV rays Xrays etc o Occasionally arise from copying mistakes during DNA replication 0 Mutations are very rare Are all mutations bad 0 Many are neutral 0 No observable change or changes is not harmful or bene cial Some are harmful 0 Ex cystic brosis sickle cell anemia Genome analysis services like 23 and use these changes in DNA sequence to determine if an individual carrier for a certain condition 0 99 for your DNA to be analyzed Mutations and evolution 0 Preexisting mutations result in variations within a population 0 These mutations are essentials to the process of natural selection 0 Natural selection is an accepted mechanism for evolution 0 Proposed by Charles Darwin and AR Wallace What is Natural Selection 0 Certain individuals in a population survive and reproduce better than others in a given environment 0 Pass on their traits genes to their offspring o Overtime more and more individuals will have these genes 0 The genetic makeup of the entire population will changeevoution Natural selection selects for preexisting mutations within a population 0 Natural selection 0 Does not create mutations 0 Does not have a predetermined outcome 0 Simply selects for the best version of an individual at that time for that environment What happens when conditions change 0 No way to know the exact outcome o If there are members in the population with bene cial preexisting mutations they will be selected for 0 These individuals will grow and reproduce If these are no bene cial preexisting mutations the species may be headedforexUncUon 0 Ex the wooly mammoth 0 Let s look at an example of evolution in humans Lactose tolerance in humans Lactose is the dominate sugar found in milk 0 Most babies are able to digest milk 0 They have and express the actase gene that allows them to digest lactose o The enzyme is turned off in most adults 0 Only 35 of adults are lactose tolerant Up until 10000 years ago adults could not digest lactose o What change How did humans develop lactose tolerance Around 1000 years ago humans started to breed cattle Some of these humans had a mutation in the actase gene 0 Gene was expressed past infancy into adulthood 0 Before this mutation became common milk had to be fermented before consumption 0 Cheese yogurt have reduced lactose and lesser nutrients than milk How did humans develop lactose tolerance 0 During a famine milk was consumed in high quantities 0 Individuals that could digest milk were better able to survive famines 0 Their numbers increased as they reproduced o The actase gene mutation was passed on to their offspring o The famine selectedfor a preexisting mutation o THERE IS NO PREDETERMINED OUTCOME 0 Ex we can t tell right now if we will have wisdom teeth in the future 0 What would happen in the absence of a selective pressure January 22 2014 How are organisms classi ed 0 Organisms fall into 3 domains Bacteria Achaea Eurkarya 2 Domains of life Bacteria and Achaea are prokaryotes Eurkarya are eukaryotes 0 Include Fungi Protests Plants Animals Prokaryotes vs Eukaryotes Bacteria and Achaea are prokaryotes Prokaryote before nucleus Some common features of prokaryotes o No nucleus chromosome is not bound by a membrane 0 No organelles Ex Chloroplasts mitochondria Eukaryote true nucleus Some common features of eukaryotes 0 Contain a nucleus chromosome contained within a membrane 0 Contain organelles specialized membranebound compartments inside the cell 0 Usually larger than prokaryotes 0 Most are multicellular Chapter 14 Principles of Evolution How did evolutionary thought evolve Evolution is accepted theory for modern scientists Evolutionary thought has not always been around 0 At least as old as Greek philosophersboth Plato and Aristotle wrote about evolutionary ideas 0 Believed species were xed 0 Main ideas evolution were not widely accepted until after Charles Darwin published 0n the Origin ofSpecies in 1859 What observations contributed to new ideas on evolution 0 By the 1800 s preDarwin 3 pieces of evidence for evolution had become clear 0 1 Vast numbers of new but similar species 0 2 Geological evidence of Earth s age 0 3 Fossils showing changes over time 1 Observation of vast but similar species Explorations revealed vast numbers of new species 0 Each area had its own distinctive set of species 0 Indicates species are not xed 0 Patterns were found 0 Species near each other were more similar than species that were farther apart 2 Evidence of Earth s age 0 Geology provided evidence for Earth s age 0 Found that the Earth is very old 45 billion years 0 Plenty of time for species to change 3 Discovery of fossils Fossils preserved remains or traces of dead organism o Remains of bones wood shells or impressions left in mud o Fossils provide evidence that life has changed over time Rocks are stacked in layers containing fossils Scientists observed that new rock overlaid older rock 0 The oldest fossils are in the deepest layers and the youngest or most recent fossils near the top 0 These 3 pieces of evidence indicated that species were evolving changing over plenty of time 0 Evolution become clear but not how it worked 0 How What drives this change among species Theories began to arise 0 1st major attempt at an explanation Jean Baptiste Lamarck 17441829 Lamarck s explanation 1 Organisms evolved because they inherited acquired characterizes o Giraffes were able to stretch their necks to reach leaves on high trees all the offspring inherited these necks o If you speak 5 languages your children ill be born with the ability to speak these 5 languages as well 0 Children born to individuals with muscular bodies will have unnaturally large arms at birth 0 2 Also proposed law of use and disuse o Organisms are modi ed during their lifetime through use or disuse of different party s 0 These modi cations are passed to offspring Lamarck couldn t explain how this might work 0 He was shunned but his ideas inspired others Evolutionary Theories 0 Then came Charles Darwin and Alfred Russell Wallace 0 Independently both came up with the same explanation for evolution 0 Neither was taken seriously until Darwin nally published a book 0 0n the Origin of Species by Means of Natural Selection 1859 How did Darwin and Wallace come up with their mechanism for evolution 0 Darwin and Wallace were naturalists o Traveled extensively studying plants and animals 0 Observed some species differ in only a few traits Darwin s nches in the Galapagos island 0 Beak size and shape varies with habitat Few more factors leading to Darwin and Wallace s mechanism for evolution 0 Darwin and Wallace 0 Knew that fossils showed a trend of increasing complexity 0 Were aware that the Earth is extremely old 0 With all of these observations before them they postulated 0 Evolution was driven by natural selection How does natural selection work 0 Darwin and Wallace proposed that 4 postulates accounted for the mechanism underlying evolution 0 If their proposal is correct each of these 4 things must exist in order for evolution to occur 1 Variability in a population 2 Inheritance 3 Reproductive success 4 Natural selection Postulate 1 Individual members of a population differ form each other in many respects variability within a population 0 Population the members of a species in an area 0 In other words all organism in a population have unique varying characters 0 They are not all identical 0 Have small differences in DNA 0 Postulate 2 At least some of the variation can be passed form parents of offspring inheritance 0 At the time genes and heredity were not understood but it was clear that offspring resembled parents 0 Postulate 3 In each generation some individuals survives and reproduce successfully but some do not 0 Many more individuals are born than survive 0 Some individuals have more offspring than others reproductive success 0 Postulate 4 Individuals with advantageous traits survive longest and leave the most offspring 0 Process known as natural selection o In the competition to survive and reproduce winners are determined not by chance but by the traits they possess 0 quotSurvival of the fittest Natural Selection 0 Mutation creates variation in the population 0 Unfavorable mutations selected against Reproduction and mutations occur 0 Favorable mutations more likely to survive 0 Continue to reproduce Natural Selection modi es populations over time 0 Natural selection acts in individuals within a population live and reproduce or don t 0 However it is the population that changes over time 0 An individual cannot evolve but a population can 0 Evolution does not result in a perfect organism it results an organism that is quotbetter than the alternatives at the timequot What evidence do we have to conclude that evolution has occurred 0 Natural selection is a theory of evolution 0 What evidence exists to support this theory 0 4 main lines of evidence 0 1 Fossils 0 2 Comparative anatomy o 3 Embryology o 4 Biochemistrygenetics 1 Fossils 0 Provide evidence of evolutionary change over time o Fossils of ancient species tend to be simpler in former than modern species 0 Series of fossil have been found showing the evolution of body structures over time 0 Suggest that new species evolved from a replace previous species 0 One series reveals that modern whales evolved form landdwelling ancestors 2 Comparative Anatomy 0 Provides evidence of descent with modi cation 0 Comparing the bodies of different species reveals similarities that 0 Can only be explained by shared ancestry 0 Could only result form evolutionary change during descent form a common ancestor 0 Comparison of homologous and vestigial structures Homologous Structures 0 Ex Bird and mammalian forelimbs 0 Contain the same set of bones inherited form a common ancestor 0 Through natural selection these ancestral bones have been modi ed in different animals 0 Structures that have the same evolutionary origin despites their current appearance or functionhomologous structures Vestigial Structures 0 Structures that have nonessential function Remnants of structures inherited from common ancestors 0 Wings in an ostrich o Hind leg bones in whales and snakes o Wisdom teeth tail bone body hair in humans 3 Embryological Similarities All vertebrate embryos resemble one another in their early development 0 Fish humans mice turtles chickens pigs 0 All these embryos show gill slits and a tail early in development 0 Some keep them sh while some don t humans 0 Why do all these diverse animals have the same traits as embryos 0 Shared ancestry o All these animals have the genes for gill slitstails some express them through adulthood and some don t 0 All embryos looks the same such as lemurs pigs and humans January 27 2014 4 Biochemical and genetic evidence 0 All organisms use the following process 0 DNA genes 0 Information in DNA is read and converted to RNA 0 Same inform is them used to make proteins 0 Proteinsbuiding blocks of life 0 We have many lines of evidence showing evolution has occurred 0 Organisms show similarities based on shared ancestry 0 At the same time organism have modi ed over time 0 Why do we attribute this evolution of population to natural selection 0 Ex Some bug spray some are resistance The more you use the more the bug spray will become resistant because the bugs will adapt to it 0 Ex Breading animals picking what kind of dog you want to make Instead of letting nature place it s course we are making the traits apparent 1 Arti cial Selection 0 Arti cial Selection selective breeding to produce plants and animals that possess desirable traits 0 Modern dogs are descended form wolves o In only a few thousand years humans arti cially selected for all breeds of modern dogs 0 Plants have been bred through arti cial selection as well 2 Observations in nature Guppies in Trinidad 2 kinds 0 Bright colored males Preferred by females Easily spotted by predators Abundant in areas lacking predators o Duller males Not as lucky with the ladies Not easily seen by predators Abundant in areas with predators What is the agent of natural selection 0 Predators because they are selectively eating the brightly colored guppies vs the duller colored guppies o The female guppies mating with the colored guppies vs the duller colored guppies Human as Agents of Natural Selection Ex insecticideresistant roaches In Florida the insecticide Combat was successfully used to kill roaches A few roaches had a rare mutation that caused them to dislike the attractant bait in Combat 0 The roaches that did not eat Combat bred successfully and mutation spread throughout the population Ex Use of quotRoundup readyquot crops has selected for herbicide resistant weeds 3 Scienti c Experiments Example the anole lizard experiment Lizards were originally form an island with thicklybranched trees 0 Had long legs so they could move around easily Small groups of these lizards were moved to 15 small island with thinly branched bushes no trees 0 New habitat for these lizards Check on the lizards after 14 years 0 So generations will pass and the mutations can happen After 14 years comparisons were made between lizards on the new island and original island 0 Lizards on all 14 new islands had shorter thinner legs