Ch 22 Descent with Modification Fossils- Relics or impressions of organisms from the past, usually found in sedimentary rock. Fossils- Relics or impressions of organisms from the past, usually found in sedimentary rock. Paleontology- the study of fossils Paleontology- the study of fossils Cuvier- Catastrophism- each boundary in strata corresponded to a catastrophe that destroyed the species living there at that time. Cuvier- Catastrophism- each boundary in strata corresponded to a catastrophe that destroyed the species living there at that time. Hutton- gradualism-profound change is the cumulative product of slow but continuous processes. Hutton- gradualism-profound change is the cumulative product of slow but continuous processes. Lyell- Uniformitarianism- earth processes have not changed throughout history. Lyell- Uniformitarianism- earth processes have not changed throughout history.

Fossils fish oldest footprints fish oldest footprints fish oldest footprints

Descent with modification Darwin was influenced by both Hutton and Lyell. Darwin was influenced by both Hutton and Lyell. Earth must be very old, not 6000 years as theologians suggest. Earth must be very old, not 6000 years as theologians suggest. Lamarck- Use and disuse- but was in inherited. Lamarck- Use and disuse- but was in inherited.

Darwin Charles Darwin Charles Darwin HMS Beagle 1831 HMS Beagle 1831

Darwin Did not use the word evolution, but instead “Descent with modification” Did not use the word evolution, but instead “Descent with modification” Natural selection: Natural selection: All species produces more offspring than can possibly exist. All species produces more offspring than can possibly exist. Only a fraction will survive to reproduce. Only a fraction will survive to reproduce. Resources and environment dictate the survival rate. Resources and environment dictate the survival rate. All individuals of a population vary extensively. All individuals of a population vary extensively. Individuals best suited to environment will survive and reproduce. Individuals best suited to environment will survive and reproduce. Natural selection is the result of change over enormous tracts of time. Natural selection is the result of change over enormous tracts of time. Stanford evolution rap Stanford evolution rap Stanford evolution rap Stanford evolution rap

Evidence of Evolution Biogeography- geographical distribution of a species. Biogeography- geographical distribution of a species. Fossil record-Transitional fossils linking past and present Fossil record-Transitional fossils linking past and present Comparative Anatomy- Homologous structures Comparative Anatomy- Homologous structures Vestigial organs-No longer has a function. Vestigial organs-No longer has a function. Comparative Embryology Comparative Embryology Ontogeny- development of an individual organism Ontogeny- development of an individual organism Phylogeny- evolution of the species Phylogeny- evolution of the species Molecular Biology- common genetic code Molecular Biology- common genetic code claymation evolution claymation evolution claymation evolution claymation evolution

Phylogeny Comparative Anatomy and Embryology Comparative Anatomy and Embryology

Ch 23- The Evolution of Populations Population-group of individuals of the same species. Population-group of individuals of the same species. Gene Pool- total aggregate of genes in a population Gene Pool- total aggregate of genes in a population Hardy-Weinberg theorem-shuffling of alleles by meiosis and random fertilization has no effect on overall genetic structure of a population. Gene pool in equilibrium(non- evolving) Hardy-Weinberg theorem-shuffling of alleles by meiosis and random fertilization has no effect on overall genetic structure of a population. Gene pool in equilibrium(non- evolving) Must have: Must have: Very large populations Very large populations Isolation from other populations Isolation from other populations No net mutations No net mutations Random mating Random mating No natural selection No natural selection Hardy-Weinberg equation examples Hardy-Weinberg equation examplesexamples

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Ch 23- cont. Microevolution –generation to generation change in frequency of alleles. Microevolution –generation to generation change in frequency of alleles. Causes: Causes: Genetic Drift-changes in gene pool due to chance Genetic Drift-changes in gene pool due to chance Gene Flow-genetic exchange between populations Gene Flow-genetic exchange between populations Mutations-change in organism’ DNA Mutations-change in organism’ DNA Natural Selection- accumulates and maintains favorable genotypes in a population. Natural Selection- accumulates and maintains favorable genotypes in a population.

Natural Selection Stabilizing - Directional - Diversifying Stabilizing - Directional - Diversifying

Ch 24- Origin of Species Species- interbreed with each other and have fertile offspring. Cannot produce fertile offspring with other species. Species- interbreed with each other and have fertile offspring. Cannot produce fertile offspring with other species. Prezygotic barriers- impede fertilization of egg if different species attempt to breed. Prezygotic barriers- impede fertilization of egg if different species attempt to breed. Postzygotic barriers- prevent the hybrid zygote from developing into a viable fertile adult. Postzygotic barriers- prevent the hybrid zygote from developing into a viable fertile adult. ligers and tigons ligers and tigons ligers and tigons ligers and tigons

Speciation Allopatric speciation- a geographical barrier physically isolates populations and blocks gene flow. Allopatric speciation- a geographical barrier physically isolates populations and blocks gene flow. Sympatric speciation- intrinsic factors, such as chromosomal change (in plants) and nonrandom mating (in animals) alter gene flow. Populations become genetically isolated even though their ranges overlap. Sympatric speciation- intrinsic factors, such as chromosomal change (in plants) and nonrandom mating (in animals) alter gene flow. Populations become genetically isolated even though their ranges overlap. Adaptive radiation- evolution of diversely adapted species from a common ancestor. Adaptive radiation- evolution of diversely adapted species from a common ancestor.

Origin of Species Adaptive radiation- evolution of diversely adapted species from a common ancestor. Ex Adaptive radiation on Island Chains.

Speciation Gradualism- gradually diverge more and more in morphology due to adaptations. Gradualism- gradually diverge more and more in morphology due to adaptations. Punctuated equilibrium- new species change most as it buds from parents and then changes little. Punctuated equilibrium- new species change most as it buds from parents and then changes little.

Ch 25- Tracing Phylogeny Fossil record- Order of fossils in sedimentary rocks. Relative dating. Fossil record- Order of fossils in sedimentary rocks. Relative dating. Absolute Dating or Radiometric dating of fossils Absolute Dating or Radiometric dating of fossils

Tracing Phylogeny Phylogeny has a biogeographical basis in continental drift. The supercontinent Pangaea and its breakup explain many biogeographical puzzles. Phylogeny has a biogeographical basis in continental drift. The supercontinent Pangaea and its breakup explain many biogeographical puzzles. Mass extinction- followed by grand episodes of adaptive radiation. Mass extinction- followed by grand episodes of adaptive radiation.