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Bio 200 Final Exam Study Guide

by: Nicole

Bio 200 Final Exam Study Guide BIO 200LLB

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Condensed version of All lecture notes from the semester, highlighting topics previously stressed on exams, as well as new material. Good Luck!
Evolutionary Biology
Lindqvist, C
Study Guide
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This 38 page Study Guide was uploaded by Nicole on Wednesday December 9, 2015. The Study Guide belongs to BIO 200LLB at University at Buffalo taught by Lindqvist, C in Fall 2015. Since its upload, it has received 353 views. For similar materials see Evolutionary Biology in Biological Sciences at University at Buffalo.

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Date Created: 12/09/15
Evolutionary Biology Final Exam Review Evolution’s Key Time Points: Time Event 4.6 BYA Earth Forms 4.0 BYA Earth begins to cool ~3.8 BYA First Life forms 2.5 BYA Oxygen accumulates (photosynthesis) 1.7 BYA 1 Eukaryotes 1 BYA 1 Multicellular Organisms 450 MYA 1 Land Plants 420 MYA 1 Land Animals 250 MYA Permian Extinction 230 MYA 1 Dinosaurs 200 MYA 1 Mammals 65 MYA K-T Extinction 2 MYA First Humans Panspermia-theory that life first evolved elsewhere in the universe but was seeded to Earth What Earth looked like 3.8 BYA -Molten rock -All life must have been aquatic -No free Oxygen -Created reducing atmosphere -Electron adding- molecules form very readily -High Energy Environment -Little to no UV blocking 4 Steps to Life on Early Earth: 1.) Abiotic Synthesis of Organic Molecules -Miller-Urey Experiment attempted to recreate Earth’s early atmosphere in 1953 -In early 1990’s we discovered that earth’s early atmosphere was predominantly composed of CO and N2, neith2r of which were found in original experiment -Samplings of the more modern experimental “oceans” that form contain the building blocks of life (amino acids, nucleotides, sugars, lipids, ATP), and were formed in only one week 2.) Formation of Polymers -Polymers (protein, DNA) form when monomers (amino acids, nucleotides) get together and form a chain -Role of Clay -Positively charged, rich in iron and zinc, which attracted negatively charged monomers -Would indicate that first life formed near clay-rich shores 3.) Formation of Protobions -Aggregates of abiotically produced organic molecules surrounded by a membrane -Lipids -Hydrophobic tails and hydrophilic heads form together to create liposome (lipid bilayer) -Forms cavity that can hold chemicals-begins to look like a cell 4.) Origin of Heredity Material -First hereditary material was likely RNA -RNA can be formed abiotically more easily than DNA can -Can replicate itself (even more likely in presence of Zinc) -Contains hereditary information -Has catalytic properties-can act as an enzyme (unlike DNA) -Recent research suggests that RNA can be composed completely of sugars and hydrogenous bases, both components that would have been found on early Earth -Viroids-may have led to first life -Tiny particles of raw RNA, smaller than a virus -Enough genetic information to infect a plant and trick the plant’s genetic machinery into replicating a viroid -Because they cannot replicate on their own, viroids still cannot be considered life History of Evolutionary Theory People to Remember: -Anaximander -Greek Philosopher-Transmutation, common descent -Carolus Linnaeus -Binomial Classification -James Hutton -Gradualism-Geologic differences happened over long periods of time -Adam Smith -Competition -Jean-Baptiste Lamarck -Acquired Traits (giraffes) -Thomas Malthus -Population growth limited by resources -George Cuvier -“Catastrophism”, fossils (extinction occurs) -Charles Lyell -Uniformitarianism-“Present is the key to the past” -Charles Darwin -Species change through time, common descent -Alfred Russel Wallace -Wallace’s Line, natural selection Darwin: Modern Five Parts of Darwin’s Theory: 1.) Individuals vary 2.) Populations tend to overbreed relative to available resources, leading to a struggle fro survival 3.) Better variations have better survival 4.) Survivors will reproduce & non-survivors won’t (not always necessary criteria) 5.) Traits leading to better survival & reproduction must be heritable Do Individuals vary? Yes! Do populations tend to overbreed? Yes- Oak trees put out many more seeds that can possibly survive. Somewhere between 0.01-0.1% of seedlings are expected to survive -One oak tree will release over one thousand acorns in its lifetime Do better variations for a particular environment have higher survival rates? Rosemary and Peter Grant- worked on Daphne Major Island in Galapagos -Two of Darwin’s finches live on this island-large and medium ground finch -Variation in head & beak size in medium ground finches -Survival of these birds is based on seed availability -1977-Severe La Nina -Extreme drought, extreme population decline (from 1,400 finches to 200 finches in just one year) -Soft seeds quickly eaten, leaving only hard seeds remaining -Birds with longer and deeper beaks out-survived those with smaller beaks -1984- El Nino, very wet year -Abundance of small seeds (can fall out of large beaks) -Smaller beaked birds survived better than those with large beaks -Solidifies theory that better variations have better survival rates Do survivors have more offspring and pass on their selected traits to the next generation? -Grants plotted beak size of parents by the beak size of offspring & found very strong correlation -Evolution actually changed the average beak size across generations, causing more birds to have large beaks -Concludes that traits leading to better survival and reproduction must be heritable Is Earth Old enough? -Hutton & Lyell both believed so -Depth of canyons & thickness of rock strata both indicate very long & gradual natural process, oldest found rocks dated to 4.6 billion years old Do fossils show that species are mutable? -Cuvier showed that extinction occurred and that recent species were no longer extant -Darwin’s fossils -Megatherium-Giant sloths 1.1m tall & weighed up to 6,000 lbs -Toxodon- capybara like species 1.5m tall & weighted up to 1.5 tons -Glyptodon-Giant armadillos, 1.5m tall, weighed as much as average sedan -Fossils were closely related to animals alive at the time, but were different species Do younger rocks strata have more modern fossils than older rock strata? -Lyell’s data on mollusks proved this to be true Are there fossils of intermediate forms? -Archaeopteryx fossils-have traits of both birds and reptiles-provides solid evidence of transitional forms -Whales, Horses & Tiktaalik (intermediate between fish & amphibian) all good examples of intermediate forms Gregor Mendel (1822-1884) Mendel’s Five-Element Model: 1.) Parents transmit information about traits to their offspring 2.) Each individual receives two copies of each factor to encode each trait 3.) Not all factors are the same and different combinations lead to different traits 4.) Two