Natural selection favored individuals with shorter thinner legs because they were 0 Able to move better across the thinner vegetation o Able to escape predators betterfaster 0 Thus more shorterlegged lizards survived to pass on their genes for shorter legs Natural Selection Acts on Preexisting Random Variations 1 Chance mutations produce variations that are selected for by natural selection 0 Female mating preferences do not create brightlycolored male guppies 0 Use of Combat does not create insecticide resistant roaches 2 o Darwin s nches with varying body and beak size Chapter 15 How Populations Evolve How Are Populations Genes and Evolution Related 0 Evolution the change over time in the characteristics of a population 0 Different characteristics arise because of genetic variation within a population 0 Genetic variations occur at the levels of genes What are genes 0 Genes sections of DNA that gives an organismal of its traits 0 An individual contains one unique set of genes 0 Prokaryotes have one copy of every gene haploid o Eukaryotes have two copies of every gene one form mom one form dad diploid What are genes 0 For most genes there are multiple forms alleles 0 Ex eye color Alleles blue brown green hazel etc o A gene may have form one to hundreds of versionsalleles Genotype vs Phenotype Genotype the alleles that an organism contains in its DNA the genetic makeup 0 Ex Brown eyes allele blue eyes allele Phenotype how those alleles are expressed what is seen 0 Ex Brown eyes What determines the phenotype Homozygous genotype 2 of the same allele one form mom one from dad 0 Ex Genotype brown eyes allele brown eyes allele Phenotype brown eyes 0 Same type of allele form each parent no choice to be made for phenotype Heterozygous genotype 2 different alleles One from mom one from dad 2 different types of alleles form each parent only one is expressed as a phenotype Brown eye allele is dominant Observed phenotype Blue eye allele is recessive not observed as phenotype Eye Color 0 Assume 4 alleles brown hazel green blue 0 Dark colors are dominate over light colored alleles You have 2 alleles for eye color in any commination of the 4 above 0 Homozygous or heterozygous Homozygous alleles for eye color 0 When the 2 alleles are the same homozygous there is no dominate or recessive allele to determine the phenotype Heterozygous alleles are a whole different story Gene pool and allele frequency 0 Gene pool all the genes in all the individual of a population 0 All the alleles of all the genes in a population Allele Frequencies the amount of particular allele in a population Gene pool and allele frequency 0 Gene pool a population of 230 students contains 460 alleles coding for eye color 0 137 have brown eyes What is the allele frequency for the brown color alleles 1 A population of 137 browneye students contains alleles encoding eye color 0 A 137 o B 274 o 2 What is the allele frequency of the brown allele in this population of 137 students 0 A 137137 0 B 173274 you want to know how often the browneyed allele shows up 0 C 274274 o Allele Frequency the number of times the allele shows up in the heterozygous population and the homozygous population X2 Relationship between allele frequencies and evolution 0 Evolution the change of allele frequencies within a population over generations 0 This is due to natural selection 0 If allele frequencies change form one generation to the next population is evolving o If allele frequencies do not change from generation to generation the population is not evolving What causes the allele frequencies to change in population 0 1 Mutations o 2 Gene ow 0 3 A small population size 0 4 Nonrandom mating sexual selection 0 5 Natural selection 0 All changes in alee frequencyevoution 1 Mutations Mutationschanges in the DNA sequence 0 Can occur naturally during mistakes made during the DNA replication or due to exposure to chemicalsradiation o A mutation in the gametes sperm or egg may be passed on to offspring 0 Can cause new alleles that may be bene cial harmful or neutral determined by environment Humans have 25000 genes 50000 aees o Mutation rate is about 12 mutationsnewborn 2 Gene Flow 0 Gene Flow the movement of alleles form one population to another 0 Movement of individuals between populations is common cause of gene ow Alleles can move even if organisms do not 0 Pollen sperm and seeds form owering plants can move and distribute allies 3 A Small Population Size 0 Allele frequencies are most likely to change by chance rather than by mutations 0 Bad luck events that prevent some members of a population from reproducing Results in random changes in allele frequenciesgenetic drift 0 There alter two causes of genetic drift 0 Population bottleneck o The founder effect What is population bottleneck Population bottleneck a drastic reduction in population size brought about a natural catastrophe or overhunting Can rapidly change allele frequencies and reduce genetic variation Example of population bottleneck o The northern elephant seal 0 Hunter almost extinction only 20 elephant seals left 0 A hunting ban allowed the population to increase to 30000 0 Biochemical analysis shows northern elephant seals are now almost geneUcaHyidenUcal The lack of genetic variation leave them little exibility to evolve if environmental circumstances change January 29 2014 Founder Effect Founder Effect A small number of individuals the founders leave a large population and establish a new isolated population 0 By chance the allele frequencies of the founders may differ from those of the original population Founders establish their own population separate form the original larger population 0 Over time this new population may exhibit allele frequencies that differ form the original population Example of Founder effect 0 An isolation Amish population 0 Allele frequencies of this population are different form the allele frequencies of the general population 0 1 in 200 vs 1 in 1000 carry an allele resulting in the Ellisvan Creveld syndrome 4 Nonrandom Mating o Mating within a population is almost never random 0 Individuals choose mates based on certain traits process known as sexual selection o This bias results in a change in the distribution of genotypes in the population Eg brightly coloreddull colored guppies Animals with bright colors long feathers or ns elaborate antlers usually fare better than duller counterparts 5 Natural selection 0 All genotypes are not equally bene cial 0 Successful organisms are those that have the best adaptations to their particular environment 0 Adaptationscharacteristics that help an individuals survive and reproduce Adaptations arise form the interactions of organisms with both the living and nonliving environment Natural selection and sexual selection can in uence populations in 3 ways 0 1 Direction selection favors individuals with an extremevalues trait 0 Ex Extremely small or big o 2 Stabilizing selection Favors individuals with the average values of a trait 3 Disruptive selection balanced polymorphism or two different virtues favors individuals at both extremes of a trait Balanced polymorphism in humans Hemoglobin is essential molecule required to keep blood oxygenated o A hemoglobin de ciency results in anemia Some individual have a condition called Sickle cell anemia o Caused their red blood cells to appear sickle shaped What causes sickle cell anemia Individuals with normal red blood cells are homozygous for functional hemoglobin HH 0 Individuals with Sickle cell trait are heterozygous Hh 0 One functional copy H 0 One broken copy h 0 Individuals with Sickle cell anemia are homozygous for two broken copies hh can be fatal 0 Why hasn t this allele been eliminated by natural selection Sickle cell anemia and malaria Sickle cell traitanemia is very common in Africa 0 Also common in Africa malaria Malaria parasite infects red blood cells 0 Parasite requires healthy not sickleshaped red blood cells 0 Individuals with Sickle cell traitanemia are resistant to maraia o Hh heterozygotes have passed on the broken copy t their offspring maintaining it in the population 0 H and h alleles are present in the populationbaanced polymorphism Chapter 16 the Origin of Species How do we de ne a species 0 Early De nition species classi ed based upon appearance 0 Despite doing this for 200 years there were some problems Species De nition 0 Biological species concept 0 A group prof interbreeding populations that are reproductively isolated from other such groups 0 A species has individuals that can breed with each other but not with others Limitation of the biological species concept 0 Based on ability to interbreeds can t be used to determine species in organisms that use asexual reproduction o Bacteria yeast A better de nition for species 0 Species populations that evolve independent of each other 0 Remember there has to be gene ow from evolution to occur o If 2 species cannot mate no genes can be introduced form one to another no scope for gene ow How do we keep organisms form mating outside their own species 0 Reproductive isolations can occur in 2 ways 0 1 Premating isolation mechanisms 0 Those that prevent mating between species 5 kinds 0 2 Postdating isolating mechanisms 0 Those that prevent formation of healthy fertile hybrids 3 kinds o For most species two or more isolating mechanisms interact to prevent the formation on fertile offspring Prating Isolating Mechanisms 1 Geooraphical isolation o Prevents interbreeding because populations lives in separate places Not absolute May be able to breed when barrier is removed Successful breeding indicates similar species 0 May allow new species to form 0 2 Ecological isolation o Occurs when species don t mate because they occupy different habitats in the same area These animal do not come into contact with one another Egquot 2 species of garter snakes One lives on land the other water 0 Never meet therefore never mate 0 3 Temporal lsolation o Occurs when species can t interbreed because they breed at different times 0 Trees that pollinate in spring vs summer 0 Animals with seasonal sexual maturity 4 Prematind Isolating Mechanisms o Occurs when species have different courtship and mating ritualsbehaviors 0 Songs and plumage mal songbirds are speciesspeci c 0 Female frogs only respond to male frogs of the same species 0 5 Mechanical Incompatibility o Occurs when species can t mate because their reproductive structures are incompatible o In animals with internal fertilization male and female sex organs may not t together 0 lnsects with differing body plans Snails with lefthanded spiral shells vs righthanded spirals COO Outcome of failed geographical isolation Melting polar ice brought polar bears and frizzy bears closer 0 Their offspring is hybrid quotgrolarquot bear February 3 2014 REVIEW Premating lsolation Mechanisms 1 Geographical different parts of the planet or etc 2 Temporal 3 Mechanical incurability different body parts don t match up can t mate 4 Behavioral different mating ways it makes them unable to mate 5 Ecological different habits between the same area 0 Ex Snake one lives in the water one lives on land They never meet therefore they never mate Postmaing lsolation Mechanisms 1 Gametic Incompatibilitv occurs when sperm from one species can t fertilizes eggs of another 0 Ex Sea urchin sperm cells contain a protein that allows them to bind only to eggs of their own species 0 Gametic incompatibility in plants Prevent the germination of pollen form one species that lands on the ower of another species Different species are pollinated by different insects 2 species of sage one pollinated by butter ies the other by bees 2 Hybrid inability occurs when hybrid offspring fail to survive to maturity 0 Parents mate hybrid offspring die shortly after birth 0 May abort early in development 0 If hybrid survives to adulthood may be unable to reproduce It displays behaviors that are mixtures of the 2 parental types 3 Hybrid infertility occurs when hybrid offspring are sterile or have reduced fertility 0 Hybrid lives but cant reproduce o Mule hybrids a cross between a donkey and a horse 0 Liger hybrids a cross between a lion and tiger o Zebroid hybrid a cross between a horse and a zebra How do new species form Speciation the process by which new species form Speciation depends on o 1 The isolation of populations Prevents gene ow populations remain dissimilar o 2 Genetic divergence of populations must occur Driven by genetic drift or natural selection Speciation can occur in one of two ways Allooatric soeciation populations are geographically separated from each other More common Sympatric speciation populations live in the same geographic area May have very speci c habitats that keep the two populations isolated Speciation is a very slow process 0 How can we tell if speciation has occurred 0 Build evolutionary quottreesquot Rarely many new species may arise in a short period of time o Called Adaptive radiation Adaptive Radiation Occurs when populations of one species invade a variety of new habitats with few competitors Finch colonization of the Galapagos Islands resulted in 13 species Tarweed plant colonization of