MSU Biology 1 Class Notes and Study Guides
MSU Biology 1 Class Notes and Study Guides bio 1134
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Bio 111 - Fundamentals of Biology II
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Bio I 11-13-12 Chapter 54: Introduction to Ecology and Biomes Ecology the study of the interactions of organisms and their environment. Includes biotic and abiotic interactions. Biotic interactions between living organisms o Predator and prey Abiotic interactions between living organisms and their environment o Availability of water and sunlight Scale of Ecology Organismal ecology o Physiological ecology adaptations physiological o Behavioral ecology adaptations behavioral Population ecology demographics of a population o Population growth o Species interactions Predation Competition Parasitism o Community ecology Species interactions how we go from separate populations to form a functional community Species richness the number of different species in a community The rainforest compared to the Artic Succession a return to a natural state after some sort of disturbance o Ecosystems ecology Energy flow and nutrient cycles Biotic and abiotic components Trophic levels and food webs Ecological interactions Trophic levels o Primary producers organisms that serve as the base of the food web/chain; convert energy into a usable form. Plants as they carry out photosynthesis o Primary consumers organisms that consume primary producers Herbivores/ plant eaters o Secondary consumers consume primary consumers Carnivores o Scavengers feed on dead or dying organisms; larger animals Vultures Bio I 11-13-12 o Decomposers feed on dead or dying organisms Bacteria and Fungi May include: o Predators o Competitors o Plants o Abiotic factors Effect of abiotic environment Distribution pattern Abundance Factors o Temperature o Wind o Salt concentrations o pH o Water availability Optimal range or niche plants and animals have a range of temperatures, certain concentrations of salt in some organisms. Where you would find them based on factors Abiotic factors Temperature o Most important factor in the distribution of organisms o Exothermic animals “cold blooded” o Endothermic animals “warm blooded” Can regulate body temperature o Plants frost Wind enhances effect of temperature Water Availability all organisms needs water o Plant distribution some need more water, some need less o Animal distribution their distribution is directly linked to plant distribution. (Follow their food) Light o Plant distribution photosynthesis Shade tolerant plants Full sunlight plants Aquatic systems sunlight only goes so far Salinity salt o Animals Freshwater fish hypertonic Marine fish hypotonic Bio I 11-13-12 o Plants o Halophytes pH o Variation Acidic waters Toxins, heavy metals leach into the water. Cause problems for aquatic animals/fish Acid rain caused from the burning of fossil fuels; releases certain toxins into the environment contact with water = acid rain o Rainwater pH 5.6; plants grow well at this pH o If pH drops below that, plants will not grow well; prevent nitrogen fixing Climate and biological communities Climate the prevailing weather pattern in an area (long term) Climate predicts the distribution of plants and animals Greenhouse effect Caused by solar radiation. Energy radiated Atmospheric gases Necessary for life Caused mainly by greenhouse gases; a lot are being released due to human activities o Carbon dioxide o Methane o CFCs Global warming Human activities All greenhouse gases have increased CO2 Anticipated changes in the global climate o Afraid organisms can’t respond fast enough Temperature differentials Temperature determined by the amount of solar energy is being received. Solar radiation Poles versus equator General trend Bio I 11-13-12 Atmospheric circulation Temperature directly effects winds Atmospheric circulation Major biomes Ocean currents Wind and Earth’s rotation Pinwheels Elevation and mountains Elevation effects temperatures o High elevation = low temperatures Mountains o Rain shadow o Mountains close to ocean Seattle Biomes Major areas of land classified by rainfall and temperature 10-23-12 bio I The experiment Monohybrid crossone characteristic/trait P generation (parental) F1 generationoffspring of P generation; hybrids F2 generation Homozygoustrue breeding plant Heterozygous 3:1 phenotypic ratiorefers to outward trait or what it looks like 1:2:1 genotypic ratio 3 important ideas dominant and recessive traits o recessivemasked by dominant trait o blending inheritancemajor idea of inheritance at the time. Ex: dark pink+white=light pink genes and alleles o particulate mechanism o “unit factors”genes/alleles o allelesparticular variant of gene you have o genecharacteristic/trait segregation of alleles o heterozygotes1 dominant/1 recessive o homozygous dominant2 dominant alleles o homozygous recessive2 recessive genotype and phenotype genotype genetic composition; inherited alleles o homozygous 2 copies of some allele o heterozygous 2 alleles (T and t) phenotype o gene expressionwhich allele has an effect punnett square Tt X Tt (crossing 2 heterozygotes) genotype ratio: TT: Tt: tt 1: 2: 1 phenotype ratio: tall: dwarf 3: 1 dihybrid cross looking at 2 genes instead of just one (2 characteristics) law of independent assortmentalleles of different genes sort into gametes independently. (increase genetic variationgood thing!) chromosome theory of inheritance 