BIO 112 SI Sessions Sun 3 4 Tues 6 7 Thurs 6 7 HECC 201 BIOLOGY CHAPTER 18 EVOLUTION Evolution entire fundamental idea in bio change in populations throughout the earths history change over time o Evolutionary change takes millions hundreds of millions of years o descent with modification DARWIN WALLACE theory of evolution below is before these two Early thoughts of evolution o Aristotle born one way no change great chain of being Scala naturae ladder of species lowest plants to highest humans o Linnaeus 1707 1778 Orderly nested classification king phylip cried out for goodness sake Domain kingdom p Father of taxonomy all species has a binomial name o James Hutton 1726 1797 Slow continuous process for species to change geological features they change based on environmental conditions gradual o Charles Lyell 1797 1875 Father of geology Uniformitarianism same geologic processes in past as today o Lamarck 1744 1829 Linked evolution to adaptation inheritance of acquired traits Extinct species have been replaced by descendants with new features o The adaptations helped them survive in environment o Darwin agreed to these ideas First to propose a mechanism for evolution use disuse use it or lose it Inheritance of acquired characteristics Ex a dad giraffe stretched its neck longer to eat then passed it on o Evolution Misconception we don t evolve o Darwin Theory Natural selection 1 overtime things change decent with modification change by natural selection 2 Natural selection Part 1 all life is related thru decent w modification from a ancestor in the past evolution Part 2 Natural selection is the mechanism for evolution Heritable variation exist in most species Homology traits related by common ancestry human cat whale bat the mammal forelimbs are homologous Vestigial structures remnants of ancestral homologous structures w no present adaptive function our appendix Ex blind cave salamanders have eyes but are blind and our appendix has no function but we have it Convergence similar adaptations under environmental conditions Ex think stems and thorns in deserts cactus in America vs cactus in Africa Ex tree gliding mammals similar traits Scientific theory a broad a well supported hypothesis or explanation with rich predictive value Theory hypothesis that has not been rejected most well supported Theory of evolution by natural selection o Explains both diversity and unity of life o Accounts for from and function o Can predict outcome of environmental change Systematics the study and classification of biologicsal diversity o Taxonomy science of biological classification how organisms are assigned to taxa goal utility 8Nomenclature the process by which taxa are named goal stability o Rules to taxa taxonomy Texa are arranged in hierarchical ranks Names are treated as if latin regardless of origin EX harveya names for irish botanist William hennery Harvey founder Species names are binomials 2 names EX homo spahians Ex solamun noun meaning nightshade tuberosum adjective maning bearing a tuber L author citation Medieval herbals doctrine of signatures o If a plant looked like an organ we have then it was used to treat that organ Species an entity o A group of organisms that can be categorized into a biologically meaningful unit o Based on reproductive barriers if 2 members can reproduce offspring that can make their own then it s a species Speciation a process o The process by which new species arise Gradualism a slow gradual accumulation of heritable changes Branching one poputiion diverts into another population of species Reproductive isolating mechanisms RIMS o Prezygotic ways that stop reproduction and mating Caused by ecological or habitat isolation Temporal isolation Behavioral isolation Mechanical isolation if parts don t match up genitals then it wont mate Gametic incompatibility the sperm wont penetrate the egg o Postzygotic After the zygote is formed after mating Hybrid in viability Hybrid sterility doesn t have binomial names liger Hybrid breakdown o Issues with biological species concept hybrids They are not their own species o Trouble with the biological species concept extent organisms o Trouble with bsc asexual organisms Asexual organisms don t mate at all Morphological species concept species are groups of organisms with recognizable and heritable phenotype differences o Look like a species but are not o Trouble with this Two species may be indistinguishable but intersterility due to chromosomal differences Sibling species Species may look similar due to convergent evolution Similar due to common decent homology Taxonomist specific and arguably subjective Recap evolution decent with modification or change over time o The change in allele frequency over time CHAPTER 19 THE EVOLUTION OF POPULATIONS The Gene theory genes are passed doen from parent to offspring o Mutations or crossing over segregation during MEIOSIS can alter genes o An individual can pass on a trait that they don t express recessive trait Gregor Mendel austrian munk o Studies seven characteristics of garden pea plants o Set the entire basic model of genetics o Discovered laws that govern the passage of trais form on generation to the next found ratios Mendels Experiments manually cross pollinated plants for 8 years o One trait he looked for was flower color phenotypic o Mendels work led to the discovery that some traits are caused by different versions of the same gene allele Terms Homologous Allele gene Locus genes traits alleles can be found at a specific location on chromosome Genotype you need 2 alleles same or different One allele is dominant expressed in the Phenotype physical appearance Recessive alleles nonfunctional copy to create Blue or green eyes Mutations o Change in DNA spontaneous o Most are null however some are good and some bad o Accounts for variation and natural selection o Influences rate of evolution the faster the mutation the faster the evolution Population group of interbreeding individuals in the same area at the same time and isolated from other groups o Populations evolve not individual organisms o natural selection is for individual organisms Hardy Weinberg equilibrium and evolution of pollutions o Study of genetic pricipals and how they apply to poplutions P2 2pq q2 1 MEMORIZE THIS 2pq you have both alleles o P dominant allele ex A o Q Recessive allele ex a Allelic frequencies of p q 1 o Genotype frequencies o Pp p2 hmzyg dom P o Qq q2 GET NOTES FROM SLIDE o N pollution o 2n total
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