Hawaiian lsland resulted in 30 species What Causes Extinction Extinction the death of all members of a species 0 At least 999 of all species that ever existed are now extinct Some causes of extinction o 1 Localized distribution 0 2 Overspecialization o 3 Interactions with other species o 4 Habitat change and destruction 1 Localized Destruction 0 Species that live in extremely limited ranges may become extinct if the area is disturbed 0 Ex Just one pond orjust one island Wideranging species would not succumb to local environmental catastrophes 2 Overspecialization Some species develop adaptions that favor survival in a speci c environemntal 0 Ex Karen blue butter y feeds only on blue lupine plant 0 The habitat of the lupine plant has been signi cantly reduced by development 0 Lose of lupine will egad to extinction of the Karner blue butter y 3 Interactions with other species 0 Income with other species one species can be bae to survive 0 Ex 25 million years ago a land bridge formed between north and South America 0 North American species displaced the vast majority f South American species 0 Many become extinct 4 Habitat change and destruction 0 Leading causes of extinction 0 Ex Drought disease re ooding hurricanes volcano eruptions earthquakes etc Humans actives are the primary causes of habitat destruction 0 Ex clearing of tropical rainforeststhe loss of half of all current species over the next 50 years February 12 2014 Chapter 17 The History of Life How Did Life Begin Medieval beliefs re ected the concept of spontaneous generation Spontaneous generation ife arose from nonlife o Maggots were thought to arise from decaying meat 0 Microbes were thought to arise from broth o Mice arise from piles of grain Evidence against spontaneous generation 0 The maggotsrommeat idea was disproved by Francesco Redi in 1668 o No maggots developed when he kept llies away from uncontaminated meat Spontaneous Generation refuted The brothtomicroorganism idea was disproved by Louis Pasteur in the mid18005 Pasteur s experiment disproved spontaneous generation o It doesn t explain how the rst life forms came about Hypothesis small steps that gradually increased in complexity over time o Atomsleoleculesleore and more complex organic moleculescellsife Prebiotic chemical evolution preceded the appearance of the rst life forms on Earth 0 Organic molecules formed rst life arose form combinations of these molecules What was early Earth like 0 No 02 on early Earth 0 But other gases such as hydrogen methane ammonia and water vapor were present 0 02 would not have allowed organic molecules to form 0 02 reacts with other molecules to disrupt chemical bonds 0 High levels of 02 would have prevented the formation of complex organic molecules 0 High amount of UV rays no ozone layer What was early Earth like 0 Lots of volcanic and electrical activity 0 Repeated meteorite strikes 0 Question remains how did we end up with organic molecules Millier and Urey s experiment 0 They mimicked the conditions of early Earth in the lab to see if organic molecules would form 0 Mixed gases that existed in early lifeless environment 0 Added electrical discharge to simulate lightning 0 Simple organic molecules appear after a few days 0 Similar experiments produced portions nucleotides energy molecules 0 All necessary for life Formation of Complex Molecules Simple organic molecules combined to form complex organic molecules 0 Complex molecules became the precursors for the formation of life which took one billion years 0 All of this happened on an oxygenfree Earth 0 Earth formed about 45 billion years ago 0 Life arose 39 to 35 billion years ago 0 Oldest fossils found35 billion years old 0 These were anaerobic prokarvotes that arose in the oceans 0 Some still alive today Anaerobic metabolism does not generate much energy Appearance of Oxygen Eventually some cells evolved ability to use energy of sunlight o Marked the evolution of photosynthesis Photosynthesis releases 02 gas as a byproduct o 02 began accumulating in atmosphere Accumulated 02 began to rust all the iron on Earth 0 When all the iron was converted to rust 02 began to accumulate in the atmosphere Evolution of aerobic metabolism 0 All this accumulated 02 needed to be used up before it caused damage to cells 0 Marked the evolution of aerobic metabolism 0 Humans and other animals use this form of metabolism 0 Cells began to use 02 in energygeneration reactions 0 Helped detoxify the atmosphere of 02 o Generated lost of energy to power cells Prokaryotesleukaryotes Many bacteria aerobes anaerobes photosynthetic 0 Some large some small 0 Larger cells began to prey on the smaller cells 0 Partially digested prey cells remained inside the large cell 0 Over time the smaller bacteria evolved into todays organelles o How did this happen Fig on next slide UnicellularMulticelluar Organisms Now we have singlecell prokaryotes and eukaryotes on Earth 0 Next came multicellular organisms Large size presented a disadvantage 0 Most difficult for 02 and nutrients to get in and waste to get outceHs Solution multicellular organism 0 Big overall can engulf other but individual cells not too big can get nutrients in quickly First Multicellular Organisms Appeared in oceans 12 billion years ago 0 Algae o Photosynthetic organisms Multicellular cells can specialize o Rootlike cells to anchor organism leaflike cells to capture suanht First animals Earliest animal fossils were 1 billion years old Fossils were invertebrate aquatic animals 0 Oldest rock layers had fossils of sponges and jelly sh o Newer rock layers had fossils of worms mollusks and arthropods How Did Life invade Land 0 After more than 3 billion years of watery existence life came ashore 0 1st on shore plants followed by animals 0 Plants moved to more and more shallow waters eventually to water s edge then to the shore First Plants on Land 0 Advantages of being on land 0 Photosynthesis far more effective out of lightabsorbing water 0 Soil has many nutrients seawater low in some nutrients 0 Land was free of predators on plants at the time sea had many predators Animals on Land 2nCI to landanimals invertebrate insects o Invertebrate insects o Exoskeletons gave them improved mobility on land 0 Thrived on land for millions of years 0 Next lobe nned sh crawled onto land 0 Ability to crawl with eshy ns 0 Story 02 in primitive lung 0 Allowed them to move across land if their water source dried Up Animals on Land 0 Amphibians leveled from lobe nned fish 0 Improved improvements in lungs and legs 0 Some amphibians adapted to a drier climate reptiles o Reptilians adaptations to life on land 0 1 Waterproof eggs 0 2 Scaly waterproof skin prevents loss of body water to dry air 0 3 Improved lungs Some small reptiles evolved feathers to keep their bodies insulated birds Reptiles on land 0 As the climate dried reptiles became the dominate land vertebrates Tens of millions of years later climate became more moist and stable 0 Dinosaurs enormous variety 0 Predators planteaters landdwellers seadwellers yers Dinosaurs ourished for more than 150 million years 0 Many small retiles and amphibians still around during this time Appearance of Mammals o Other reptiles mammals 0 Hair insulation 0 Mammary glands nourishing milk for young 0 Uterus live birth possible 0 Earliest mammal fossil 200 million years old 0 Early mammals coexisted with the dinosaurs How Did Humans Evolve o Earliest mammals were primates o Primates tarsiers lemurs monkeys apes and humans Oldest primates fossils 55 million years old Earliest primates fed on fruits and leaves adapted for life in the trees 0 Primates hominines How did humans Evolve Hominess humans and extinct humanlike primates o Oldest hominine fossils are from Africa 0 Comparison of human and ape DNA show that we diverged between 58 million years ago 0 Modern day human is between 160000195000 years old 0 Location of these fossils suggest that Homo sapiens originated in Africa February 17 2014 How has extinction shaped the history of life Evolutionary history has been marked by periods of mass extinction o The most catastrophic mass extinction was 250 million years ago 0 90 of all species on land and sea were wiped out o 2 major causes of mass extinctions 0 Changes in climate 0 Catastrophic events Why did the woolly mammoths become extinct Woolly Mammoths act owers in lush arctic landscape DNA Study shows 0 Samples of permafrost from Arctic tundra that dated to 50000 years ago were found to be rich in pollen from grasses and forbs proteinrich wild owers Fossilized poop samples from woolly mammoths and other animals from the same time period match there permafrost soil composition 1000015000 thousand years ago forbs begin to die off 0 Ice age was ending climate was warmer and wetter 0 Changing climate supported growth of trees and shrubs forbs were not able to grow as well 0 Woolly mammoth food source was disappearing may have contributed to extinction Should we bring back the woolly mammoth Woolly mammoths could be brought back form extinction after scientists discover blood and muscle tissue buried in an ice tomb for 10000 years 0 Hope to nd at least one viable cells Remove nucleolus introduce it into an egg proceed by a female elephant n lmplant the fertilized egg into an elephant hope the pregnancy is successful Alternatively collect stem cells form mammoth blood 0 What about dinosaurs Can we create a Jurassic park Chapter 18 Systematic Why do we need a scienti c naming system Eggplantaborigine Soanum melogena ZucchiniCourgette Curcurbita pepo 0 Common names can be misleading 0 Scienti c names maintain consistency in literature How did the scienti c naming system originate Naming system introduced by the Swedish naturalist Carl von Linee 17071778 0 Called himself Carolus Linnaeus o Linnaeus introduced the twopart scienti c name to all organisms Taxonomybranch of biology that is concerned with naming and classifying organisms Scienti c naming system Formed from the genus species Genus is a group that includes a number of very closely related species 0 Species is a group of organisms that are reproductively isolated from other such groups 0 Individuals belonging to one species are all within the same genus Scienti c naming system 0 No two organisms can have the same scienti c name 0 Names are recognized worldwide 0 Scienti c names are always underlined or italicized o The rst letter of the genus name is always capitalized o The rst letter of the species name is always lowercase 0 Example Homo spanes or Homo sapines How are organisms classi ed 0 Classi cation orientated as a hierarchy of categories Organisms were placed in categories on the basis of resemblance to other species 0 The categories form a nested hierarchy in which each level include all the other levels below it 0 Domain Kingdom Phylum Class Order Family Genus Species Problem with this type of classi cation system 0 Does not re ect evolutionary relatedness 0 Based solely on appearance 0 Darwin published his work in 1859 o All organisms are related by common ancestry o A new classi cation system based on evolutionary relatedness arose Modern Classi cation system Focuses on reconstructing phylogeny o Evolutionary history 0 The science of reconstructing phylogeny is known as systematics Phylogeny involved building of evolutionary quottreesquot 0 Species linked by descent form a common ancestor are put in the same group 0 Such groups are called clades Smaller clades are nested within larger ones An examples of clades with nested hierarchy Each fork represents a speciation event 0 Each line represents a species 0 Colors represent members of the same clade What did we learn from classi cation based on phylogeny Before 1970 all species were divided into two groups 0 Animalia o Plantae included plants bacteria fungi and photosynthetic eukaryotes Clearly oversimpli ed classi cation as more evolutionary relationships became clear Domains of Life 0 A threedomain system more accurately re ects life s history 0 3 domains are Bacteria Archaea and Eukarya System introduced by Carol Woses Groups based on the sequences of a ribosomal RNA gene 0 Gene encodes for a part of ribosome Ribosomes are required to make protein form RNA 0 Gene found in all organisms sequence varies The Tree of Life Bacteria Archae Eukaryote The domain Achaea was a newly discovered they remained undiscovered until Wosese came up with this tree 0 These three split very early in life long before animals and plants evolved Prokaryotes A bacterium An Achaean Why Do Classi cations Change 0 Species designations change when new information is discovered Changes at the top levels of classi cation occur only rarely Changes at species level are more common An Example o It was previously thought that there were only two species of elephant African and Indian 0 Recently the African elephant species has been divided into two species 0 The savannah elephant and the forest elephant DNA sequence comparisons of the savannah and forest elephant reveal they are no more common than lions and tigers Another reason for changes in classi cation Recalls the de nition of speciesbiological species concept 0 Based on sexual