1. genetic materialcontained on chromosomes 2. replicated and passedDNA replication; meiosis/ sexual reproduction 3. diploid cells 2 sets of chromosomes homologs 4. homologues segregatehomologous chromosomes separate 5. haploid cellsgametes 1 set of chromosomes; during fertilization they fuse to give a diploid offspring law of segregation homologous chromosomes locus the physical location of a gene on a chromosome law of independent assortment meiosis random alignment of homologous chromosomes during o meiosis I (metaphase I) o 2 possible outcomes **true for genes on different chromosomes** sex chromosomes and xlinked inheritance autosomes (122) sex chromosomes (23) o xy system xx female ; xy male xlinked genesfound on X chromosome, but not on Y o “normal” X^H o dz X^hA o hemizygouslacking an allele for a particular gene Chapter 17: Complex Patterns of Inheritance Linkage 2 genes physically close on the same chromosome Discovered by unexpected results in F2 F2 ratio= 15: 1: 1: 4 Crossing Over Violates linkage The exchange of pieces of homologous chromosomes during meiosis F2 o Nonrecombinants did not cross over o Recombinants did cross over Conclusion Genes on the same chromosome tend to be inherited together Crossing over new combos of alleles Crossovers recombinant chromosomes Chapter 22 Origin and History of Life Big Bang 14 billion years ago (BYA) Solar system formed about 4.5 BYA Earth formed about 4.5 BYA Outer layers solidified into rock and oceans formed about 4 BYA Life about 3.54 BYA o First life= simple, single celled prokaryote Origin in 4 overlapping stages 1. Nucleotides and amino acids a. Monomers for macromolecules 2. DNA, RNA, and proteins 3. Membranes 4. Cellular properties History of Life on Earth Geologic time scale o Divided into eons o Further divided into eras and then periods Precambrian= super eon Cambrian explosion occurred right at dividing line between Precambrian and Cambrian. (explosion in diversity) o Every plant and animal we know of evolved after Cambrian explosion o First vertebrates, land animals, and shells appeared. Typically aquatic plants and animals start moving to land. Produce seeds and get first insects o About 100 million years after that, we get reptiles, dinosaurs (dominant animals) and mammals (very small). o About 160 MYA we get our first birds. o First flowers appear on Earth o Hominidshuman like ancestors Diversity of Life 1. Genetic changes 2. Environmental changes o Can allow for new types of organisms evolution o Responsible for many extinctions extinction Mass extinctions o 5 mass extinctions so far. o Major one dinosaurs o Open up new areas for organisms to evolve o Used to divide time lilnes o Scientists think we are in the beginning of the 6 mass extinction because human population is so large, less plants and animals and climate change. Horizontal gene transfer a transfer of genetic material that is a direct transfer Chapter 23 An Introduction to Evolution Biological Evolution A heritable change in the genetic material of a population over many generations. Biological evolution o Microevolution Small scale single gene o Macroevolution Larger scale new species Species a group of related organisms that can interbreed and produce viable offspring. Population a group of members of a species in a certain area. History John Ray first to develop some sort of classification system; about 1600s; first developed species concept Carolus Linnaeus expanded on John Ray’s classification system and discovered hundreds of plants and animals. JeanBaptiste Lamarck noticed that some animals seemed unchanged and others changed over time. (noticed change over time) o Evolving towards perfectionhumans o Believed in inheritance of acquired characteristics (changes that occur in individual can be passed to offspring) Charles Darwin 2 major fields: geology and economics Geology o Uniformitarism Proposed by Hutton and Lyell Recurring eventsslow process Economics o Competition Put forth by Thomas Malthus only a small percentage of any population will survive because of competition. Voyage of the Beagle famous voyage where he formed most of his ideas. Beagle (1831 1836) Galapagos Island famous stop made o Darwin observed unique plants and animals. o Famous thing= Galapagos Island Finches or “Darwin’s finches” o 1840s= theory of natural selection o 1856= started writing The Origin of Species Alfred Wallace o Got wind of Darwin and ideas and came up with his own idea of evolution/natural selection pretty much the same to Darwin’s Darwin’s The Origin of Species Descent with modification o Organisms change over time Chapter 59: Ecosystem Ecology Ecosystem: Ecosystem biotic community and abiotic environment Ecosystems ecology movement of energy and materials through organisms and ecosystems Food webs and energy flow Food chain Trophic level Food web Autotrophs takes inorganic materials and converts them to organic materials. Light or chemical energy to form covalent bonds between carbon molecules. o Primary producers organisms that photosynthesis. (Light) o Chemoautotroph Use energy from inorganic chemicals Heterotrophs Get energy from consuming another organism o Primary consumers o Secondary consumers o Detritivores (feed on detritis, organic material in the process of breaking down) or decomposers Food chain lengths Food chain lengths the number of links. 