factors do not blend 5.) Presence of a factor does not guarantee it will be expressed- it can be latent Genotype -Alleles found in individuals -AA differs from Aa even if both flowers are purple Phenotypes -AA=Aa -Physical characteristics of organisms, phenotype ratio 3:1 Mendel’s 1 Law of Heredity-Principle of Segregation -Two parental alleles segregate during gamete formation to be rejoined at random during fertilization Monohybrid Cross: -Parental Generation Ry * rY -3:1 ratio Dihybrid Crosses-Mendel’s 2 Law of Heredity-Law of Independent Assortment Parental Generation: RRYY * rryy -F1- RrYy - Dihybrid Crosses lead to 9:3:3:1 phenotype ratio -In Dihybrid cross, alleles of each gene assort independently Mendel was Unaware: Genes are Sometimes Linked -Certain alleles are almost always expressed together -Linked genes are on the same chromosomes and do not assort independently Polygenic Inheritance -Traits can be controlled by multiple factors -Epistasis-Lab coat color determined by 2 genes that interact- without knowing gene type, it is impossible to know dog color -Sickle cell anemia-Multiple effect of one gene-decreased ability to transport oxygen but decreases susceptibility to malaria Dominance is Not Always Complete -Incomplete dominance: Parental phenotypes blend in the heterozygote -Blending ends with the heterozygote -Co-dominance-heterozygotes show both parental phenotypes unblended Environmental Differences’ Effect on Factor Expression -Siamese cats- melanin in Siamese cats is due to temperature- near core, temperature is too high to allow expression of melanin-producing enzyme Chromosomes: Karyotype-Map of set of chromosomes Chromatids-When chromosomes condense & become visible but before they replicate Sister Chromatids-The two identical chromatid copies formed during replication Centromere-Part of the chromosome that links sister chromatids Chromosome-Pair of sister chromatids form the chromosome Homologous Pair-Same chromosome type from mom and dad Mitosis -Interphase -DNA is diffused and hard to see, phase where DNA is replicated -Prophase -Mitosis begins -Chromatin becomes more compact & becomes visible, now consisting of identical sister chromatids -Mitotic spindle forms-structure that will pull the cell apart -Prometaphase -Nuclear envelope breaks down -Kinetochore microtubules, which are connected to the poles, attach to the chromosomes -Metaphase -Chromosomes line up at mid-line of cell-Equatorial position -Chromosomes are condensed and highly quarreled -Anaphase -Sister chromatids are pulled apart to opposite ends of the cell Telophase -Last phase of mitosis where chromosomes are fully separated -Cell cleaves in half to form two identical daughter cells that contain the same number of chromosomes as parent cell Meiosis: -Following interphase, chromosomes begin to condense and a meiotic spindle forms -Homologous pairs join in center of cell, each chromosome will end up at opposite ends of the cell -Cell divides to form 2 daughter cells -Daughter cells are genetically distinct & have only half as many chromosomes as parent cell (when gametes join, there will be the right number of chromosomes) Ploidy=number of copies of chromosomes A cell with one copy is a Haploid (1N)-Gametes Cell with 2 copies is a Diploid (2N) More than two copies is a polyploidy (xN) Mitosis: 2Nà4Nà2N Meiosis: 2Nà4Nà2Nà1N Crossing Over -Occurs in the beginning of meiosis when homologous pairs join -Enzymes break & rejoin chromatids on homologous chromosomes-DNA from non- sister chromatids can be exchanged -Now chromosomes from dad may have DNA from mom’s chromosome on it -Chromosomes may have many or very few crossovers Recombination -Now genetic material from parents is mixed-leads to much higher variation among offspring Gene Linkage -Distance between genes on chromosomes has a lot to do with whether or not they will be linked -Genes close together on chromosome are tightly linked, while genes further apart are loosely linked as they can be easily separated during recombination DNA -Double helix-two strands of genetic material (Discovered thanks to Rosalind Franklin’s X-ray of DNA) -Backbone made up of repeating sugar and phosphate units -H-bonds hold nucleotides together-specifically pair certain nucleotides together Four nucleotides: -Adenine (A)-pairs with Thymine -Thymine (T) -Cytosine (C)-Pairs with Guanine -Guanine (G) Semiconservative DNA Replication- Produces molecules with both old and new DNA, but each molecule contains one complete old and one complete new strand -Due to complimentary pairing, information of strands is rarely lost -Helix unzips original strand, breaks bonds between nucleotides and enzymes work together to bring new nucleotides to parental chain & form daughter strands -DNA Polymerase matches existing nucleotides on parental chain with complimentary bases & form bonds between the new pairs Transcription -Process of copying DNA to RNA, occurs in the nucleus Translation-RNA to proteins, occurs outside the nucleus RNA -Always single stranded -Adenine pairs with Uracil rather than Thymine Protein -Made up of amino acids -Codons-3-letter units that encode amino acids -Some codons stop translation Allele Frequency-The number of times that an allele occurs in a population How do Allele Frequencies change? 1.) Gene flow a. Migration of alleles from one population to another 2.) Non-random mating a. Assortative mating-organisms of similar phenotypes tend to mate together more often than expected by random chance b. Increases homozygous organism ratio 3.) Genetic Drift a. Random changes in allele frequencies-has bigger effect in small populations b. Founder Effect-When a portion of a population becomes separated and interbreeds to form new allele frequencies c. Bottleneck Effect-When a natural disaster wipes out the majority of a population. The remaining survivors will reproduce to create new, less diverse allele frequencies (Finches on Daphna Major island) 4.) Mutation a. Ultimate source of genetic variation, though not a driving force in changes to allele frequencies b. Findings of Francis Crick & Sydney Brenner: i. -Codons are not spaced and read in threes ii. -Reading frame is critical c. Point Mutations: i. Frame-Shift Mutations-disastrous effects, causes entire chain of amino acids to be translated incorrectly ii. Silent Mutations-also called synonymous substitution-no change in amino acid sequence iii. Missense Mutations-also called non-synonymous substitution- occurs when one amino acid is replaced by another iv. Nonsense Mutations- Substitution of a base by a stop codon- early termination of translation almost always results in the loss of function for the protein d. Chromosomal Mutations: i. Deletion-when large chunk of chromosome is deleted, causes a significant loss of genes ii. Duplication-when a large region of the chromosome is copied iii. Inversion- when a section of the chromosome is reversed & placed back into the chromosome. So long as this does not happen in the middle of a gene, it usually has