reproduction Cannot be applied to organisms that use asexual reproduction 0 Most bacteria Achaea and protests reproduce asexually How are these classi ed 0 Phylogenetic species concept Phylogenetic species concept 0 De nition smallest set of orgasmic that share an ancestor and can be distinguished form other such sets 0 All organisms within the set share certain de ning traits This concepts can be applied to sexually and asexually reproducing organism o It may eventually replace the biological species concept How many species exist Biodiversity is the total number so species in an ecosystem The number of name species is currently about 15 million 0 5 are prokaryotes and protests o 22 are plants and fungi o 73 are animals o It is estimated that 7 million to 10 million spices may exist 0 Between 7000 and 10000 new species are identi ed annually mostly in Tropics 0 Tropical rainforests have the most biodiversity 0 Many unidenti ed species Prokaryotes and counting 5000 prokaryotes and counting As many as 4000 species were identi ed form a single soil sample Considered a bacterium to be a different species if its DNA differed by 30 form other bacteria in the sample How do we nd new species Depends on o Abundance of organism 0 Size of the organism 0 Accessibility 0 The number of researchers searching for them February 19 2014 Chapter 19 the diversity of prokaryotes and viruss Microbes the good 0 Bread 0 Wine 0 Chocolate 0 Coffee 0 Cheese Microbes the bad 0 Potato salad gone bad can make you sick 0 An old peach can hurt you too Microbes the ugly Can cause a lot of infection 0 Less than 1 causes infection 0 The other 99 don t care about humans 0 They are not interested in causing infections 0 They do a lot of good for us Prokaryotes are everywhere 0 Highpressure underground environments 0 Ex Ocean trenches High salt environments 0 Ex Dead Sea Extremely hot environments 0 Ex Hot springs at Yellowstone National Park Extremely cold environments 0 Ex Antarctic sea ice Moderate environments 0 Ex Human body Bacteria Cell Structure Unicellular Structurally simpe no organelles o No nucleus mitochondria chloroplasts Differ in size and shape 0 Very small microscopic in size o 1 micrometer is 110000000 of a meter 0 Range form 02 micrometers 10 micrometers o Largest bacterium is 700 micrometers Bacterial shapes 0 3 common shapes 0 1 Spherical Ex the genus Staphylococcus commonly found on skin soil 0 2 Rodlike Ex E coland the genus Bacillus anthrax o 3 Spiralcorkscrewshaped Ex Genus Helicobacter stomach ulcers Bacterial Cell Structure 0 Bacterial agellum uses to move Capsule protector Pilus uses to exchange DNA between another cell 0 Cell wall outer layer 0 Plasma membrane Cytoplasm Ribosomes in cytoplasm protein 0 DNA in nucleoid Bacteria cell wall Composed of unique molecule called peptidoglycan o Layers 260 of polysaccharides sugars linked by peptides amino acid chains 0 Peptidoglycan makes a meshlike layer around bacteria 0 Some bacteria have a thick peptidoglycan layer 0 Others have a very thin layer of peptidoglycan 0 These have an outer layer of lipids that covers the peptidoglycan layers 0 Thickness of peptidoglycan can used to classify bacteria 0 Gram stain Gram Stain 0 Thick peptidoglycan layer stain Purpe Gram positive 0 Purple rods are anthrax causing bacteria 0 Thin peptidoglycan layer outer lipids stain pink gram negative Pink rods are E coli Genetic makeup of bacteria 0 Single chromosome 0 Genes for all essential functions 0 Also contain plasmids also DNA 0 Separate form chromosome 0 Seen in cytoplasm 0 Genes for accessory functions Ex Antibiotic resistance toxin production etc Some bacteria are motile Use agella singular is agellum to move Extracellular lamentous structure 0 Length is several times longer than cell Flagella can be organized around bacterial cells in many ways 0 Single or multiple 0 One end or spread all over the cell Bacterial classi cation 0 No kingdom or lower classi cation 0 Crude classi cation so far based on other features 0 Shape sphere rod spiral 0 Mode of locomotion agella and their arrangement o Staining properties gram positive negative Bio lms o Bacteria growing together in the form of a lm or layer on a surface CDC estimates 80 of infections are caused by bio lms Many bacteria form lms on surfaces 0 Ex Living and nonliving surfaces 0 Ex Dental plaque 0 Ex Contact lenses catheters Dental Plaque Over 600 species of bacteria in human mouth 0 Some grow as bio lms Some release foulsmelling gases bad breath Excessive bacterial growth results in tooth decay and gum disease 0 Similar bio lms also form on medical implants o Catheters 0 Hip replacement 0 Joint replacements 0 Heart valves 0 Contact lenses How do bio lms form Communicates of slimesecreting bacteria attached to surface 0 Some bacteria secrete sticky layers of polysaccharide or protein slime o Slime allows them to stick to surfaces Infections caused by biofilmforming bacteria are harder to treat 0 1001000 times more resistant to antibiotics and disinfection Endospores Protective structures produced by rodshaped bacteria 0 Allow bacteria to withstand adverse conditions Endospores are resistant even to extremely harsh conditions including boiling for an hour 0 250 million years old endospores produced live bacteria when incubated in a test tube Endospores Endospores are thickly wrapped particles of genetic material and a few proteins Endospores form inside some bacteria under inhospitable environmental conditions Endospores and biological warfare o Anthrax and botulism o Caused b endosporeproducing rod shaped bacteria 0 Can be stored for long periods and survive transport and dispersal methods 0 Once inhaled or ingested bacteria cause damage or death How do bacteria reproduce Binary ssion o A single bacterium replicates its DNA includes plasmids then divides in half 0 Asexual cell division produces identical copies 0 Binary ssion can occur as often as every 20 minutes in some bacteria How do bacteria reproduce Rapid reproductive rate allows for rapid evolution Offspring are clones of parents except for mutations that occur during DNA replication 0 Because replication happens so often bacteria undergo mutations and thus evolve at an incredibly fast pace Conjugation o Prokaryotes may exchange genetic material without reproducing o Conjugation allows for plasmid DNA transfer between donor and recipient 0 Sex pili connect donor to recipient cell drawing the recipient to the donor and forming a bridge Conjugation Produces new genetic combos that may allow bacteria to survive under more conditions Conjugation can even occur between different species of bacteria How do bacteria bene t eukaryotes Many human foods are produced by bacterial action choose yogurt 0 Bacteria in human intestines produce important vitamins 0 Ex vitamins K amp B12 Leafeating animals Ex rabbits cattle can t digest cellulose in plant cell walls 0 Depend on bacteria into their digestive tract to break down the cellulose Bacteria are nature s recyclers Break down waste products and the dead bodies of plants and animals 0 Bacteria derive their energy from the breakdown of these waste products 0 The decomposition frees nutrients for reuse by new life 0 Composting o The recycling of nutrients provides the basis fro continued life on Ea h February 24 2014 Recap bacterial cell structure 0 3 basic shapes 0 Cell wall composed of peptidoglycan Contain a single chromosome 0 May contain plasmids From endospores 0 NOT A REPRODUCTIVE STRUCTURE 0 Form bio lms Bacteria sustain life 0 Most of our atmosphere 78 is nitrogen gas N2 0 All organisms need nitrogen to survive but can t use it in the form of N2 gas 0 Some soil and aquatic bacteria can x nitrogen changing it into a form of plants and animals can use Bacteria growing on plant roots as in nodules harmless tumors Bacteria help cleanup pollution Many humanmade substances are biodegrable by some bacterial species 0 Ex Oileating bacteria were used in clean up the Exxon Valdez oilspill disaster in 1989 o The breakdown of pollutants by living organisms is known as bioremediation o Oileating bacteria being gown in a lab Bacteria infections Diseaseproducing bacteria are called pathogens Humans have battled bacterial diseases throughout history 0 Bubonic plague Black Death killed 100 million people in the 1300 s roughly 13rel of the population in some areas 0 Areas with infected individuals were quartined for 40 day or more Bacterial Infections Tuberculosis is making a comeback in the US 0 Restistant to most known antibiotics Gonorrhea and Syphilis sexually transmitted diseases have reached epidemic proportions around the globe Cholera transmitted in contaminated drinking water 0 Major killer in poorer parts of the world Bacterial infections 0 Common bacterial species can be harmful Streptococcus bacteria 0 Cause tooth decay pneumonia and necrotizing fasciitis quotFlesheating bacterial infection Escherichia coli 0 Common in the human digestive system 0 Some E colare pathogenic 0 Can sometimes be found in undercooked beef from infected cattle 0 Causes intestinal bleeding and can be fatal How do bacteria spread Airborneinhaled 0 Ex anthrax tuberculosis Insect bites from eas mosquitoes 0 Ex typhus plague Contaminated food or water 0 Ex cholera E coli Cuts in the skin 0 Ex staph infection 0 Shared body uids 0 Ex STDs like chlamydia syphilis and gonorrhea How do we treat bacterial infections Antibiotics chemical that stop an essential process inside the bacterial cell 0 First antibiotic in 1928 0 Alexander Fleming discovered Penicillin Many new antibiotic since 0 Emerging antibiotic resistance among bacteria 0 CDC sets threat levels for drugresistant quotsuperbugsquot Antibiotic resistance and you 0 Avoid using products containing triclosan Tricolsan contributes to antibiotic resistance 0 Accumulates in the environment forces bacteria and grow in the presence of this molecule 0 Continuous exposure selects for higher numbers of antibiotic resistant bacteria 0 Always complete your antibiotic course even if you are feeling better 0 Incomplete dosage gives bacteria time to cope wit the antibiotic essentially breeds antibioticresistance Chapter 19 Domain Archea Domain Archaea Less abundant than bacteria 0 Most are anaerobic 0 Oxygen is toxic 0 Exotic environments not all extreme 0 Extreme halophiles salt pools 0 Extreme thermophiles hot acid pools and deepsea vents o Methanogens sewage plants and guts Achaea Convert hydrogen and carbon dioxide to methane gas 0 Methane ammabe and a greenhouse gas 0 Methane in mines o Responsible for explosions in mines How do Archaea compare to bacteria 0 Both are unicellular Bacteria have peptidoglycan archaeal cell walls do not 0 Archaea have different cell membrane lipids than bacteria Archaea cellular proteins are similar to those in eukaryotes No pathogenic Archaea identi ed so far Chapter 19 Viruses Viroids and Prions Are viruses alive 0 Recall properties of living things Organized structure Respond to stimuli Homeostasis Metabolism to produce energy Growth Reproduction 0 Ability to evolve Are viruses alive 0 Opinion varies OOOOOO o Alive once inside a host cell viral nucleic acids become active and the virus replicates 0 Not alive viruses are inert outside of a host 0 VIRUSUS CAN REPDOCUE AND EVOVLE De ning Virus characteristics 0 Not a cell 0 No cell membrane cytoplasm or organelles 0 Not part of Bacteria Achaea or Eukaryote 0 Very small Between 0502 microns De ning Virus Characteristics Hereditary material is either DNA or RNA 0 Surrounded by a layer of protein called capsid Some virus shave an additional layer made of lipids outside the capsid 0 Multiply inside host using host machinery February 26 2014 Viruses are parasites Recall viruses have no metabolism 0 Cannot make their own proteins energy 0 Lack the ability to replicate their DNARNA Viruses hijack host cells 0 Inject their DNARNA into host cells 0 Host cell is now virus producing factory Virus replication 0 Only occurs inside the host cell 0 Many virus particles are made inside one host cell 0 Host cell bursts open to release these particles into environment 0 Infect new host cells Viruses infect speci c host cells 0 Cold virus cells along the membranes of the respiratory tract Rabies virus nerve cells Measles virus skin cells 0 HIV a speci c white blood cell type eventually causing AIDS Viruses can sometimes jump species Mutations may allow a virus to use multiple hosts 0 HIV humans and apes Rabies humans and other mammals H1N1quotswine uquot humans and pigs H5N1quotavian uquot humans and birds Very easily spread among birds now humans are starting to get more than 50 of humans that contract it die Viruses and cancer 0 Some viruses are capable of inducing tumors in animals 0 10 of cancers are known to be virusinduced Viruses hide within cells so are hard to detect 0 Can hide quietly for years then become active such as Herpes HIV and hepatitis Treatment of viral infections Antibiotics target metabolism 0 Ineffective against viruses 0 Viruses use host metabolism 0 Antibiotics are useless for treatment of viral infections Antiviral Drugs 0 Targets differences in virus vs host How can you avoid a viral infection 