6 links is the upper limit. Energy transfer Second law of thermodynamics energy lost as heat or waste. Energy transfer through trophic levels Measure the efficiency of consumers o Production efficiency (individual level) Energy incorporated into new biomass (growth) Invertebrates highest efficiency rates: 1040% Vertebrates 10% Fish (ecotherms) 10% Endotherms 12% High efficiency organisms include invertebrates, bacteria, ecotherms, and young organisms. Organisms with relatively low efficiency include vertebrates, adults, and endotherms. o Trophiclevel transfer efficiency Energy at one trophic level incorporated into biomass at the next trophic level. Low efficiency level around 10% Two reasons for why it is low: 1. Undigestible food 2. Lost as heat Pyramid of numbers looking at number of individuals in each trophic level. (Looking at species abundance) o The number of individuals decreases as you go up the trophic level. Inverted pyramids Looking at species abundance o The number increases as you go up the trophic level. Pyramid of biomass Looking at amount of biomass in each trophic level. o As you go up the trophic levels, it decreases. Biomagnification Biomagnification o Chemicals build up in food chains Ex: DDT o Tends to concentrate in tissue o Higher trophic levels Biogeochemical cycles Movements of chemicals through ecosystems o Biological transport mechanisms the absorption and release of elements; take them in and when decomposing, it goes back. o Geological transport mechanisms physical factors: erosion, water movement, etc. moving elements around. o Chemical transport mechanisms weather; rain, snow, wind, etc. moving elements around Phosphorus Cycle Phosphorus cycle ATP, nucleic acids o Plants take phosphate from soil and make phosphorus o Herbivores get phosphorus from eating plants o Carnivores from eating Herbivores o Decomposers return phosphorus back to soil o Leaching and runoff take phosphorus from soil and put it into water o Weathering and erosion phosphorus is taken from rock and put into soil or water making a cycle No atmospheric component Carbon cycle Carbon cycle o Atmosphere o Autotrophs o Plants 1/7 of atmospheric carbon o Carbon reserves ways we can trap the carbon and keep it incorporated in soil, etc. Ex: fossil fuels o Carbon sources Ex: volcano erupting o Steady rise o Global warming Nitrogen cycle Nitrogen cycle 78% o Limiting nutrient 1. Nitrogen fixation bacteria convert nitrogen gas to ammonia/ammonium 2. Nitrification bacterica convert ammonia/ammonium to nitrate 3. Assimilation nitrate becomes assimilated in plants 4. Ammonification converting nitrate back to ammonia/ammonium 5. Denitrification bacteria taking ammonia/ammonium and converting it back into nitrogen gas Human alterations o Fertilizer runoff in water o Excess nitrates in drinking water o Burning fossil fuels releases nitrogen in atmosphere that would not normally be there acid rain Water cycle Water cycle Evaporation and precipitation Chapter 60: Biodiversity and Conservation Biology Biodiversity: Biodiversity can be examined at 3 levels o Genetic diversity amount of genetic variation that occurs within and between populations o Species diversity threatened species are likely to become endangered, endangered species are in danger of extinction o Ecosystem diversity diversity of structure and function within an ecosystem Conservation biology protects biological diversity at all levels Why conserve biodiversity? o Humans depend on plants, animals, and microorganisms for a wide range of food, medicine, and industrial products o Preserve essential services of ecosystems, such as clean air and water o Ethical responsibility to protect what are our only known companions in the universe Economic values o Zea diploperenis, an ancient corn relative, is resistant to many corn viruses and its genes are being used to develop resistant corn o 25% of prescription drugs in the US are derived from plants o Desert pupfishes are models for research on human kidney disease World’s ecosystems worth more than $33 trillion a year How much diversity is needed? How much diversity for proper function? o Diversitystability hypothesis linking diversity and stability suggests a linear correlation between diversity and ecosystem function o Rivet hypothesis species are like rivets with each playing a small critical role o Redundancy hypothesis most species are redundant, they take up space but do not add to diversity, but keystone species are vital to function Tilman experiments seem to support this hypothesis Plots sown with up to 24 species of native prairie plants Results showed again that more diverse plots had increased productivity and used nutrients more efficiently than less diverse ones Frequency of invasive plant species and foliar fungal diseases decreased with increased richness Arthropods species richness increased with plant species richness o Idiosyncratic hypothesis ecosystem Causes of extinction and loss of biodiversity Extinction is a natural process o Average life span of a species in the fossil record is around 4 million years Background extinction is 1 species every 1,000 years May be higher at 1 or 2 every 100 years Biodiversity crisis in the past 100 years, 20 species of mammals and over 40 species of birds have gone extinct. Growth of human population linked to number of extinctions Causes of extinction Introduced species/ invasive species o Introduced species o Invasive species Competition can eliminate local populations; not shown to cause extinction Predation rats, cats, and