no effect iv. Translocation-when a piece of chromosome attaches to it’s non-homologous pair during crossing over Meiosis Nondisjunction -Occurs when chromosomes fail to separate during metaphase 1 Aneuploidy -Have gained or lost a chromosome -Very common in sex chromosomes (5% of conceptions) -Klinefelter’s syndrome: XXY -Turner’s Syndrome: XO -Monosomy- when a gamete has lost a chromosome-fatal -Trisomy-gamete with an extra chromosome (occasionally individuals can survive this)-Down Syndrome –extra chromosome Polyploidy -Entire genome is copied, can be caused by meiotic error where homologous chromosomes do not separate or can be result of hybridization between 2 different species -Rarely happens in animals & is often fatal if it does occur -Extremely common in plants, bananas have 3 sets of chromosomes rather than 2 5.) Natural Selection Factors required for Natural Selection to Operate: -Must be variation in the population -Variation must lead to differences among individuals in lifetime reproductive success -Variation must be transmitted to the next generation Common Selective Forces 1.) Predation 2.) Climatic factors 3.) Parasitism 4.) Mate Attraction 5.) Resource acquisition Stabilizing Selection-When just one variation of a trait works best for the species -Decreases range of traits found in a population so that all species are closer to a mean value Directional Selection-When the environment changes, mean for a trait moves higher or lower Disruptive Selection-Where extremes exist for each trait range, but there is a very low percent of population near the mean Balancing Selection -Heterozygote advantage -Sickle-cell anemia-heterozygote has advantage of malaria immunity that homozygotes do not -Negative Frequency dependent selection -Fitness of a species becomes higher as the frequency of its genotype increases. Rare individuals have a higher fitness than common individuals -Maintains polymorphisms among prey species-rare species is less likely to be recognized by predators Sexual Selection-Traits are selected purely because they attract better mates Reproductive Strategies: -Mate choice -Mating frequency -Mate guarding -Long-term mating behavior (monogamy vs. polygyny) -Parental care -Offspring spacing Females are Selective: -Females invest far more in reproduction -Energy-Human eggs are 195,000x larger than sperm and contain far more nutrients -Time-Gestation and child rearing leave females to deal with their choices for years While Females Choose, Males Compete -Competition through aggression or display-over access to females -Sexual dimorphism-males have special characteristics like horns and antlers for fighting, and elaborate display characteristics (peacock feathers) In Absent Fathers, Females look for the oldest, largest & healthiest males -All of these traits show good genes, clearly the male has been able to survive & support himself for a long time Handicap Principle- Males show off characteristics that are actually a handicap to their survival -If a male bird has to carry around a huge set of healthy tail feathers (a handicap to him), he must be especially fit Runaway Selection-Elaborate & exaggerated male ornamental features that no longer serve a practical purpose for survival -Natural selection will eventually stop runaway selection, as impractical traits will lead to lower fitness Speciation-When small evolutionary changes add up to a big evolutionary change Allopatric: Occurring in separate, non-overlapping geographical areas Sympatric-Occupying the same overlapping geographic areas Pre-zygotic Isolating Mechanisms: 1.) Geographic: species from different locations do not mate, as they do not interact 2.) Behavioral: during the selection of a possible mate, individuals from different species may discard each other, as they don’t have the same mating rituals. 3.) Temporal: individuals from different species may mate at different times of the year 4.) Mechanical: different species may have different sex organs, which are not compatible 5.) Gametic: Chemicals In this case gametes won’t recognize each other and fertilization won’t take place. Postzygotic Isolation 1.) Hybrid viability: sometimes the hybrid dies prematurely. 2.) Hybrid fertility: even if an offspring is produced from the mating of different species usually they are infertile as they generally have a random mixed number of chromosomes (so it’s not the same even between hybrids). 3.) Hybrid breakdown: if the hybrid results to be fertile, the hybrid population might breakdown over time (offspring may be less fertile) “Missing Link” Isolation -Intermediate populations that link 2 populations together go extinct, the gene flow between 2 populations is cut off Horizontal Gene Transfer-Movement of genetic material between distantly related organisms & across typical mating barriers -Endosymbiotic Theory -Eukaryotes arose from horizontal gene transfer through symbiosis between multiple microorganisms Life has Two Characteristics 1.) Organized 2.) Replicates Itself Viruses: -Do not fit definition of life, though they are incredibly close 1.) Highly organized; use same kind of genetic storage as cells 2.) Replicate (with help), and mutate like other cells -Protein coat (capsid) core, containing nucleotides -DNA or RNA, Circular or linear genetic material -No cytosol (plasma membrane) -Do not perform metabolic functions -Not cells (virions) -Can respond to selective pressures & evolve to have higher fitness Virus Replications: -Replication is parasitic: virus infects host cell & tricks cell into replicating it, often destroying the infected cell Prokaryotes vs. Eukaryotes: Prokaryotes Eukaryotes Unicellularity Typically unicellular Uni- or multicellular Internal Structure No membrane bounded Highly organelles compartmentalized, many organelles Chromosomes Single, circular DNA Double membrane bound nucleus with multiple linear chromosomes Cell Division Binary fission Mitosis & meiosis Gene Transfer Horizontal Transfer Recombination Flagella Simple, single fiber Very complex, 9 + 2 structure Cell Wall Ubiquitous (peptidoglycan In some organisms (no or psuedomurein) peptidoglycan) Size (can be misleading) Typically small Larger Horizontal Gene Transfer -Gene transfer between bacteria & archaea significantly complicates our understanding of evolution Cell Walls -Differ in Bacteria & Archaea -Gram-positive or Gram-negative (Stain used to see various parts of the cell) -Archaea all considered Gram-negative -Thickness of peptidoglycan layer Bacteria Classification before Genetic Analysis: 1.) Shape (rod, sphere, spiral) 2.) Metabolism a. Aerobes (need oxygen) or Anaerobes (poisoned by oxygen) b. Autotrophs (self feeders) or Heterotrophs (other feeders) c. Chemoautotrophs- Make energy by breaking the bonds in organic chemicals. Use Carbon dioxide to make sugars 3.) Gram-positive vs. Gram-negative a. Low-GC i. More AT than GC bases in DNA sequence ii. Very diverse group, not all have cell wall iii. Endospore-heat resistant structures that can survive