0 Avoid exposure to infected hosts or contaminated surfaces Immune system 000 o Feveryour body s way of ghting the virus 0 Immunity from previous infection 0 Vaccination exposure to virus inactivated or portion of virus How do vaccines work How vaccines work 0 1 The surface of the microorganism is covered with proteins These proteins antigens are what antibodies can bind to o 2 A dead or inactive form of the pathogen is used to prepare the vaccine The vaccine contains the antigens from the pathogens 0 3 Antibodies are produced by white blood cells 0 4 Antibodies bind to the antigens in the vaccine 0 5 If your body becomes infect with a microorganism that causes the disease to which the vaccine has been produced 0 6 Your immune system quickly produces lost of antibodies 0 7 Which bind to the antigens proteins on the surface killing it Viroids o Viroid consists only of single stranded RNA 0 Lack capsid o No protein no DNA 0 lnfects plants 0 Avocado sun blotch o Cucumber pale fruit disease 0 Potato spindle tuber disease Pdons Prion infectious proteins that lack nucleic acids DNARNA 0 Human o Kuru fatal degenerative disease Crutzfeldt Jakob diseases CJD o Livestock 0 Bovine spongiform encephalopathy Mad cow disease Scrapie Differences 0 Virus DNA and RNA lipids no domain not living reproduce inside a host and evolve Virod RNA no lipids no domain not living reproduce inside a host and evolve Prions Proteins no lipids no domain not living reproduce inside a host and evolve Chapter20 The Diversity of Protists 3 Domains of life 0 Protists anything that is not a plant animal or fungus What are protists Unicellulareukaryotes 0 Few are multicellular Microscopic in size 0 Some are larger 0 Aggregates of unicellular organism About 60000 described species 0 Can be terrestrial or aquatic Modes of nutrition 0 3 main types 0 1 lngest food heterotrophic Ex protozoa o 2 Absorb nutrients form their surroundings heterotrophic Ex protozoa o 3 Photosynthesis autotrophic Ex algae 1 Protists that ingest food 0 Usually predators Some use pseudopods false feet to engulf prey Pseudopods are created by extending the cell membrane to surround and engulf prey Video on TRACS o Other predatory protists create tiny currents by beating their cilia o Cilia are all over the outside of the protest o Beating of the cilia also helps them move 0 Currents sweep food particles into mouthlike openings in the cell 0 Food is contained n a membranesurrounded food vacuole for digestion 2 Protists that absorb nutrients from their surroundings 2 types 0 1 Freeliving types in the soil that decompose organic dead matter 0 2 Parasites that live inside the bodies of other organisms sometimes harming the host Human animal and plant parasites 3 Autotrophic protists algae Found in oceans lakes and ponds Photosynthesis takes place within chloroplasts Reproduction Most reproduce asexually 0 Use mitotic division 0 Some reproduce sexually Sexual reproduction in protists 0 Two individuals no genders exchange genetic material to form an offspring o Offspring in genetically different form either parent 0 Very rare 0 Crowded environments or low nutrient environments Protists and you Pros Photosynthetic marine protists algae most bene cial They capture solar energy and make it available to the other organisms into the ecosystem 0 They release oxygen gas 0 Serve as a food source o Seaweed o Plankton for ocean animals Agar is a gelatinous substance produced by algae 0 Vegetarian substitute for gelatin Thickener forjellies ice creams toothpaste paint cosmetics Used to solidify culture medium for microbiology Biofuels Protists and you Cons Many are human parasites Also cause plant diseases 0 Marine protists cause ecological damage 0 Release toxins that can accumulate to harmful levels in coastal areas Human parasites o 1 Trichomonas is the STI infecting the urinary and reproductive tracts 2 Trypanosoma affects human blood causing quotAfrican sleeping sicknessquot o Leads to ulike symptoms followed by neurological dysfunction and then death 0 3 Pasmodium is spread by mosquitoes and causes malaria 0 Causes over 1 million deaths annually 0 4 Parasitic amoebas can cause dysentery Hard to treat illnesses cause by protists because they are euka ryotes too 0 We need to nd ways to kill them without harming our own cells NOT TESTED OVER THE LAST FEW SLIDES OF THIS CHAPTER March 24 2014 Animal Diversity 1 lnvertebrates Chapter 23 Recap Phylum Proifera sponges o Phylum Cnidarian jelly sh hydra Phylum Arthropododa insects arachnids myriads and crustaceans o Exoskeleton o Jointed legs 0 Segmented body Phylum Arthropod The nervous system ahs a brain and nerves that run throughout the whole body 0 Finely coordinated movement and complex behavior Possess welldeveloped sensory structures 0 Ex compound eyes 0 Social insects bees ants Phylum Arthropod lnsects 0 Only invertebrates that can y Undergo a process called metamorphosis o Radical change from a juvenile body form to an adult body 0 Juvenile form is usually wormlike called larva Phylum Arthropod lnsects Bombardier beetle Produces a hot toxic spray Protects beetle form ants and other predators Phylum Mollusca Second most diverse animals after arthropods o Are found in aquatic or moist terrestrial habitats 0 Includes snails clams squid octopus Moist muscular body without a skeleton Most have a hard calcium carbonate shell 0 Have large head with complex brain eyes 0 Octopus squid o Bilateral symmetry 0 Highly developed sensory systems Are capable of learning Tentacles to grab and tear prey Deadly Octopus Blue ringed octopus Deadliest sea creature Blue rings appear when provoked o Venom can kill humans 0 No known cure Phylum Echinodermata o Exclusively marine Sea urchins star sh sea cucumbers sand dollars sea lilies o Echino spinesbumps dermskin o Hedgehog skin Phylum Echinodermata o Larvae exhibit bilateral symmetry adults show how radial symmetry classi ed as bilateral Possess an endoskeleton internal skeleton 0 Have a primitive nervous system with no distinct brain Phylum Echinodermata Many are able to regenerate lost body parts 0 Ex A sea star arm with party of the central body attached is able to form a whole animal Bene ts of invertebrates Food sources crabs shrimp insects etc Pollinators bees butter ies etc Decomposers beetles millipedes ants slugs etc Bene ts of invertebrates 0 Medical uses 0 Leaches used in reconstructive surgery to remove excess blood and promote blood ow 0 Blow y maggots can rid wounds and ulcers of dead and dying tissue that interferes with healing or cause infection Bene ts of invertebrates Some sponges contain chemicals useful to humans 0 The drug spongistain is used to treat fungal infections that are common in AIDS patients 0 Eribulin is a chemical that may treat breast cancer that comes form the Halichondria sponge Invertebrates and humans Harm Flatworms Ex Tapeworms may be present in improperly cooked beef pork or sh Invertebrates and Humans Harm Roundworms 0 Ex Hookworm larvae bore into human feet and travel to the intestine where they cause continuous bleeding 0 Ex Heartworms can be transmitted to cats and dogs by the bite of an infected mosquito Invertebrates and Humans Harm Some arachnids such as spiders and scorpions inject paralyzing venom into prey o Sting or bite especially dangerous to those with allergies o Ticks and mosquitoes can spread diseases such as Lyme disease and malaria March 26 2014 Animal Diversity Vertebrates Chapter 24 Key Features of chordates Size Varies 0 From microscopic sea squirts 0 To whales more than 100 feet long 0 4 key structures 0 1 Flexible supporting rod the notochord o 2 Hollow dorsal nerve cord 3 Gill groves or slits o o 4 Postanal tail Chordate features 0 1 Notochords o A stiff exible rod extending the length of the body 0 May only appear during embryonic development Provides support for body and muscles 0 2 Nerve Cord o Hollow tubular cord 0 Lies above the digestive tract Front part of the nerve cord forms the brain 0 3 Gill slits or grooves 0 Located in pharynx behind the mouth Eventually forms gills May only appear as grooves during embryonic stages 0 4 Postanal tail 0 The tail extends past eh anus 0 Contains muscle tissue 0 May only appear during embryonic stages humans Humans are Chordates Key chordate features are best seen during embryonic development 0 Later we lose our notochord gill grooves and tail 0 Only the nerve cord is retained in adult humans 5weekold human embryo 1 cm long 0 Tail will disappear completely but gill grooves contribute to formation of the jaw The 2 Chordate Clades 1 Lanaceltes Invertebrates 2 Tunicates Invertebrates 3 Craniates 0 Both invertebrates and vertebrates Tunicates Sea Squirts Invertebrate marine lterfeeders The larvae are motile and exhibit all chordate features 0 Adults are usually stationary Sea Squirts 0 Get their name form their ability to squirt water when disturbed Water food particles enter through opening on top left 0 Food is trapped in basketlike pharynx 0 Water is expelled through opening on top right Lancelets Invertebrate marine lterfeeders Small shlike retain all 4 chordate features as adults 0 Live halfburied in the sand with only the front end of their bodies expose 0 Food particles are drawn into the mouth by tentacles Craniates Include all chordates with a skull enclosing a brain 0 This group includes 0 1 Hag shes invertebrates o 2 Vertebrates embryonic notochords is replaced by a vertebral column Hag shes Lack a true backbone 0 Have a rudimentary skull Lack jaws but have teeth 0 Feed primarily on worms but will also eat dead sh Secrete massive quantities of slime as a defense against predators o Slime balls of the sea Often sold as eel ell leather Vertebrate Adaptations 0 Internal skeleton can grow and repair itself 0 Allows for greater size and mobility M allows animals to eat a much wider range of food sources Paired appendages help stabilize movement ns legs wings 0 Brain complexity allow animals to perceive the environment in more detail and allows better response to stimuli What Are the Major Groups of Vertebrates 1 Lampreys 2 Cartilagionous shes sharks and rays 0 3 Ray nned shes tuna salmon trout o 4 Lobe nned shes lung sh 5 Amphibians frogs toads salamanders 6 Reptiles snakes lizards crocodiles birds 0 7 Mammals kangaroos platypus bats humans Lamprey Live in both fresh and salt water Jawless like hag shes 0 Have a rounded sucker that surrounds the moth Some parasitize sh 0 A lamprey will attach to a host with its suckerlike mouth o It has teeth on its tongue with are used to make a hole in the sh body to suck blood and body uids Invasive sh found in the Great lakes Cartilaginous Fishes Marine animals include sharks and rays 0 Have jaws and cartilaginous skeleton Their body is protected by leathery skin embedded with tiny scales Rays Sharks Rows of razorsharp teeth allow sharks to feed on large prey 0 Marine mammals crabs large sh etc 0 Some sharks feed by ltering plankton Most sharks avoid humans but some can be dangerous 0 In 2011 there was 75 documented attacks worldwide Many shark species are endangered due to over shing Flat bodies animals with wingshaped ns Thin tails 0 Some have a spine near the tail for defense 0 Others produce an electric current Bottom dwellers Feed on invertebrates Ray ned shes Most diverse and abundant vertebrates 0 Includes regular sh and eels Bony sh found in freshwater and marine habitats Distinguished by the structure of their ns 0 Formed by webs of skin supported by bony spines Worldwide human food source Populations of almost all ray nned sh species have declined drastically due to over shing Many sh have been reduced to 10 of their original populations snzes 0 Many in danger of extinction tuna bass snapper Lobe nned shes Example lung shes Have eshy round ns that contain bones surrounded by a tick layer of muscle lobe nned o Lung sh have gills and lungs 0 Can survive when water dries up by burrowing into mud Some of these ns help drag sh over land 0 Gave rise to the 1st vertebrates on land amphibians March 31 2014 Amphibians Include frogs toads and salamanders Amphibian is Greek for quotdouble lifequot 0 Begin life adapted to water 0 Ex tadpoles have gills Mature into semiterrestrial adults with lungs 0 Most adults respire through lungs and moist skin 0 Skin must be kept moist to avoid desiccation when out of water 0 1st to transition to land but still have aquatic egg or larval stages 0 Con ned to moist watery environments 0 Externalfertilization Reptiles Include lizards snakes alligators turtles crocodiles and birds Adapted to life on land 0 Have welldeveloped lungs o No gillsmoist skin required 0 Welldeveloped skeleton allows for movement on land Key Reptilian Adaptations for life on land 0 1 Tough scalv skin protects the body and resists water loss 0 2 Internal fertilization male deposits sperm insides the female s body 0 3 Shelled amniotic egg encases the embryo in a liquid lled membrane preventing it from drying out on land Birds A distinctive group of reptiles o Distinguished from other reptiles by feathers highly specialized reptilian body scales Modern birds retain scales on their legs 0 Left over from shared ancestry