mongoose account for 43% of recorded bird extinctions Disease 50% of native Hawaiian birds extinct due to avian malaria Direct exploitation o Passenger Pigeon Habitat destruction Climate change o Phenology Loss of genetic diversity o Inbreeding mating among relatives More likely when population small Survivorship of offspring can decline Greater prairie chicken reduced to population with 5 or 6 males, resulted in steady reduction of hatching success, brought in Kansas birds to increase diversity o Genetic drift Random change in allele frequency attributable to chance Allee effect some individuals fail to mate by chance, loss of rare alleles Small isolated populations more prone Can be countered with immigration o Limited mating Effective population size Number of individuals Conservation strategies Habitat conservation focuses on o Megadiversity countries greatest number of species Just 17 countries are home to nearly 70% of all known species Brazil, Indonesia, and Columbia top the list Do not necessarily contain the most unique species 208 mammal species are shared between Peru and Ecuador (part of the 17) o Areas rich in endemic species Endemics found only in a particular place Hot spots have the widest variety of endemic species with at least 1,500 species of vascular plants and lost 70% of original habitat 34 hot spots occupy only 2.3% of Earth’s surface but contain 150,000 endemic plant species (50% of world total) Tropical rain forests are rich in endemics and may receive more attention/ funding at the expenses of other areas o Representative habitats While the Pampas of South Africa does not compare well to the richness or endemics of Reserve design Principles of island biogeography o Wildlife reserves and sanctuaries are islands o The larger area, the greater number of species would be protected o Edge effect o SLOSS debate (single large or several small) single large reserve may be able to preserve a larger population or several smaller ones may contain a broader variety of habitats and a reduced risk to fire or disease Principles of landscape ecology o Examines the spatial arrangement of elements in communities and ecosystems o Link small reserves with biotic corridors or movement corridors o Hedgerows in Europe function as corridors between forest fragments o In China, corridors of habitat link small, adjacent population of giant pandas o Parks are often designed to minimize edge effects so circular parks are preferred over long, skinny parks Economic considerations o Principles of island biogeography and landscape ecology useful o Economic considerations often enter in the choice of areas to preserve o In Africa, several large parks contain sizeable populations Conservation single species approach Indicator species species whose status confirms the overall health of an ecosystem o Corals are good indicators of siltation o Proliferation of the dark variety of the peppered moth has been shown to be a good indicator of air pollution o Polar bears are an indicator for global climate change Umbrella species habitat requirements are so large that protecting them also protects many other species in the same habitats o A Northern spotted owl pair needs 800 hectares of oldgrowth forest for survival and reproduction o To protect Zea diploperennis, the land where it grows was bought and a nature reserve established Flagship species single large or instantly recognizable species o Attractive ad engender public support o American buffalo, giant panda, Florida panther Keystone species species within a community that have a role out of proportion with their abundance o Beaver can completely alter a community by building a dam and flooding an entire river valley o Palm nuts and figs produce fruit during otherwise fruitless times and are critical resources o Not a dominant species one that has a large effect in a community because of its abundance o Gopher tortoises Restoration ecology Restoration ecology o Full or partial repair or replacement of biological habitats and/or their populations that have been damaged o Can restore or rehabilitate a habitat o Can return species to the wild following captive breeding o Bioremediation use of living organisms to detoxify polluted habitats Habitat restoration o 3 basic approaches complete restoration attempt to put back exactly what was there prior to disturbance rehabilitations return habitat to something similar but less than full restoration ecosystem replacement= replaces orginal ecosystem with a different one deciduous forest replaced after mining by grassland Bioremediation o Use of living organisms, usually microbes or plants, to detoxify polluted habitats such as dump sites or oil spills o Some bacteria can detoxify contaminants o Certain plants can accumulate tocins in ther Chapter 56: Population Ecology Populations Population o Definition o Example Population Ecology o Study of populations and how they grow; promote and limit growth o Demography demographic data Birth rate Death rate Age distributions Size of populations Understanding populations Density number of individuals in a given unit of area Quantifying population density o Simple visual count small area, large organisms o Sampling methods count a small portion of total population and figure out the whole population. Markrecapture method (like the wrist bands to wear on campus by the ecology students) st Total population size = number of individuals in 1 catch X