harsh conditions that would otherwise harm the parent cell iv. Some may not be active for hundreds of years, can lead to highly noxious species b. High-GC i. More GC than AT ii. Provide us with most of our antibiotics-attack other bacteria iii. Responsible of the mechanisms of composting 4.) Cyanobacteria are Critical Autotrophs -Carry out complex photosynthesis -Plant chloroplasts are derived from Cyanobacteria 5.) Can live as single cells or live in massive colonies Archaea Crenarchaeota-Love hot, cold, or acidic environments & are the most common marine archaeans Euryarcheaota-Contains Methanogens (methane-producing), Halophiles (high- saline environments), & extreme thermophiles Origin of Eukaryotes & Protists: Origin of the Eukaryotes -Eukaryotes arise between 2.7 and 1.7 billion years ago -Have cells much larger than prokaryotes, thicker walls, and an internal membrane Several events preceded the origin of the eukaryotic cell -Flexible cell surface -Cytoskeleton -Nuclear envelope -Digestive vacuoles -Endosymbiosis Eukaryotic Traits 1.) Multicellular-Allows for flexibility 2.) Sexual reproduction-Leads to increased genetic diversity (recombination) 3.) Compartmentalization-Organelles that carry out different functions in cell a. Requires several stages Evolution to eukarya -Loss of the cell wall (endocytosis) -Origin of the nucleus and ER (both the result of membrane enfolding) -Endosymbiosis “Living together in close association”-an ancestral eukaryotic cell engulfed an aerobic energy producing bacteria, but did not digest it -Over time this arrangement be came permanent, led to mitochondria -Endosymbiotic events are examples of horizontal gene transfer Origin of Eukaryotes -Began with ancestral protists (some scientists refer to them as microbial eukaryotes) -Protists are only unified by the fact that they all have organelles- highly paraphyletic Variations in Protist Traits reveal lack of Unity in the Group 1.) Locomotion 2.) Cell Surfaces a. Some protists have extracellular material to shield them from negative aspects of the environment 3.) Nutrition a. Chemoautotrophy-only observed in protists, photosynthesis 4.) Reproduction a. Both sexual and asexual protists Protist Groups -Alveolates are a diverse group identified by the presence of alveoli -3 types, have all developed very interesting types of nutrition - Apicomplexans -parasites with apical complex -Dinoflagellates are photosynthetic & have 2 flagella (one short, one long) within 2 grooves on their surfaces -Can cause red tides, during which times they release toxins that kill birds & other mammals -Ciliate-move using cilia & are heterotrophic - Stramenopila - characterized by the fine hairs extending from their flagella -Brown Algae-multicellular, include giant kelp -Diatoms-Unicellular with unique double shell of silica -Use both sexual & asexual reproduction -Do not have flagella (except for male gametes) -Important energy producers -Oomycetes-not molds- use external digestion -Most are harmless decomposers, but some can be serious plant pathogens -Rhizarians-All unicellular & aquatic -Foraminiferans-fossilize easily -Tiny organisms in shells -Excavates-very diverse, includes organisms that do not even have mitochondria -Diplomonads & parabasalids-lack of mitochondria likely a derived trait -Euglenids-can be heterotrophs or photoautotrophs -Reproduce solely through binary fission -Plantae -Amoebozoans-contain amoebas & the slime molds -Loboseans- fit definition of “classic amoeba” -All heterotrophic -Plasmodial & cellular slime molds -Can exist asexually so long as there is enough food -Ooze over particles, engulfing food -Opisthokonts-Contain fungi & animals -Ancient choanoflagellates are ancestral to animals Land Plants Adaptations -Embryophytic- Need embryos to stay moist -Cuticle- Keep moisture in -Stomata-Small holes that open to let moisture in and close to keep plant from drying out -Pigmentation-Blocks UV radiation in absence of water -Fungal relationship-Develop mutual relationship with fungi that help plants absorb nutrients from soil -Tracheid cells-Allow for transfer of water & nutrients throughout plant & allow them to become larger -Thick spore walls-Protect plant from drying out -Seeds-Ultimate embryo protection Notable differences from Animals: -Diplontic life cycle-only diploid stage that’s multicellular or undergoes mitosis -Haplodiplontic life cycle: alteration of generations-gametophytic (multicellular haploid organism) alternates with sporophytic (multicellular diploid organism) Sporophyte -Meiotic event represents change from diploid to haploid Gametophyte-produces gametes through mitosis -When gametes fuse we call it syngamy, or fertilization -Represents transition from haploid to diploid generation -Everything below this point is 2N -Major difference between plant and animal lifecycles is the length of gestation and haplonic phase Primary vs. Secondary Endosymbiosis Primary-Eukaryotic Cell engulfs bacteria & codependence develops. A bacterium takes on functions of the cell -Chloroplasts result from Primary Endosymbiosis: a single event that gave rise to red & green algae (two membranes) Secondary-Eukaryotic cell that engulfed another eukaryotic cell, which had already engulfed bacteria -Brown algae is an example of a secondary endosymbiosis (engulfed red or green algae to get their chloroplasts; three membranes) Land plants all arise from green algae lineage & therefore are all photosynthetic Green Plants-Include both land plants & all green algae -Chlorophytes-Contain most species of green algae -Flattened cell form -Contain both unicellular organisms & complex, mobile organisms -Stoneworts-Thought to be most closely related to land plants -All show branching apical growth (growth only from the tip of the organism, common in all land plants) Non-Seeded Land Plants The transition to Land -Moss is most ancestral land plant -Land Plants are non-vascular, meaning that they have no tracheid cells Non-Vascular Plants (Bryophytes) 1.) Embryotic 2.) Gametophyte dominant 3.) Sporophyte dependent on gametophyte 4.) Require water for sexual reproduction -Includes mosses, liverworts, and hornworts System of Transport -Xylem-moves water & minerals upwards through the plant -Phloem-moves sugar & nutrients down (phloem=flow down) -Both provide structural support for the plant Seedless Vascular Plants (Tracheophytes) 1.) Embryophytic 2.) Sporophyte dominant 3.) Free-living gametophyte 4.) Can grow to be very large -Tracheophyte gametophytes are very small Club mosses -Simple leaf-like structures, vascular plants Monilophytes -Monophyletic group of vascular plants -Sister group to seed plants -First group to have more complex leaf veins (megaphils) -Includes Horsetails (readily dividing set of cells at each segment), and Ferns Seed Plants Benefits of Seeds -Embryophytic -Dispersal -Dormancy-delay between development of embryo and dispersal of the seed -Allows time for dispersal-gives opportunity to find best growth conditions Gymnosperms -Monophyletic