with the rest of the reptiles Birds are adapted for ight Feathers provide and lift and control as well as insulation Hollow bones reduce the weight of the skeleton The nervous system provides coordination and balance Have an acute eyesight Birds are warmblooded endothermic unlike all other reptiles which are coldblooded exothermic Mammals Named for milkproducing mammary glands 0 Females use these to nourish their young Warmblooded with high metabolic rates Have bodies covered with hairfun o Protects and insulates Most have legs designed for running rather than crawling Have sweat scent and sebaceous oilproducing glands 0 Not found in other vertebrates The mammalian brain is highly developed 0 Mammals have unparalleled curiosity and learning ability 0 Allows them to alter their behavior based on experience learning other animals can do this but mammals are best 0 Have extended parental care after birth Mammalian groups Mammals are subdivided into 3 groups 0 1 Monotremes lay eggs 0 2 Marsupials live young o 3 Placental mammals live young Monotremes egglaying mammals Only 3 species 0 Platypus o 2 species of spiny anteater echidnas All are found only in Australia and New Guinea 0 Lay leathery eggs rather than giving birth to live young 0 The newly hatched young are nourished from milk secreted by the mother Marsupilas Opossums koalas kangaroos wallabies wombats and the Tasmania devil Embryos begin develop in the uterus of the female 0 Young born at a very immature stage and must crawl to a nipple to completely develop 0 In most postbirth development is completed in a protective pouch Placental mammals Most mammal species are placental mammals o The uterus contains a placenta that provides gas nutrient and waste exchange between mother and embryo 0 Young are retained in the uterus for their entire embryonic development Placental Mammals Inhabit land air and sea 0 Highly diverse includes bats moles whales seals monkeys cheetahs humans etc Rodents account for 40 of all mammal species 0 Rats mice squirrels hamsters porcupines etc 20 of mammalian species are bats 0 Only mammals to have evolved wings and ight Many bats are predators and hung frogs sh or insects Nocturnal spend the day in caves trees or under a bridge Bats in Texas o The largest urban population of bats live under the Congress Avenue Bridge in Austin which crosses over Lady Bird Lake quotMexican FreeTailed Batquot 0 Depending on the month anywhere between 750000 and 15 million bats can be seen ying out each night at dusk specially in the summer 0 The world s largest population of bats in Bracken Cave just outsides of San Antonio 0 Also Mexican FreeTailed Bats 0 Pregnant females gather there to birth their young About 20 million bats at any given time o It takes hours for all to y out of the cave each night 0 Ap l7m2014 Chapter 25 Animal Behavior Behavior terms 0 Behavior any observable activity of living animal 0 Ethology The Study of animal behavior 0 There are 2 forms of behavior 0 lnnate usually genetically based nature 0 Learned Usually environmentbased nurture lnnate Behavior 0 Can be performed without prior experience 0 The behavior appears even if the animal has never been taught this behavior before 0 These are performed to completion the rst time an animal at o The right age and o The correct motivational state encounters a particular stimulus Example of lnnate Behavior ln Humans Hunger humans are able to communicate their hunger state from a very young age Grasp re ex very strong in babies 0 Response to stimuli withdrawing your hand when you touch a hot object Example if innate behavior in birds 0 Female cuckoo birds lay their eggs in the nests of other bird species crows 0 Chicks are raised by the unwitting adoptive parents 0 Shortly after the cuckoo egg hatches the chick will shove the nest owner s eggs out of the nest o Eliminates competition for food 0 Innate behavior 0 Chick s have not been taught this behavior 0 Born with this instinct Learned Behavior Learned behaviors require experience 0 Learning the capacity to make changes in behavior on the basis of expenence Ex The process by which a human learns language 0 Ex A cougar teaching her babies how to hunt Types of Learned Behaviors o 1 Habituation o 2 Conditioning 0 A Classical conditioning o B Trialanderror conditioning Operant conditioning 3 Insight learning 1 Habituation Habituation a decline in response to a repeated stimulus o Prevents an animal form wasting its energy and attention or irrelevant stimuli 0 Even the simplest animals show this behavior 0 Ex Sea anemone Habituation in Humans Those living in urban areas are habituated to sounds of traf c construction sirens airplanes 0 Those in the countryrural areas are habituated to sounds of insects frogs birds etc o If someone moves form one habitat to the other initially these sounds are a problem over time individuals get habituated to them 2a Classical Conditioning 0 Condition a learned association between a stimulus and a response 0 Classical conditioning an animal learns to perform a response normally caused by one stimulus to a new stimulus Example Pavlov s dogs 2b Trialanderror learning 0 New and appropriate responses to stimuli are acquired through expenence Examples 0 Learning which foods taste good and bad 0 Learning not to touch a hot stove o More examples Learning not to cram for a test Learning not to play with dangerous insects Learning not to drink excessively Trailanderror learning in a toad Toad is stung by a bee when it tries to eat it Avoids all insects that resembles bees Toad is presented with a dragon y insect that doesn t look like a bee immediately east it 0 Response is speci c to bees Operant Conditioning 0 A learning technique often used to train animals 0 Animals to learn behaviors to receive a reward or to avoid punishment 0 Examples 0 Going to work getting paid reward 0 Breaking the law getting arrested punishment 0 More examples Potty training rewarding them with treats or taking the treat away Teacher giving stickers to students Training a animal to sit 3 Insight learning 0 Insight learning problem solving without trail and error 0 In certain situations animals can solve problems suddenly without prior experience 0 Done by mentally manipulating concepts 0 Requires high level of intelligence 0 Ex Making tools 0 Humans and chimpanzees do this Example of insight learning 0 A hungry chimpanzee without any previous training can stack boxes to reach a banana suspended form the ceiling 0 Examples 0 Fixing your WiFi 0 Fixing things at home 0 Walking around a pillar that is in you way 0 A chimp taking a wire and turning into a key in order to escape from its cage Innate and Learned Behavior Behaviors are classi ed as innate or learned to help scientists that study them 0 Animal behavior is usually a combination of both types Innate behaviors can be modi ed by learned behaviors 0 Ex you withdraw your hand when you touch a hot object innate response 0 You learned that a stove is hot so you shouldn t touch it Example of innate behavior modi ed by learned behavior Newly hatched gull chicks peck for food at a red spot on its parents beak innate Within a few days the chick come to recognize their own parents as they mature 0 Learn to only peck for food form their own parents and not other objects are a red spot Learning is limited by innate constraints 0 Animals can only acquire appropriate behaviors 0 Example A robin is born with the ability 0 sing innate 0 Can only learn songs of its own species the songs of other species cannot be learned 0 Songs of other species are not useful therefore cannot be learned 0 Imprinting is one type of behavior that illustrates this concept Imprinting 0 An animal s nervous system is rigidly programmed to learn a certain behavior 0 Occurs at a particular time during development Period is called sensitive period 0 Birds such as geese ducks and chickens 0 Chicks learn to follow the object they encounter the most during their sensitive period the mother bird 0 Chicks have imprinted on the mother bird 0 In the laboratory these birds may imprint on a toy train or other moving object o Goslings imprinting on the father of ethology ls behavior determined by genes or the environment Probably both 0 One example Migratory birds that must be able to navigate the night sky 0 Role of the environment 0 Chicks denied access to the night sky are unable to orient themselves at night 0 Environmental cues were missing during development 0 What about the genetic component Example Migrating birds 0 Na39ive migrating birds hatched only months earlier travel properly form on location to another without any previous experience 0 The birds thus appear to be born with the ability to migrate o It must be in their genes 0 Migration is combination of genes and environment How Do Animals Communicate 0 Communication a signal by one organism that causes another organism to change its behavior 0 Exchange of information 0 There are many ways in which animals communicate 1 Visual displays 2 Sound 3 Chemicals 4 Touch 1 Visual Displays 0 Most effective over short distance 0 Speci c movements or static images convey a message 2 Communication by sound 0 Effective over longer distances 0 Different messages can be conveyed by variations in sound patter volume and pitch 0 Can attract predators Sheep can tell each other apart and recognize their lambs by the different sounds they produce 0 Dogs bark or whine to communicate different emotions 3 Chemical Communication 0 Chemical messages persist for long periods but are hard to vary 0 Chemicals produced by individuals can in uence the behavior of other members of the same species 0 These chemicals are called pheromones Pheromones Pheromones are typically not detectable by other species 0 Do not attract predators Can act as a signpost persisting over time and marking an animal s boundades Examples of pheromoneinduced behavior Pheromones can cause immediate changes in the behavior of the detecting animal 0 Ex Foraging termites that discover food lay a trail of pheromones from the food to the nest Other termites immediately follow the trail Pheromones can cause physiologicachanges in the detecting animal 0 Ex A queen honeybee produces a pheromone quotqueen substancequot 0 Prevents other females in the hive form becoming sexually mature Tricking Lamprey with their Pheromones Invasive sh in the Great Lakes 0 Use pheromones to attract mates and draw them to good spawning areas 0 Females lay up to 60000 eggs at a time o Spawning is usually upstream Synthetically produced pheromones are added to streams with lamprey traps o Attracts lamprey and prevents them from reentering lake system More uses for pheromones A similar approach is used to combat insect pests o Traps are baited with sex attractant pheromones o Traps won t kill bene cial insects Humans and pheromones Humans may respond to pheromones Ex The menstrual cycles of female roommates and close friends tend to become synchronized 0 Possible that this synchronization is due to pheromones passed between women 0 The actual molecules that cause effects on menstrual synchronization remain unknown as does their function Humans and Pheromones Other types of human pheromones have been suggested but none have been discovered Humans lack the speci c sensory system found in all other animals that detects chemical signals 4 Touch 0 Include kissing nuzzling patting petting and grooming etc Helps establish and maintain social bonds 0 Especially in human and other primates 0 Touch is important to human development and wellbeing 0 Also cements the bound between parents and offspring Touch is also a part of sexual communication Apnl92014 Chapter 26 Population Growth and Regulation Some Terms 0 Ecosystem all living biotic and nonliving abiotic components of a de ned area 0 Pond ocean island forest campus 0 Population all members of a species living within an ecosystem o Squirrels birds people 0 Community group of interacting populations Biosphere a ecosystems on Earth Ecology study of the relationships between biotic and abiotic components of the environment Some facts about populations 0 Some populations remain stable over time 0 Others change in either a o Yearly cyclical pattern OR o Sporadically What causes these changes in population size and composition Factors that affect population size 0 1 Births 0 Increase population size 0 2 Deaths 0 Decreases populations size The difference between births and deaths natural increase in population 0 3 Immigration 0 Increase populating size 0 4 Emigration o Decrease populating size The difference between immigration and emigration net migration of population Populations grow when 0 Natural increase net migration is positive 0 More births and immigration Populations shrink when 0 Natural increase net migration is negative 0 More deaths and emigration 0 Birth and death rates primarily in uence population sizes 2 Factors impact birth and death rates Opposing interactions between 0 1 Biotic potential Theoretical maximum increase in a populating ldealy maximum birth rate minimum death rate 0 2 Environment resistance Limit on population growth due to environmental