number of individuals in 2 catch / number of marked individuals in 2 catch Bias Dispersion patterns Clumped most common; resources in the environment tend to be clumped o Ex: water plants animals Uniform second most common; individuals are evenly dispersed. Occur when there is competition for resources. o Animals spread themselves out so there is less competition. o Ex: birds on a beach Random very rare. Resources are common and abundant Reproductive strategies Semelparity organisms reproduce once per lifetime o Ex: insects, salmon, some plants Iteroparity organisms reproduce more than once in its lifetime o Seasonal Iteroparity organisms reproduce every season, or every year. Distinct breeding season. Ex: Birds o Continuous Iteroparity organisms reproduce repeatedly, any time of the year Ex: chimps, humans Age classes Semelparous organisms sets up a cohort, a group of same aged young. o Ex: kids in kindergarten and schools grade level = students about the same age Iteroparous organisms young of different ages. Number of young in a population tells us what populations are growing and shrinking o Many young = high population o Few young = smaller population Do not want an imbalance of age classes Survivorship Curves Survivorship curve the plot of the number of surviving individuals at each age class 3 patterns o Type I Have a lot of young that tend to survive until old age; fewer offspring provide a lot of parental care Ex: humans o Type II Uniform take of decline Ex: Birds, reptiles o Type III Have a lot of young and little to no parental care Ex: fish (think Finding Nemo!) How populations grow 2 patterns: 1. Exponential growth abundant resources; Jshaped curve a. Rate of population growth (rapid) = (r) b. Reintroduce an organism to an area i. Elk/ conservation efforts c. Introduce an exotic species i. Rabbits in Australia. In 1859, two dozen rabbits 1875 millions of rabbits. d. Human population growth 2. Logistic growth resources are limiting; Sshaped curve a. Carrying capacity (K) – the upper limit of a population size b. Ex: bacterial culture Factors that regulate population sizes Density dependent factors = mortality factors that become more prominent as population size grows o Parasitism, predation, and competition o High population size = high parasitism, predation, and competition Density independent factor = factors that cause mortality but does not have anything to do with the size of the population o Physical factors: weather, drought, floods, etc. Life history strategies Rselected species (exponential) o High population growth, poor competitors o Ex: a weed Kselected species (logistic) o Slower population growth, good competitors o Population size tends to be at, or near, carrying capacity. Pretty much at equilibrium o Ex: an oak tree ** Table 56.2: Characteristics of r and KSelected Species** Human population growth Rate of growth o Overall 2006, 146 people born/ minute o Developed nations 2006, 2/min o Less developed nations 2006, 144/min Exponential pattern Earth’s Carrying capacity Lifestyle (resource use) Total fertility rate o 2.1 (offspring produce per couple) needed for zero population growth Ecological footprint Chapter 24: Population Genetics Definitions: Population genetics the study of genes and genotypes in a population. o Allele frequencies o Want to see if allele frequencies change over time Gene pool all genes (alleles) in a population. Population a group of members of a species in an area that can interbreed. o Some populations have large ranges and some are discrete Microevolution: Definition: Change in gene pool of population, over time. 1. Introduce new genetic variation: mutation, horizontal gene transfer, etc. 2. Evolutionary mechanisms: natural selection, genetic drift, etc. Selective survival of genotypes that confer reproductive success. Natural selection acts on characteristics that give a survival advantage. o Ex: reproductive success Modern description of natural selection: 1. Random mutations alter protein function. 2. (If above is a beneficial) enhance an individual’s survival or reproductive success. 3. More likely to survive and contribute their alleles to the gene pool 4. Significantly altering the characteristics of a population after many generations. a. Changed gene pool b. Changed characteristics of a population i. Better adapted ii. More fit Natural selection can only act on phenotype Genotype phenotype If phenotype is not changed = no natural selection Natural Selection Patterns Directional selection o Favors one extreme phenotype o Initiators Mutations gives a higher fitness value = it will be favored. That mutation should increase in population Environmental change Stabilizing selection o Favors intermediate phenotypes Act against the extreme phenotypes Ex: Bird clutch (the number of eggs laid by a bird in a nest). Birds with too many or too few eggs. What’s favored is the medium of eggs. Disruptive selection (Diversifying selection) o Favors two or more phenotypes o Most likely to occur in diverse environments Continuous nothing separating contaminated and uncontaminated. Isolated * Metalresistant: on contaminated site * Metalsensitive: uncontaminated site Members can’t interbreed Balancing selection o Maintains genetic diversity o Balanced polymorphism 2+ alleles are kept in balance in a population o 2 common ways 1. Heterozygote favored heterozygote advantage a. Ex: Sickle Cell b. Ex: Malaria Negative frequency dependent