group Important facts about Seed plants -All heterosporous -Allow for dispersal -Allow for dormancy -Dramatic reduction of gametophytic phase -Sporophyte is the dominant form Gymnosperm Lifecycle: Terminology -Microsporangium -Microspore-develop into pollen grain after mitosis -Pollen Grain-male gametophyte (haploid) -Microgametophyte The female gametophyte is enclosed in protective tissue and is dependent on the sporophyte for nutrition Fertilization -The seed is the mature ovule containing an embryo (product of fertilization) -End of dependence on water for reproduction Gymnosperms are divided into Four Groups 1.) Cycads a. Ancient lineage that was extensive during age of dinosaurs b. Slow growing c. Can reach heights of 15 meters d. Resemble palms, though genetically they are nowhere close e. Do not flower, but bear cones f. Motile sperm that will swim down pollen tube 2.) Ginkgos a. Dioecious-has separate male & female individuals b. Believed there are no wild ginkgos left c. Males have cones, females do not d. Motile sperm 3.) Gnetophytes a. Only gymnosperms that share a form of tracheid cell-vessel cells or elements b. Once believed to be closer related to angiosperms than gymnosperms c. Gnetum, Welwitschia & Ephedra-Three types of Gnetophytes 4.) Conifers a. Most common gymnosperms Angiosperms-Flowering plants -Most successful group of plants -Have both flowers and fruit Flower Structure -Sepals-covering of flower -Petals-Colorful to attract pollinators -Anthers-Site of microspore pollen production -Filaments-hold up anthers -Stamens-Comprised of anther & filament -Ovary-Eventually becomes fruit, houses ovules -Ovules-House megaspores (which produce eggs) -Style-Where pollen must travel through to reach cell -Stigma-Where pollen lands -Carpel-Comprised of stigma, style & ovary -Each microspore divides into a tube cell and a generative cell -The generative cell divides to form two sperm cells -Both sperm cells will fuse with parts of the female gametophyte -Sperm & egg=2N zygote -Sperm and polar nuclei=3N endosperm Angiosperms Differ from Gymnosperms -Double Fertilization -2N zygotes and 3N endosperm -Flowers & fruit -Reduced cell number in gametophytes -Speed of pollen tube growth -Triploid Endosperm Angiosperm’s success is due to Vessel cells, rapid maturation, pollinators, and fruits Touring the Angiosperms: Fossils of Archaefructus -Thought to be a close ancestor to first angiosperms, dates back to 125 million years -Has fruit, though no petals or sepals -Male and female reproductive parts Amborella Trichopoda -Thought to represent one of the most ancient living angiosperms -Represents sister group to all other living angiosperms, dioecious species Basal Nymphaeales: Water lilies -80 species comprised entirely of aquatic plants -No vessel cells-live in water & therefore have no need for vessel cells Austrobaileyales: -Comprised of woody plants (star anise- dried fruit from a tree in China) Mesangiosperms Chloranthaceae and Ceratophyllum Magnoliidae -Large group of plants that include many economically important species (cinnamon, avocado, black pepper) -Trimerous flowers- multiples of 3 Eudicots -Represent 75% of all angiosperms -Tomato, Venus fly trap, coffee, cocoa -Multiples of 5, broad leaves with branching veins Monocots -Grains & grasses-Corn, wheat, rice, palms, bananas, orchids, tulips, lilies, coconut, ginger, onions, garlic -Trimerous flowers Two Main Types of Pollination -Abiotic -Water Pollination-Pollen must be relatively impermeable by water, but still able to pollinate -Wind Pollination-Wind rarely carries pollen more than 100 meters -Biotic-Insects, beetles, bees, butterflies & moth pollinate flowers Fungus: -Branch off the clade with choanoflagellates & animals -More closely related to animals than plants Fungus Share 6 Traits 1.) Most fungi have a number of cell types 2.) Fungi have cell walls with Chitin 3.) Some fungi have dikaryon stages 4.) Fungi undergo nuclear mitosis 5.) Many fungi have both sexual and asexual reproduction 6.) Fungi are heterotrophs that absorb nutrients Fungal Cell Types -Unicellular (can be flagellated) or Multicellular -Mycelium (fungus like) composed of long cell-like structures called hyphae -Hyphae can be septate (when septa separates structures) or coenocytic (without septa) -Most hyphae can be considered single, long, multinucleate cells -Groups of hyphae form complex structures: Mycelium -Cell walls with chitin-what gives cell’s their structure Dikaryons (2 nuclei) -Form from the fusion of two haploid mating strains -Though both nuclei are haploid, dikaryon cells are protected from lethal mutations that would be masked in a true haploid organism -Cannot self-fertilize Nuclear Division -The nucleus replicates and forms two copies, but the cell remains a single unit -Nucleus divides without breaking the nuclear envelope Reproduction -Can reproduce sexually & asexually, spores develop into new haploid individuals -Asexual reproduction is often done by spores in multicellular fungi Digestion -Fungi use external digestion & completely dependent on water-all are heterotrophs -Can feed in 3 different ways -Mutualists-exchange nutrients in a mutualistic manner -Saprophytes-Eat dead matter -Parasites-Eat living organisms Fungal Groups 1.) Microsporidia-Obligate parasites of animals, especially common in insects, crustaceans and fish -Host cells are penetrated by a tube inserted by Microsporida -Lack true mitochondria, but has mitosome instead 2.) Chytrids- likely paraphyletic -Aquatic with unicellular life stages -Flagella present -May be killing amphibians-becomes pathogenic at lower temperatures 3.) Zygomycetes -Bread molds that grow asexually -Do not have any septa, Zygospores 4.) Glomeromycota -Mycorrhizal and coenocytic fungi-form mutual or beneficial relationships with most plants and cannot live without host plants -Monophyletic group -Do not form mycelia with hyphae 5.) Ascomycota -Septate & dikaryon forming -Bear spores in sacs (asci) Group Contains: -Cup fungi, Yeast, common molds (Penicillin), Truffles, morels, Cheese molds, Plant pathogens (chestnut blight & Dutch Elm) -Cordyceps-genus of parasitic ascomycetes that infects insects and other arthropods 6.) Basidiomycota -Septate & dikaryon forming -Basidiocarp- houses the basidia that produce spores (can produce up to 40 million spores in an hour) Plant Review: Heterosporous Spore Production -Megasporangiumàmegasporeàmegagametophyteàeggs -Microsporangiumàmicrosporeàmicrogametophyte (pollen)àsperm Homosporous spore production -Sporangiumà single spore typeà gametophyte (bisexual)à eggs & sperm Double fertilization in Angiosperms: -One sperm cell fertilizes with the egg cell à 2N zygote -The other sperm cell fuses with the central cell (2N)à 3N endosperm (triploid) Animals: What Makes an Animal? 