factors Available resources predators parasites natural disasters 0 If environmental resistance is low populations can grow rapidly Birth rates are consistently higher than death rates Results in exponential grow in population size 0 On average each individual produces more than 1 offspring in its lifetime 0 Graph of population size over time produces a Jshaped curve What is a Jshaped curve Represents an exponentially growing population 0 Every individual in the population has the capacity to produce offspring 0 Usually more than one Factors that affect the biotic potential 1 Age at which the organism reproduces 2 Frequency of reproduction 3 Average number of offspring produced each time 4 Length of reductive life span 5 The death rate of individuals must remain less than the birth rate total population size will continue to increase may take longen How is population growth regulated Exponential growth can occur only under ideal conditions 0 Ideal conditions are not really observed in nature Populations usually undergo quotboomandbustquot cycles 0 Photosynthetic bacteria 0 Growth depends on available nutrients water temperature rainfall Temporary exponential growth can occur when environmental resistance is low Seen in populations that don t experience boomandbust cycles 0 Sudden increase in resources food 0 Decrease in predators o Invasion of new favorable habitat invasive species Ex animal species protected from hunting have grown exponentially since the bans have been put in place Environmental resistance helps limit population growth Any environment can sustain population growth only up to a certain point 0 Availability of space nutrients other resources Carrvind capacitv the maximum population size that can be sustain by an ecosystem If the increase in population size is above the carrying capacity growth with halt 0 Once resources are restored growth can resume 2 factors generate environmental resistance 1 Density dependent o More efficient at limiting population size with an increase in population density 0 2 Density independent 0 Limit populating size regardless of population density DensHydependent Occurs due to o 1 Predation o 2 Parasitism o 3 Competition Predation Predation becomes important as prey populations grow 0 Helps control prey population size Predator populations often grow as their prey become more abundant The number of offspring produced is determined by the abundance of prey 0 Ex snowy owls produce many offspring when their prey is abundant 0 Ex Little to no offspring in the absence of prey Parasitism Parasites live inside a host feeding on it o Harm the host sometimes kill the host 0 Most parasites cannot travel long distances 0 Spread better among dense populations 0 In uence population size by 0 Weakening their hosts 0 Making them more susceptible to death from other causes Competition 0 Competition for limited resources 0 Food water nutrients nesting sites access to sunlight etc 0 Two major forms of competition o lntraspeci c competition between individuals of the same species 0 lnterspeci c competition between individual soft different species 0 More on this in the next lecture Densityindependent limitation of population size 0 Habitat destruction by human activities 0 Use of pesticides Natural disasters 0 All limit population growth regardless of population density Densityindependent and density dependent factors interact to regulate population size 0 Ex Caribou Weakened by hunger and attacked by parasites 0 Both density dependent More lively to be killed by an exceptionally cold winter 0 Densityindependent Ap l142014 Chapter 27 Community Interactions Why study community interactions 0 Community a group of interacting populations in an ecosystem o Biotic and abiotic components 0 Why are community interactions important 0 Control population size densitydependent control 0 Maintain resources in balance with population size 0 Act as agents of natural selection coevolution Types of community interactions 0 Outcomes of interactions between organisms A and B o 1 Competition 0 Both A amp B harmed o 2 Predations of A on B o A bene ts B is harmed 3 Parasitism of A on B o A bene ts B is harmed o 4 Mutualism 0 Both A amp B bene t Ecological Niche Each species occupies a unique ecological niche 0 Habitat role of the organism in that ecosystem Habitat includes 0 Physical environment required for that organism to grow and breed successfully o Nutrients climate water soil quality sunshine etc 0 Role of the organism in that ecosystem o Photosynthetic or heterotroph 0 Preferred food source plantsanimalsinsectsbacteria Competition and ecological niche No two spices over occupy the exact same ecological niche within the same community 0 Can have shared aspects 0 The up overlap between the ecological niches of 2 species up the competition 0 lnterspeci c competition 0 Both competing species are harmed o Reduces availability of a limited resource for both species So what happens during interspeci c competition 0 Resource partitioning o Adaption that reduces interspecies competition 0 2 species coevolve to occupy smaller niches than they would without competitionboth are harmed o Allows individuals to grow and reproduce more efficiently less competition What about intraspeci c competition 0 Competition between members of the same species 0 More intense than interspeci c competition 0 Limits amount of resources 0 Selects for individuals who are better equipped to acquire the limited resource Predation Interaction between predator and prey o Predators must feed and prey has to avoid being eaten Constantly exert selective pressures on one another 0 Counteracting behaviors by predators and prey o Camou age 0 Bright colors 0 Mimicry 0 Chemical warfare Counteracting behavior Bats predator and moths prey Bats use echolocation to locate their prey o Emit short pulses of high pitched sound 0 Sound echoes as it bounces back from an object prey Moths have evolved ears that are sensitive to the pitches used by bats 0 Fly erratically when they hear a bat o Bats counteract this response by changing the frequency of their sound pluses Camou age Helps conceal both predator and prey Disguises that resemble their surroundings 0 Leaves tree bark twigs Camou aged animals usually remain motionless 0 To hid from a predator 0 To ambush unsuspecting prey Some plants resemble rocks to avoid predation Bright colors 0 Used to warn off predators Indicative of poisontoxinsbad taste 0 Poison dart frog Mimicry Members of one species have evolved to resemble another species 0 Two or more distasteful species may each bene t form shared warning coloration pattern Predators need only experience one distasteful species to learned to avoid all with that color pattern 0 Example toxic monarch and viceroy butter ies Startle mimicry Some spices have evolved color patterns that resemble the eyes of a much larger animal 0 When a predator gets close the prey ashes its eyespots startling the predator o Prey can escape Chemical warfare Toxins produces the spiders scorpions snakes beetles o Deter predators o Paralyze prey Plants produce distasteful and toxic chemicals to deter herbivores 0 At least one insect feeds on every toxic plant 0 lnsects use the plant toxin to defend against their own predators o Milkweed and monarch caterpillar Parasitism Parasites live inside a host o Harm the host 0 Sometimes kill the host Bene cial to the parasites to keep its host alive 0 Generally smaller than the host 0 Tapeworm eas ticks bacteria viruses protests Parasitehost interactions act as agents of natural sectioning one another Parasitehost interactions Malarial parasite protest infects humans red blood cells 0 Parasite exerts a strong selective pressure on regions where malaria is common 0 Individuals with distorted sickleshaped red blood cells are resistant to malaria 0 2040 of people living in malariainfested regions have Sickle cell disease 0 One normal alleleone broken allele 0 2 broken copies of the allele can cause anemia fatal Mutualism Both interacting species bene t 0 Many are longterm symbiotic associations 0 1 Lichenfungi photosynthetic algaebacteria o Fungi provide shelter photosynthetic partner provides food Examples of mutualism o 2 Bacteria in your intestines o Bacteria have a comfortable place to live while synthesizing your vitamin K for you 0 3 Nitrogen xing bacteria that live on roots of legumes soy alfalfa o Bacteria provide that plant with N get food in return How do keystone species impact community structure 0 Keystone species a particular species that play a major role in determining community structure 0 Play a major role regardless of its abundance 0 Holds the community together o If you remove the keystone species from a community 0 Normal community interactions are altered 0 Changes the relative abundance of other species in the community Examples of a keystone species Lobster off the Canadian east coast feed on sea urchin Overfishing of lobster resulted in an increase in the sea urchin population 0 Sea urchin feed on certain algae o Algal population was drastically reduced 0 Left large surfaces of rock exposed that were previously occupied by thriving communities 0 Keystone species need to be identi ed and protected to prevent collapse of communities Ap l162014 Chapter 28How do ecosLstems work Flow of energy and nutrients through ecosystems o 1 Nutrients constantly cycle and recycle within and among ecosystems 0 Carbon nitrogen water phosphorus etc o 2 Energy moves through ecosystems in a continuous oneway ow 0 Many kinds of energy light heart chemical bonds 0 One way form sun to Earth to through an ecosystem to lost back to the atmosphere as heat 0 Energy is NOT recycled must constantly be replenished by the sun How does energy ow through ecosystem Sun converts hydrogen into helium o This transforms a small amount of matter into enormous quantities of energy 0 A tiny fraction of this energy reaches Earth in the form of electromagnetic waves 0 Includes heat light and ultraviolet UV energy What happens to energy reaching Earth 0 Most of the energy re ected by the atmosphere clouds and Earth s surface 0 Only 1 of the energy get through and is available to power life Photosynthetic organisms plants can capture this solar energy 0 Capture only a tiny fraction 0 Life on Earth is supported by less than 03 of the energy reaching Earth from the sun How do plants trap this energy 0 Plants capture it through photosynthesis Photosynthetic autotrophic organisms capture the energy 0 Plants algae protests some prokaryotes Sunlight energy is used to make sugars which fuel the energy needs of all organisms on Earth What happens to this energy trapped during photosynthesis Once energy is captured it ows through communities within an ecosystem The quantity of producers in an ecosystem determines how much life it can support 0 Measured as Net primary production NPP o The energy that products store and make available to other members of the community NPP values of various ecosystems High NPP tropical rain forests oceans near land 0 Anywhere that can support a lot of life 0 Low NPP deserts lack of water open oceans limited sunlight access 0 Anywhere that can t support much life Role of organisms in an ecosystem Producers autotrophs 0 Make their own food using solar energy Consumersheterotrophs o Organisms that cannot photosynthesize 0 They acquire energy and nutrients form molecules in the bodies of other organisms o Producers and consumers are organized into trophic levels Energy is passed form one trophic level to the next Trophic levels 0 1st trophic level 0 ProducersPhotosynthetic o Autotrophic energy form sun 2nol trophic level 0 Primary consumers o Herbivores that feed directly on producers eg mice zebras grasshoppers etc 3rCI trophic evessecondary consumers o Carnivores that eat herbivores primary consumers 4th trophic level tertiary consumers o Carnivores that eat carnivores secondary consumers 0 Spiders hawks cheetahs are higherlevel consumers 5th trophic evequaternary consumers 0 These are usually apex predators at the top of the food chain Complexity in ecosystems A species can belong to more than 1 trophic level at ta time especially omnivores o Eg Bears might eat berries 2nCI level 0 Bears might eat a moose calf 3rd level 0 Bears might heat foxes or coyotes 4th level 0 Food for thought 0 How would you classify a Venus ytrap that caught and digested a ladybug o Ladybugs may eat other insects plants even fungi Food Webs vs Food chains 0 Food chains are oversimpli ed 0 Not representative of actual ecosystems where feeding is not Hnear A food web shows the actual feeding relationships in a community 0 Better represent relationships in a community o This includes many interconnecting food chains What about the nutrients trapped in dead organisms Detritus feeders and decomposers complete the cycle 0 Convert the bodies of dead organisms into simple molecules 0 C02 water and minerals Form a vital link in the nutrient cycles of ecosystems by recycling these nutrients What would happen if decomposers and detritus feeders were absent Detritus feeders and decomposers Detritus feeders 0 Live on dead