selection o Rare phenotypes are favored Ex: red and yellow flowers not producing nectar, but having pollen. Bees go back and forth, pollinating from one color flower to the next, making one color rare. o “Mental search image” predator/prey examples. Looking for a certain shape. Sexual selection o Certain traits o Choose a mate and successful mating o Male vs Female affects males more than females. (Males compete over female, females generally do not) o Secondary sexual characteristics Sexual dimorphism difference in appearance between males and females. Animals too= peacocks and parrots o Intrasexual selection: members of same sex. (Large horns in some sheep, large claws in some crabs) Male vs male Female vs female o Intersexual selection: members of opposite sex. Females choosing males. (Tend to choose males with “good genes” showy characteristics) Ex: peacocks. Females choose to mate with males with large, pretty tail feathers; healthy. Cryptic female choice: female is not consciously making a choice on who to mate with; physiological response. Prevent inbreeding Happens a lot with ducks, reptiles, wind pollinated plants o Why do males compete? Chances to have more offspring o Why are females choosy? To have a healthy offspring with good traits o Sexual reproduction can be directional, stabilizing, disruptive, or balancing Other factors: Change in allele frequencies in a population Random genetic drift o Based on random events unrelated to fitness. “Bad luck” Ex: Tornados, floods, etc. o Frequency reaches 0% or 100% 0% = allele has been eliminated from population. 100% = allele has been fixed in population. o Rate depends on population size Bottleneck o Population reduction and rebound o Random o Results in less genetic variation o Example: Cheetah about 1012 thousand years ago. Almost extinct, rebounded and most cheetahs has almost exact same genes. Makes them less fit. o More likely to go extinct after a bottleneck. Founder effect o New colony few individuals start a new colony in a new environment Less genetic variation o Example: Amish. In 1770 3 couples (6) came and started a new colony. Dwarfism allele and the 6 people, who came to this colony, increase in dwarfism7% Gene flow o Movement of alleles into and out of a population o Different from drift = enhance of genetic diversity o Prevents speciation new species Nonrandom matingindividuals are choosing a mate based on similarities/dissimilarities o Assortative mating mate with individuals with similar phenotype o Disassortative mating mate with individuals with dissimilar phenotypes o Inbreeding mate with related individuals Increase in recessive alleles homozygotes. The population as a whole will be less fit. Inbreeding depression a downward spiral of inbreeding and less fitness. Small population leads to more inbreeding decrease fitness (continues in a circle until ultimately leading to extinction.) Ex: Florida panther low sperm quality. Introduce panthers from Texas to breed and hopefully bring Florida panther out of the cycle. Chapter 25: Origin of Species and Macroevolution Speciation the process that leads to new species o Macroevolution new species, or new groups of species o Species o Time frame very similar, very dissimilar. Some differences = subspecies Indentifying characteristics: Morphological traits what an organism looks like; physical traits o Physical characteristics o Drawbacks Ability to interbreed o Reproductive isolation Prevents successful interbreeding Drawbacks some have ability to interbreed and others don’t; asexual and extinct species Used mostly for closely related, modern, sexually reproducing organisms Molecular featuresgenes and chromosomes o Compare genomes To identify similarities and differences among different populations. Gene sequence, chromosome characteristics, etc o Difficult What is the cut off? o Humans and Chimps are 96% similar Ecological factors o Based on ecological niche the role an organism plays in its community Habitat + life history o Mainly used in bacteria and viruses o Drawbacks Species Concepts a way to define what a species is Biological species concept interbreed and produce viable, fertile offspring (applies to more organisms) Evolutionary lineage concept species are defined by their evolutionary lineage Ecological species concept A group of organisms that have the same niche must be the same species Reproductive isolating mechanisms reduce or eliminate gene flow Prezygotic barriers prevent fertilization of egg/ prevent formation of zygote Pstzygotic barriers prevent viable, fertile offspring from forming (Figure 25.2 on page 511) Prezygotic barriers Habitat isolation no contact with each other at all Temporal isolation two groups of organisms don’t breed at the same time. Not active at the same time (day/night, spring/fall) Behavioral isolation prevents mating because other individuals aren’t doing the right thing. Ex: bird songs and dances Mechanical isolation Might try to reproduce, but reproductive organs are incompatible. Ex: poodle and mastiff Gametic isolation Try to reproduce, but the egg and sperm are incompatible Postzygotic barriers Less common Hybrid inviability the egg gets fertilized, but it can’t pass a certain stage Hybrid sterility successfully form an egg, you get offspring, but they are sterile = interspecies hybrid Ex: A donkey and a horse = mule Hybrid breakdown you get a viable, fertile offspring but eventually get less fit and are unable to