Bio Diversity Exam 2 Notes Populations of a single species become isolated from each other and over time those pops Speciation requires multiple steps 1 diverge become different relative to their gene pool allele frequencies associated w particular traits could occur through NS as environment may differ btw the pops loss of gene flow no interbreeding limits allele diversity in newly isolated populations Mutations will differ btw populations genetic drift diffs in allele diversity in pops become fixed genes become increased common significant in pops this point each pop is limited in its ability to respond to new selective pressures driven by allele diversity Speciation by drift humans of species each species has elaborate courtships matingritials female will only respond to the courtship rituals of male of its own species Other isolating mechs evolve maintaining diffs NO GENE FLOW likelihood of genetic divergence traits Speciation populations of a single species become diff through reproduction isolation mutation NS genetic drift 2 genetic divergence interbreeding expensive is dead end other isolating mechs prevent reduce interbreeding hybrid infertility in viability basically reproduction is very energy allowing maintenance of genetic diffs selection against mating particular if there are costs associated with reinforcement after initial divergence of pops mating w a member of the isolated population hybridization does occur some hybrid infertility inavailibitlity when pied collard mate egg produced decreased survival from egg juv Speciation by NS island trunk morph a small pop of anoles id released on a empty if you go back 5 10 years later started as a tree food habitat become selective pressures speciation likely takes a long time affected populations are geographically isolated from each Allopatric Speciation other barrier new something that decresed dispersal gene flow strongly by genetic drift NS spp Generally dealing w closely related spp new recently evolved from a common ancestor adaptation by diffs groups of organisms to diff parts of the environment speciated foraging e g specialized adaptation Example of Adaptive Radiation African chichilds African Rift lakes target points of adaptive radiation subset of ravine species however it can also happen rapidly adaptive radiation Adaptive Radiation rapid production of any new Each lake tends to have its own species flock exposed to changing selective pressures Sympatric speciation isolation isolation reverses plants Speciation takes a long time to occur Speciation can also occur rapidly result in speciation extinction loss of an entire species existing species much less common than allopatric organisms occur together with no geographical should see increased likelihood of mating limited limited genetic divergence however speciation can still occur example mutation occurs where snail coiling mechanical isolation change in terms of host geological isolation Gradualism change occurs gradually intermed forms are present Punctuated Equilibrium Short burst of evolutionary change which can mutation occurs feather color small change vastly more extinct species than currently also opens up new niches that allow population separation genetic divergence possibly speciation increased dust in atoms decreased sunlight decreased light plants may lead to food limitation Decreased sunlight decreased temp increased effect on reptiles amphilla fishes mammals birds extinction can be associated w catastrophe e g asteroids collide w earth 65 million years ago an asteroid hit chicxulub coming up w standardized naming system is Chapter 23 Systematics Phylogenetic critical evolutionary framework TODAY 1 5 million named species another 3 5 30 million unnamed species technique tool for reconstructing evolutionary histories relationships based on direct evid of common ancesting fossils shared characteristics gene sequences structural habitat adjectives for description method of classifying and naming orgs w in an Goals of Systematics organisms TAXONOMY organisms inventory of all living things develop universal system for naming determine evolutionary relationships among wrote a book System nature binomial nomenclature each species has its Genus Species Homo Sapiens all names were in Latin dead language good Taxonomy started with Carolus Linnaeus own 2 word name because no one is working with the language other that with science universal name does not vary worldwide came up with hierarchial nomenclature Domain Carl Woese highest now micro organisms prokaryotes D bacteria D Archaea Kingdom Phylum Class Order Family Genus species Phylogenetics describing evolutionary relationships but on idea that classific systems should be built on evolutionary relationships as opposed to Each tree is a hypothesis closely related species are more similar to each structural similarities and differences other based on presence of shared traits than to other organisms physiology and behaviors common ancestor whereby a particular trait is selected for environment likely following that trait coming from mutation butterflies similarities differences are hearitable no acquired characteristics are used what can be mapped used traits characteristics often morphology DNA sequences assumptions are only valid if these orgs share a winged organisms pterosaurus birds bees avoids problem of convergent evolution Domain Archaea Bacteria lack a membrane bound nucleus Prokaryotes Eukarya Eukaryotes posses a membrane bound nucleus NOT LIVING VIRUSES PRIONS Kingdoms Bacteria Archaea Protista Plantae Fungi Animalia ALL DOMAINS ARE SUSCEPTIBLE Chapter 27 Viruses all viruses genetic info material RNA DNA DNA or RNA genetic material corkscrew like fashion Bacterial virus host Bacteriophage the DNA viral DNA Envelope Virus envelope called antigens Lynic Lysogenic Cycle newly produced DIES genome cell does not die LIVES capsid outer protein covering that surrounds the hellical capsid capsid is oriented in a helical capsid protein now from an icosahedron icosahedral head helical tail capsid contaning spider legs whiskers attaching helical capsid surrounding RNA structure forms around capsid called an antigen enevelope is studded w small projections Lynic bacterial call ruptures releasing virions Lysogenic viral DNA integrates enter host Lynic 1 2 cell 3 processes synthesis process 4 5 6 virion attaches to host cell following penetration viral Dna is injected into viral RNA hijacks take over
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