1.) Multi-cellularity 2.) Heterotrophy 3.) Lack Cell Walls 4.) Motility 5.) Sexual Reproduction 6.) Characteristic embryonic development 7.) Specialized Tissues Symmetry -The first form of symmetry to evolve was radial -Radial symmetry leads to body designs where parts around are arranged around a central point -Generally circular or spherical -Bilateral Symmetry-Where right & left halves are mirror images -Bilaterians-have top (dorsal) and bottom (ventral) portions Embryonic Development -Sponges have undifferentiated tissues & no symmetry -Diploblastic animals have two layers & radial symmetry -Ectoderm & Endoderm -Most animals have 3 layers of embryonic tissue (triploblastic) & bilateral symmetry -Ectoderm-Outer body covering & nervous system -Mesoderm-Skeleton & muscle -Endoderm-Digestive organs & intestines Bilaterians are further divided -Protostome mouths develop before their anuses: “first mouth” -Deuterostome anuses develop before their mouths “second mouth” The body cavity (coelom) influence movement -Roundworms have fluid filled cavity-hydrostatic skeleton-gain rigidity due to fluid -Movement is more efficient than on Acoelomate (flatworm) Changes in the animal body plan 1.) Symmetry 2.) Embryonic tissue layers 3.) Specialization of tissues and cell types 4.) Coeloms 5.) Segmentation The Basal Animals -Choanflagellates are the ancestors to all animals -The most basal lineage of animals is the sponges -Free swimming, though adults are anchored to rocks -Sponges have highly specialized cells called choanocytes which collect food as they pass by -Can reproduce either asexually or sexually -The Cnidarians have radial symmetry and tissues -Includes marine predators -Two body forms: Polyps & Medusae -Polyps-cylindrical & usually attached to something -Medusae-free-swimming, umbrella shape with tentacles surrounding mouth -The Placozoans & Ctenophora (comb jellies) are small groups Protosomes -Lophotrochozoans Bryozoans and entoprocts are marine colonial animals -The Flatworms (Platyhelminthes) are acoelomates with a true head and one gut opening -Flat because they lack organs to transport oxygen through the body -Hermaphroditic but do not self-fertilize -Rotifers are tiny, pseudo-coelomates with complex organs -Ribbon worms-acoelomates characterized by their proboscis -Similar to flatworms, though have mouth & anus -Can grow up to 20 meters long Annelids-segmented worms -Segmentation allows for Specialization of different parts -Reproduction -Digestion -Excretion -Feeding -Respiration -Locomotion -Annelid segments are a stack of hollow rings that can expand and contract independently, allowing for much more control that a single unit -Sensory organs are in the anterior segments-likeness to brain Two Classes of Annelids: -Earthworms and leeches -Polychaetes-often have one or more pairs of eyes or tentacles Mollusks -Three body part plan: -Foot-Used to direct movement & capture prey -Visceral mass-holds the organs -Mantle-covers dorsal portion of all mollusks & typically secretes a shell -Mollusks have specialized mouthpart called the radula-used to scrape algae off rocks, some have modified this radula into drill to drill through shells -Cross-fertilization is common among mollusks Four Groups of Mollusks 1.) Polyplacophora: The Chitons (~1000 species) -Bodies with eight dorsal plates -Herbivores, typically live in shallow water 2.) Gastropoda: Snails & slugs (40,000 species) -Some creep & others free swim -Tentacles common (eyes and chemo- or mechanosensing) -Nudibranch (sea-slug)-very brightly colored to signify toxicity 3.) Bivalvia: Bivalves (30,000 species) -Ligament holds shells closed -Most filter feed & have incurrent and excurrent syphons -Sedentary adults, but free-swimming larvae 4.) Cephalopoda: Octopus, squid, and nautilus (~800 species) -Marine predators with arms and tentacles -Jet propulsion-forcibly eject water to produce movement -Color & texture changing for excellent camouflage -Highly intelligent-developed nervous system & eyes (better eyes than vertebrates because there are no blind spots) Ecdysozoans -Monophyletic group that grows by molting -Horsehair worms have no mouth & guts are thought to have no purpose-eat only as larvae -Nematodes (roundworms) are species rich -World Health Organization (WHO) suggests that 1/3 population is at risk for infection by nematodes, with 1/6 already infected -C. Elegans -model organism for lab research -Tardigrades: called Water Bears-less than half a mm in size -Live in sand-once they dry they remain dormant until rehydrated -Onychophorans: Velvet worms are terrestrial and closely related to arthropods Arthropods: Four Major Groups: 1.) Arachnids-spiders, ticks, scorpions -Mouthparts are chelicera -Four pairs of legs 2.) Myriapods-Centipedes & millipedes -Mouthparts are mandibles -Bodies consist of head, one pair of antennae and repeated segments 3.) Crustaceans- Lobsters, crabs, pill bugs, barnacles -Mouthparts are mandibles -Two pairs of antennae -Five pairs of appendages 4.) Hexapods (Insects)-Beetles, ants, butterflies -Grouped together based on body design -Mouthparts are mandibles -Bodies have three regions -One pair of antennae, three pair of legs Trilobites: had jointed appendages -Became extinct ~250 MYA -Body plans dominated by jointed appendages -Have exoskeletons-Grow their new skeleton under the old one Echinoderms & Hemichordates: Deuterostome: second mouth that develops into anus Echinoderms -Echinoderms are first Deuterostome -Pentaradial symmetry means there are 5 axes of symmetry-special type of radial symmetry -This Pentaradial symmetry makes Echinoderms are very diverse animals, as does their Deuterostome development & triploblastic tissue layering -Internal skeleton made of hard plates (acts similar to a cell) -Covered by a very thin layer of skin-neurosensory cells that allow the animal to experience the world around them -Pump water into specialized structures through tubes-water vasculature system -Water enters the body through a small hole or pore and flows into structure called ring canal -Characterized by their oral and aboral surfaces (as they lack a head) -Reproduce both sexually and asexually -There are 20 extinct classes of Echinoderms, but only 3 extant groups: -Crinoids -Sea lilies and feather stars -Sea lilies attach to rock-main body is a cup that contains water vascularate system -500-700 arms that radiate from the cup containing tubes -Echinozoans -Sea urchins, sand dollars, and sea cucumbers -No arms, hard to see pentaradial symmetry -Can be toxic -Asterozoans -Sea stars & brittle stars -Among the most important predators in most marine habitats Hemichordates: Acorn worms -3 Part Body Plan: Proboscis, collar, and trunk -Can be up to 2m long & live in sandy or muddy marine environments Chordates: Our phylate -Three Chordate Groups: Lancelets, tunicates, and vertebrates (most are vertebrates) What Makes a Chordate? -Hollow nerve cord-Differentiates during development into brain and nerve cord -Notochord -Pharyngeal slits/pouches-Connect pharynx to external environment -Postanal tail-At some stage in development all chordates had a tail -All chordates are segmented Lancelets vs. Tunicates -Only non-vertebral chordates -Fairly small groups -Most chordate traits are absent in adult tunicates -Lancelets clearly show chordate traits Invasion of Land What Makes a Vertebrate? 