reproduce Patterns of speciation Speciation formation of a new species Underlying cause accumulation of genetic differences Cladogenesis the division of 1 species into 2 species 1. Allopatric speciation the most common method; occurs when species become geographically isolated. (Prevent gene flow) 2. Sympatric speciation less common; organisms are in the same range, but there is no interbreeding Anogenesis the opposite of Cladogenesis Allopatric speciation Individuals of a species become geographically separated Natural selection causing different adaptations to the two groups making 2 species Ex: Portfish Adaptive radiation Occurs when you have a single species evolving into many species. (When a new niche opens to environment) Ex: Birds on an island adaptively range out to fill the niches Hybrid zones Sympatric speciation An organism diverges into two or more different species Same range No physical barriers to interbreeding Polyploidy plants Adaptation to local environments the species have two groups that slightly change behavior to adapt to environment Sexual selection Pace of speciation Gradualism each new species evolving slowly over a rate of time Punctuated equilibrium Both views have merit 10-16-12 Bio I Cell Cycle Chromosomesgenetic material/ DNA + proteins o Chromatin DNA + proteins (loosely coiled) Genes o Located on chromosomes Eukaryotic chromosomes o Linear form Chromosome sets o Chromosomes occur in sets o Humans23 sets, 46 total Sets 122 = somatic chromosomes Set 23 = sex chromosome (x, y) o Diploid, 2n cell/organism contains 2 full sets of chromosomes Somatic cells = body cells Homologues = chromosomes 1 (female), 1 (male) o Haploid, 1n – organisms with 1 set of chromosomes Gametes = egg and sperm Mitotic Cell Division o Mother cell divide in two o Daughter cells o Mitosis ( nuclear division; dividing nucleus) and cytokinesis ( cell division; divide cytoplasm and organelles) Mitosis and cytokinesis picture in book! o 24 hours life cycle for cell cell goes through phases o about 11 hours/longest phase *interphase (I phase) 3 smaller phases o [g= gap], [s=synthesis] g1normal activities, synthesizing s replicate DNA g2 producing proteins for cell division o Mitosis = m phase Prophase Prometaphase Metaphase Anaphase Telophase (separate from that = cytokinesis) Preparation for cell division o DNA replication o Sister Chromatids Centromere protein that holds 2 sister chromatids together Kinetochore Mitotic Spindle apparatus sort chromosomes during mitosis. o Mitosis o Mitotic spindle apparatus proteins o Centrosomes (2 centrosomes; one at each end of cell) o Spindle microtubules (originate from chromosomes?) Astralanchor spindle apparatus to cell Polar push off one another to elongate the cell (XX) Kinetochore attach to kinetochore proteins on the sister chromatids Interphase o DNA has replicated o Chromatin o Centrosomes Prophase (1 phase of mitosis) o Sister chromatids condensed (X) o Nuclear membranebreak down o Chromatids condensed chromosomes Ex: 6 chromosomes, 3 homologous pairs, 12 sister chromatids Prometaphase o Nuclear membrane = completely dissolved o Centrosomes = moved to the poles o Spindle fibers = attached (fully formed) o Kinetochore Kinetochore microtubules= attached to kinetochore proteins on sister chromatids Metaphase o Pairs of sister chromatids align Metaphase plate invisible line o *aligned in a single row along the metaphase plate.* Anaphase o Sister chromatids broken apart o Individual chromosomes Kinetochore microtubules shortening to poles Pole Polar microtubules pushing against one another; lengthening the cell. Telophase o Chromosomesreached the poles o Nuclear membranesreform Cytokinesis o Daughter cells (2 of them) Animals cleavage furrow Ex: jawstring going around cell until there are 2 fully formed cells. Ex: water balloon with string tightening two individual cells Plants cell plate Form new cell wall to separate mother cell into 2 daughter cells. Meiosis o Sexual reproduction 1n sperm + 1n egg = 2n zygote o Meiosis (need picture in book) Chapter 1: An Introduction to Biology Biology the study of life (Bio=life; logy=study of) Properties of Life o 78 properties o Important one: unity and diversity of life *Unity all living organisms share a common characteristics; common ancestor. *Diversity we are different from one another although we share common ancestors. (Evolution= developed differences.) Ex: grandparents and looking “justlike” them, but sharing common things personality. (Family tree) Seven Characteristics of Life 1. Cells and Organization cells serve to separate living organisms from environment. (Cell=smallest/simplest unit of life.) 2. Energy use and metabolism we all get energy from environment. We use energy to maintain cellular respiration. a. (Energy=organization) b. (Metabolism=photosynthesisbuilding of sugars; building/breaking of molecules.) 3. Response to Environmental Changes/ Adaptations a. Responding (body) to environmental changes i. Ex: hotsweat ii. Ex: coldshiver b. Adaptations longterm responses to change. 4. Regulation and Homeostasis we all regulate cells in the body. a. Homeostasis relatively stable internal conditions. b. Normal for humans: i. 98.6=temperature ii. 6080=heartbeat iii. 2 pH= stomach 5. Growth and Development a. Growththe increase number or size of cells. b. Developmentdevelopment (embriotic and fetal development) of growth. [Acquiring development] 6. Reproduction a. Cells and organisms must reproduce. 