organic matter Other organisms fallen leaves fruit and wastes a Ex Mites earthworms protests worms centipedes some insects snails and vultures Decomposers o Secrete exoenzymes Absorb some nutrients leave the rest for other organisms o Primarily consists of fungi and bacteria Energy ow through ecosystems Only about 10 of available energy transfers form one trophic level to the next 0 Very inefficient Hawk less 10 Robin less 10 Grasshopper less 10 Grass maximum energy Energy ow is not very efficient Energy is lost at each level because of the metabolic activates of the organisms o Hopping ying A big chunk of energy was lost as heat o 10 law the net energy transfer between trophic levels is roughly 10 efficient o Organisms in higher trophic levels must eat several times their body weight to meet their energy needs Chapter 29 Earth39s Diverse Ecosystems What factors determine the distribution of life on Earth 0 4 things 0 1 Nutrients to build tissue 0 2 Energy to conduct metabolic activities 0 3 Availability of liquid water for metabolic reactions to occur 0 4 Favorable temperatures to carry out all these functions 0 Resources are unevenly distributed 0 Limits the types of organisms that can exists in each ecosystem Distribution of life on Earth Organisms with the right adaptations inhabit each ecosystem 0 Example Desert regions lack water 0 Plants have adaptations that help them conserve water 0 Example Polar regions have freezing temperatures 0 Animals regulate blood ow in their legs to prevent frostbit Practical implications of 10 law 0 We can feed more people directly on grain than on meat form animals fed on grain Cattle farming 18 of all greenhouse gases 0 More than all transformation on Earth combined 0 Reducing meat consumption will reduce our ecological footprint 0 Big push toward vegetablebased diets among environmentalists and humanitarians Biological magni cation Organisms in higher trophic levels accumulate toxic substances theyingest o Toxins become concentrated in the bodies of longlived animal humans bioogica magni cation Example Mercury taken up by producers can accumulate and become highly concentrated in carnivores such as sword sh Nutrient cycles 0 Unlike sunlight nutrients do not ow down onto Earth in a steady stream form above 0 Recycling is essential Nutrients are stored in reservoirs 0 Usually abiotic environment 0 Example carbon is stored in carbon dioxide and fossil fuels coal oil natural gas 0 Carbon must cycle form abiotic to biotic components of the ecosystem Carbon cycle 0 C02 trapped by photosynthesis introduces C to Biotic component 0 Producers to consumers to detritus feeders and decomposers to back into the atmosphere 0 C02 is also released during respiration Combustion of fossil fuels burning forests add C02 back into the atmosphere 0 Back to the abiotic component What happens when humans disrupt the carbon cycle Combustion of fossil fuels releases almost 10 billion tons of C02 into the atmosphere each year 0 About half of this carbon is absorbed into the oceans plants and soil 0 The other half remains in the atmosphere Deforestation accounts for 15 of C02 emissions 0 Since 1850 atmospheric C02 has increased by 37 o Exacerbates the greenhouse effect What is the greenhouse effect Sunlight enters the atmosphere 0 1 Some of the energy from sunlight is re ected back into space 0 2 Most of the sunlight reaches Earth and is converted into heat This heat is radiated back into space 0 C02 and several other greenhouse gases methane trap some of this heat in the atmosphere 0 This is a natural process called the greenhouse effect 0 Keeps the Earth warm Greenhouse effect and global warming 0 As greenhouse gas levels rise 0 More heat is retained than the radiated back into space 0 Causes the Earth to warm more than necessary 0 Human activities have ampli ed the natural greenhouse effectglobal warming 0 The decade form 1998 to 2008 is the warmest ever recorded 0 To See What Climate Change Feels Like Go to Texas Nitrogen cycle 0 N gas in the atmosphere largest source of N o Fixed into ammonia by nitrogen xing bacteria 0 Useable form of nitrogen by plants animals 0 Nitrogen xing bacteria may be freeliving in soil or water 0 Others have a symbiotic association with eh roots of leguminous plants 0 Many farmers will rotate crops between legumes and non leguminous crops to improve soil fertility Ammonia returned to soil via dead decomposing organisms Nitrogen cycle cont d o Nitrous oxide from burning of fossil fuels lightning to converted to nitrate in soil 0 Nitrates also accumulate form agricultural runoff 0 Used by producers to make proteins and DNARNA o Producers to consumers to detritus feeders and decomposers to back into the atmosphere by denitrifying bacteria Convert nitrate to nitrogen gas What happens when human disrupts the nitrogen cycle activates Excessive use of nitrogenbased fertilizers o Nitrates leach into soil and accumulate to high amounts 0 Can enter water supply and cause illness in humans Nitrous oxide form fossils fuels combines with water vapor to produces nitrous acid acid rain 0 Damages forests lakes and even buildings and statues Ap l21 2014 Chapter 29 Earth39s Diverse EcosLstem What factors determine the distribution of life on Earth 0 4 things 0 1 Nutrients to build tissue 0 2 Energy to conduct metabolic actives o 3 Availability of liquid water for metabolic reactions to occur 0 4 Favorable temperatures to carry out all these functions 0 Resources are unevenly distributed 0 Limits the types of organisms that can exist in each ecosystem Distribution of life on Earth Organisms with the right adaptations inhabit each ecosystem 0 Example Desert regions lack water 0 Plants have adaptations that help them conserve water 0 Example Polar regions have freezing temperatures 0 Animals regulate blood ow in their legs to prevent frostbite What are biomes Distinct plant and animal communities occur in speci c regions on land and in water 0 Such communities are called biomes o Biomes are named after primary type of plants growing in the region 0 Grasslands deserts tundra etc o What plants grow depends on the amount of rainfall and temperature Tropical rain forests near the equator Central and South America Africa and Southeast Asia 0 Have constant high temperatures and rainfall 0 Warm and evenly moist conditions Tropical rain forests Tropical rain forests are very dense 0 Extremely tall trees up to 150 feet midrange trees and short shadeloving trees 0 Huge woody vines grow up the taller trees Shorter plants have enormous leaves 0 Allows them to trap the low levels of sunlight reaching the forest oor Animal life in the tropical rain forests 0 Most of the animals live in the trees 0 Variety of monkeys birds insects 0 Soil does not have nutrients to support growth of consumers All of the nutrients are trapped in the vegetation Very intense competition for nutrients on the ground Human impact on rain forests An area the size of 15 football elds is destroyed every second in the rainforests 0 Over 50 of the world s rain forests are already gone 0 Trees are cut for lumber 0 Soil does not have nutrients to support agriculture 0 Trees may be burned to release nutrients 0 Heavy rains wash away soil with the nutrients quickly Clearing of rainforest result in 0 Increased C02 levels to contribute the global warming 0 Loss of biodiversity Deserts Deserts are de ned more by their lack of water than by their temperatures 0 Annual rainfall is 10 inches or less 0 They are found on every continent 0 Typically in the rain shadows of major mountain ranges Widely spaced vegetation and large areas of bare ground 0 Annual wild owers race through their life cycle in the brief period of moisture following a storm Desert plant adaptations Cacti 1 Shallow spreading roots that absorb rainwater before it can evaporate from the soil 0 2 Thick stems that store water for use during droughts 3 Modi ed leaves spines 0 Provided protection against predators o Conserve water 0 4 A waterproof waxy coating on stems further reduces water loss Desert animal s adaptions They spend the day in underground burrows coming out only at night 0 Larger animals are depended on permanent water holes during the driest times of the year Smaller animals can get all of the water they need form food and cellular respiration Human impact on deserts Desert soil is stabilized by microbial communities 0 Bacteria algae fungi lichen Form a black crust on soil surface 0 Bind sand particles together absorb water produces nutrients supports seed germination o A single step can kill a 1000year old community 0 Offroad vehicles also contribute to destruction of desert soil 0 Reduces nutrients causes soil erosion o Desertification human activities have resulted in this o The process by which relatively dry droughtprone regions are converted to deserts o Caused by drought coupled with overuse of the land Grasslands Prairie 0 Located in the centers of continents 0 Central North America 0 They have continuous cover of grass and virtually no trees except along rivers o Frequent droughts of the prairies can be tolerated by grasses but not trees Human impact on grasslands Prairie 0 Nearly all tallgrass prairies have been plowed for agriculture 0 Largely con de to protected areas Bison Prairie dogs Bobcats o All endangered due to reaching and growing town boundaries Taiga Largest terrestrial biome on Earth 0 Stretches across North America Scandinavia and Siberia nearly encircling the globe 0 Conditions in the taiga are very harsh 0 Long cold winters and short growing seasons Taiga diversity Conebearing trees are dominant 0 Trees have narrow waxy needles to reduce evaporation during winter 0 Breeding grounds for many of North America s birds 0 Many large mammals Black bears moose deer wolves foxes Human impact on taiga Clearcutting for papermaking and lumber o Contributes to soil erosion reduces soil fertility All the new trees will be of the same age 0 Do you think this is a problem Why TUndra Vast treeess region between the taiga and polar ice cap on the Arctic Ocean 0 The tundra is a quotfreezing desertquot 0 Very little rain 0 Winter temperatures often reach 40 degrees or below fortnight with howling winds 0 Freezing can occur even in summer the growing season lasts just a few weeks 0 The cold climate of the tundra results in permafrost o Permanently frozen layer of soil about 2 feet below the surface 0 THERE ARE ABSOLUTELY NO TREES 0 Because of the extreme cold the brief growing seasons and the permafrost trees cannot survive 0 When the soil thaws in the summer the permafrost prevents water from soaking in Results in the tundra turning into a huge marsh Tundra Diversity 0 Lichen small owers dwarf willows Mosquitoes and other insects during the summer months 0 Support the growth of migrating birds 0 Arctic hares rodents wolves reindeer Human impaction Tundra Very fragile biome because of its short growing season 0 Human impact is localized around oildrilling sites pipelines mines and military bases 0 Climate change is the biggest threat to the tundra 0 Trees are beginning to grow along the southern margin of the tundra Apnl232014 Life in the ocean Aquatic ecosystems can provide abundant water and appropriate temperatures 0 Problem light decreases with depth 0 But nutrients tend to concentrate near the bottom 0 Where nutrients are highest the light leaves are lowest 0 Therefore life in the ocean is concentrated in shallow water where sunlight can penetrate Open ocean Most open ocean life is restricted to the more shallow areas 0 Too deep for plants to anchor elsewhere 0 The food chain in the open oceans is dependent on microscopic phytoplankton Human impact on open oceans o 1 Pollution 0 Main sources of poutiondeiberate dumping by ocean vessels oil spills and agricultural runoff 2 Over shing has caused sh to be harvested in unsustainable numbers 0 Some international efforts are now being made to prevent over shing Wetlands Regions where soil is covered or saturated with water 0 Many aquatic and some terrestrial plant species live here Wetlands act as giant sponges absorbing water and then gradually releasing it into rivers o Safeguards against ood and erosion o Filters water before releasing it into rivers Human impact on Wetlands Wetlands in the US have decreased by about half 0 Drained and lled for agriculture housing and commercial uses 0 Makes water more susceptible to populates reduces wildlife habitat and can increase the severity of oods As a result of recent laws to protect wetlands the rate of loss in the US has declined slightly Coral reefs Complex formations that have accumulated over thousands of years 0 Calcium carbonate skeletons or coral relatives of sea anemones Coral reefs are most abundant in tropical waters 0 quotOcean s rain forestsquot home to more than 90000 known species with many more yet to be identi ed Human impact on coral reefs o Runoff from farming logging and construction carries silt 0 Results in reduced sunlight and oxygen 0 Harms photosynthetic organisms and hinders coral growth 0 When waters become too warm many species die off
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