1.) Heads 2.) Endoskeletons supported by vertebrae 3.) Internal organs suspended in a coelom 4.) Circulatory system with a muscular heart Deuterostome Tree -Tunicates may not be our sister Taxa; we may be closer to the hagfish Vertebrate Groups 1.) Fish a. Not a monophyletic group b. Five Unifying Traits i. Jaws & teeth ii. Paired appendages iii. Internal gills iv. Single loop blood circulation v. Nutritional deficiencies (unable to synthesize certain amino acids) c. Jawed fishes: Anterior gill arches became jaws and greatly improved feeding efficiency d. Sharks have lightweight, strong skeleton & up to 20 rows of teeth e. Bony fish have heavy, strong skeleton i. Swim bladder provides buoyancy-fish can increase or decrease the amount of air in the bladder 2.) Amphibians a. Land animals evolved from Lobe-fin fish- have muscular lobe surrounding a core of bones which form joints b. Challenges of Land invasion: i. Moving heavy bodies ii. Replacing gills iii. Increasing oxygen intake and delivery to larger muscles required for walking iv. Preventing drying out of eggs v. Preventing body from drying out c. Amphibia means “double life”-they spent time in both environments to ensure bodies did not dry out d. Ichthyostega was one of the first amphibians-strongly built with ribcage & developed lungs e. Amphibian Traits i. Legs ii. Lungs iii. Cutaneous respiration iv. Pulmonary veins v. Partially divided hearts f. Three modern amphibians: i. Frogs & toads-amphibians without tails, dependent on water fro reproduction ii. Salamanders-Long bodies & tails iii. Caecilians-burrowing worm-like group with jaws & teeth 3.) Reptiles a. Four Defining Reptile Traits i. Amniotic Eggs-internal fertilization ii. Dry Skin iii. Thoracic breathing-Makes reptile lungs more efficient than amphibian lungs iv. Improved Kidneys b. Reptiles are ectotherms-they can control their temperatures by moving in and out of the sun, rather than an internal heating system c. First Reptiles were Synapsids i. Pelycosaurs-dominant early synapsid ii. Therapsids evolved from early synapsid groups d. Diapsids contain crocodilians, dinosaurs, and birds-Also called archosaurs i. Skulls that allow the jaw to open much wider ii. Dinosaurs improved on early archosaurs body plan, giving them highly increased speed e. Four Extant Groups of Reptiles i. Lepidosaurs, includes Tuataras-very rare ii. Squamates-Includes Lizards & snakes iii. Turtles & tortoises-have sharp beaks in place of teeth iv. Crocodilians are large predators, have nests & parental care 4.) Birds-Evolved from the Dinosaurs a. Distinguished from other reptiles by four traits i. Feathers ii. Flight skeletons 1. Large breast muscles stretch from wing to prominent breast bone to power flight iii. Lung design 1. Consumes radically more oxygen than ground animals, need efficient oxygen intake 2. Fully separated pulmonary systemic circuits, 4- chambered hearts 3. Lungs always receive blood with highest oxygen content iv. Endothermy 1. Between 40-42º C body temperatures-higher than most reptiles b. Beaks & feet tell us a lot of bird habitats i. Filtering vs. probing beaks, swimming vs. perching feet c. Large flightless birds are likely the earliest birds (Ostrich) d. Passeriformes-Most successful group of birds 5.) Mammals -Smallest class of invertebrates -Mammals likely survived the extinction of the dinosaurs due to endothermy Unified by Five Traits: 1.) Hair 2.) Mammary glands a. Milk is calorie and fat rich, allowing for the development of the baby’s brain 3.) Endothermy a. 4-Chambered heart b. Higher metabolic rates c. Homoplasious in mammals and birds (has evolved separately) 4.) Sweat glands a. Cool mammals via evaporation 5.) Placentas a. Most mammals have internal gestation b. Placenta allows developing baby’s blood to come into close enough contact to mother’s blood to absorb nutrients, but bypass waste Two Groups of Mammals 1.) Prototherians (Monotremes)- movie 2.) Therians (Marsupials and Eutherians) a. Marsupials often have pouches b. Though they have amniotic eggs, no shell develops c. Most species of mammals are eutherians (Includes humans) i. Much more developed babies than Marsupials ii. Huge size range iii. Diverged quickly after the mass extinction of dinosaurs iv. Diverged as the continents broke apart during the late Mesozoic Primates Defined by Two Traits: -Grasping fingers & toes -Binocular vision (gives us depth perception), important for hunting Two Main Groups of Primates we usually recognize 1.) Prosimian-before the apes a. Paraphyletic group b. Strepsirrhini (Wet-nosed) 2.) Anthropoids-includes apes a. Haplorrhini (dry-nosed) Hominidae (Hominids): -Comprised of the great apes and humans -Humans and their direct ancestors are hominins Hominids vs. Hominins Traditional Classification Family: Pongidae (great apes) Family: Hominidae (modern humans and our close extinct relatives) New Classification Family: Hominidae (Great apes AND humans) Subfamily: Homininae (gorillas, chimpanzees, and humans) Tribe: Hominini (humans & our close extinct relatives) Strepsirrhini (wet-nosed)- most ancient primates -Includes Lemurs, bush baby, Loris -Some lemurs do not act like other Strepsirrhini; some are diurnal (awake during the day), very social and live in matriarchal societies Haplorrhini (dry-nosed) primates -Have developed color vision to adapt to daytime living -Extended parental care allows for longer learning time & more brain development Platyrrhines (New World Monkeys) -Live in South & central America Catarrhines gave Rise to two groups: 1.) Old World monkeys a. Tailless, include Rhesus macaque and Olive baboons 2.) Apes (hominids) a. Gibbons b. Hominids (great apes and humans) c. Asian apes & orangutans diverged first, though neither group is especially closely related to humans d. African apes and humans evolved most recently Where did we come from? 1.) Bipedalism is the only trait that distinguishes humans from other apes a. Allow for us to grasp other things not used for support b. Ardipitithecus may have been mostly arboreal i. Bipedal, allowing her to walk upright (though not for very long periods) c. Australopithecines is the first hominin group we have many fossils from i. Earliest Australopithecines were gracile 1. They could walk upright, but had much smaller brains 2. Lucy was an Australopithecus, her feet & leg bones were almost identical in function to those in humans ii. Second group of Australopithecines was most robust: Paranthropus d. All members of the genus Homo are called humans i. Australopithecus sebida may be the lineage Homo evolved from ii. First Homo species we recognize is Homo habilis 1. Much larger brain chamber than ancestors, but still only ~50% the size of modern humans 2. Short with long arms iii. Homo erectus 1. Longest lived human species 2. Nearly the height of an average modern male with 75% brain size of modern humans 