7. Biological Evolution a. All living organisms evolve. b. Populations (whole species) change over time. Levels of Organization o Atoms smallest units of elements. Combine to form molecules and macromolecules. o Macromolecules really big molecule combine to form cells. o Cells combine to form tissues. o Tissues the association of cells with different functions. They join and work with organs. (Only for multicellular organisms) o Organs composed of 2 or more tissue types. (Only for multicellular organisms) o Organism has all characteristics of life. o Population group of individuals that’s the same species. o Community made up of 2 or more populations. o Ecosystem all the species and the physical environment. o Biosphere every place on Earth where life exists. Classification o Taxonomy a formal classification of living organisms based on a common ancestry. o 3 domains (domain=biggest groups) 1. Bacteriacommon in different environments; Single celled Prokaryotes 2. Archaea rare, live in extreme environments; Single celled Prokaryotes. a. Prokaryote= cells that lack a membrane bound organelle. 3. Eucarya Single or multi celled; eukaryote a. Eukaryote= cells that have membrane bound organelles. i. 4 Kingdoms in Eucarya: 1. Protista 2. Plantea 3. Animalia 4. Fungi BiggestSmallest Groupings o Groups get more narrow going down o Ex: Panther Domain Eukarya Kingdom Animalia Phylum Chordata Class Mamalia Order Carnivora Family Felidae Genus Panthera Species Onca o Chordata= all animals with a backbone. o Felidae= all cats. Binomial Nominclature o “2 names” o Scientific name is not complete without having genus and species. Ex: Panthera onca o Name= italicized, writtenout, and underlined. o Genus name= capitalized, species name is lowercase. Hypothesis or Theory? o Hypothesis A proposed explanation for some natural phenomenon. Look around the world at living things and make a hypothesis. Must make an experimentally testable prediction. Form an experiment and see if it’s true. Write hypothesis as a fact; already know. o Ex: Maple leaves drop leaves in the fall because of shortened sunlight. o Theory A broad explanation for lots of different natural phenomenon; supported by large body of evidence. Hundreds of thousands of experiments made and not one disproves your theory. Theory= “hypothesis on steroids.” o Ex: Theory of natural selection, DNA (genetic material) o They have to make many correct predictions. If disproven, revised or rejected. o You can disprove it, but you can never prove it. (Always keeping an open mind that we could be wrong.) o Hypothesis Testing Scientific Method Steps: 1. Observation o Leaves changing on campus. o Ex: Because colder and sunlight is shorter. 2. Hypothesis o The shorter amount of daylight causes the leaves to fall. 3. Experimentation o Get maple trees, plant in green houses. o Control group the amount of lights are the same for 200 days. o Experiment group slowly shorten light throughout the 200 days. o Key= only test 1 variable at a time; different between control and experiment group. 4. The Data o Chart 5. The Conclusion o Accept or reject the hypothesis. o Ex: The hypothesis is accepted. Chapter 2: The Chemical Basis of Life 1: Atoms, Molecules, and Water Biology based on the principles of chemistry and physics. Chemistry and Physics o Chemistry based on physics o Physics based on math All living organisms are a collection of atoms and molecules Atoms smallest functional units of elements o Cannot be further broken down by normal chemical or physical means. o Each atom is a particular, chemical element. o Subatomic particles Atoms made up of 3 subatomic particles Protons positive charge; make up nucleus of an atom Neutrons no charge; make up nucleus of an atom Electrons negative charge; not in nucleus, but circle around it. (e) o Protons and Neutrons are similar in size and mass, but are 1,800 times bigger than an electron. Normal balanced atom= no net charge Electrons occupy orbitals o Orbitals where the electrons move around the nucleus. Orbitals o Two main orbitals S P o Each orbital can hold a maximum of 2 electrons o The more electrons an atom has, the more orbitals it will have. o Orbitals are contained in energy shells. Shells= energy shells Nitrogen example o Nitrogen= 7 electrons 1 shell= 1S 2 shell= 2S orbital; 2P orbital Outer: 2 shell is not full o Valence electrons [3 e in P orbital= will interact with other atom’s electrons.] o When atom doesn’t have a full shell= more likely to chemically interact with other atoms. Atomic Number o The number of protons in an atom. o No net charge (zero) Atomic Mass o The number of protons and neutrons in the nucleus. (Almost equal in mass) Electrons= ~1,800 times smaller An atom’s mass relative to the mass of Carbon. o Is it bigger/ smaller than Carbon? o Carbon= 6P, 6e; atomic mass= 12 o Hydrogen= atomic mass of 1; 1/12 the size or atomic mass of Carbon. o Magnesium= atomic mass of 24; 2 times the mass of Carbon. Isotopes o Natural, occur in nature. o Forms in an atom that differs in the number of neutrons. o Number of protons in the atom are the same. Ex: Carbon 12 contains 6 p + 6 n Ex: Carbon 14 contains 6 p + 8 n Radioisotopes o Isotopes that have an unstable nucleus; lose energy in one of two way: 1. Emit subatomic particles 2. Emit radiation Ions o An atom that has lost or gained an electron. (Charged particles) o Net elect
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