3. Hunter-gatherers, first species to master fire, and first to leave Africa iv. Modern humans originated around 600,000 years ago 1. Short & stocky, moved to Europe & developed complex rituals 2. Homo sapiens come to dominate around 34,000 years ago 2.) Where did Homo neanderthalensis go? a. Assimilation Hypothesis i. Excessive hybridization led to single population b. Out of Africa theory (Currently supported) i. Separate lineages evolved & competition determined current population ii. Genomic data from archaic hominins suggest that our development may be more complex than this theory: Neanderthals and Denisovans Abiotic vs. Biotic Factors & how they Effect the Environment Abiotic: Climate is controlled by 3 factors: 1.) Variation in light intensity a. Light hits the equator more directly than either of the poles b. Hadley circulation- hot, dry air rises while cold, wet air sinks 2.) The angle of the Earth a. Because the Earth is on a 23.5º tilt, certain parts of the Earth receive more or less intense sunlight at different times throughout the year 3.) Variation in local conditions a. Topography-variation in elevation or slope b. Oceans & lakes more prevalent in Southern Hemisphere, more deserts north of equator c. Slopes can have microclimates that affect organisms living on them i. If a slope has soil that drains well, the plants on the top of the slope will need to develop to live in dry conditions ii. Water will pool at the bottom of the slope, causing plants to grow in a wetter environment d. Increasing elevation leads to adiabatic cooling e. Lake Erie has dramatic effects on our local climate- causes lake effect snow, but keeps us cooler during the summer 4.) Variation a. El Nino and La Nina events b. The Pacific Decadal Oscillation (PDO) i. Shift in surface temperatures of northern Pacific that last 20-30 years, fluctuating between warm & cold temperatures Biomes are defied by temperature and rainfall Tundra -Coldest & one of the driest climates, with high elevations & high altitudes -Soil is frozen-in the spring a few inches will defrost and allow for shallow plant growth Taiga -Boreal & temperate evergreen forest Temperate Deciduous -More species & rainfall than boreal forest Temperate Grasslands -Dry biome with same average rainfall as boreal forest Hot Desert -While some areas get almost no rain, there is diverse flora, cacti & other succulents Cold Deserts -More than twice the rain as hot deserts, still relatively dry climate though frozen Tropical Savanna -Also known as Tropical Grasslands, not enough rain falls to support a forest Tropical Rainforest -Highest production mass of any biome -Most of nutrients are tied up in massive trees-soils are therefore nutrient poor -Epiphytes-plants that grow on other plants, gain nutrients from air & water Species Ranges do not Equal Biome Ranges -Many species cross biome boundaries -Niche: the entire set of resources a species needs to survive Variation in niche might explain coexistence -Competition could lead to extinction of one competitor -May be partitioned to allow coexistence Two Ways to look at a Niche 1.) Fundamental: The entire area a species could inhabit 2.) Realized: The area a species actually inhabits a. A combination of biotic, abiotic & historical factors Robert MacCarthur -Studied Warblers, wanted to know how 5 different types of warblers ate from the same tree -Found that they used different locations on the tree to look for food -Clearly showed niche partitioning Competition-When two or more species need the same resource (-/-) Predation-When one species eats another (+/-) Symbiosis: -Permanent interactions of two species -Includes Parasitism, Mutualism, Commensalism, Ammensalism Selective Pressures: -When the climate or other species require a species to adapt, leads to changes in morphology and behavior Two Types of Competition: 1.) Exploitation-One species lowers the resources of another 2.) Interference-One species prevents the other from gaining access to a resource Intraspecific Competition is competition between members of the same species, while Interspecific is competition between members of different species Resources -Competition is more important where resources are limited -A resource is anything that an individual needs to support population survival and growth -Anything that is consumed or used up, therefore lowering it’s availability -Things that can affect survival and growth, but cannot be consumed, are Not resources (example: temperature-affects organism, but cannot be competed for) Coexistence: Resource Partitioning -Gasterostereus aculeatus fish species -Limnetic species-living in well-lit open surface waters -Benthic-the lowest level of water, including the sediment surface -Temporal partitioning- feeding periods of tadpoles are separated by 4-6 weeks each year -Character displacement-genetic difference (difference in size, beak shape) that reduces competition When intraspecific competition is high enough, it can lower interspecific competition Disturbance-Natural events that lower populations -Balances competition scale as recovery from the disturbance occurs Predation -Far more than a simple transfer of energy -Consumer resource interactions -Include classic predator/prey interactions as well as parasites and herbivory -Detrivores-eat things that are already dead, do not influence abundance or distribution of what they eat Prey Elimination -Invasive species can take over an area, killing all prey -Klamath weed Predators -Can limit prey ranges -Megapode birds do not live anywhere where Asian predatory mammals live because those predatory mammals typically eat eggs & it would be difficult to defend their eggs Predator/Prey Cycling -When prey population declines, the predator population follows it -Data on Lynx & Hair shows very specific cycles of 10-year increments Mechanisms of Coexistence 1.) Refuges 2.) Cycling 3.) Few Predators 4.) Generalist predators Many predators & prey species are coevolving Prey Defense Strategies 1.) Crypsis a. Hiding, most widely known way to avoid predators b. Cryptic coloration & object mimicry 2.) Chemical Defense a. Bombardier beetle-sprays noxious liquid that has the temperature of boiling water at a potential predator 3.) Toxicity a. Nudibranches consume jellyfish and transfer the toxicity from the jellyfish to their own bodies to protect against predators b. Often associated with warning coloration-aposematic coloring 4.) Armor a. Difficult for predator to access prey 5.) Behavioral defense a. Alarm calling, Distraction displays, Running, Herds 6.) Predator satiation a. Some species time reproduction so all young are born within a short period of time Sessile Individuals -Toxicity & armor used-Many plants have toxic chemicals in them or produce spines/bark that protect the main portion of plant How do Predators find Prey? 1.) Search images-Can smell prey or see in the infrared 2.) Avoid/use toxins-Ambush hunting, stalking, & pursuit 3.) Get


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