Evidence for Evolution Chapter 22

What you need to know! Several examples of evidence for evolution. Several examples of evidence for evolution. The difference between structures that are homologous and those that are analogous, and how this relates to evolution. The difference between structures that are homologous and those that are analogous, and how this relates to evolution. The role of adaptations, variation, time, reproductive success, and heritability in evolution. The role of adaptations, variation, time, reproductive success, and heritability in evolution.

Types of Evidence Evidence for evolution is provided by 5 scientific principles Evidence for evolution is provided by 5 scientific principles 1. Direct observations 2. The fossil record 3. Homology 4. Biogeography

Direct Observations Manchester Peppered Moth Manchester Peppered Moth Wild guppies w/ plain colors Wild guppies w/ plain colors The common cold and flu The common cold and flu Drug resistant bacteria and viruses Drug resistant bacteria and viruses

Fossil Record Paleontology is the study of fossils Paleontology is the study of fossils Fossils are remains or traces of life in sedimentary rock Fossils are remains or traces of life in sedimentary rock Substantial, but incomplete, chronicles of evolutionary history Substantial, but incomplete, chronicles of evolutionary history Transitional fossils have been found that link ancient organisms to modern species Transitional fossils have been found that link ancient organisms to modern species Coincides with biogeographical understanding (continental drift) Coincides with biogeographical understanding (continental drift)

Fossil Record

Homology Def: traits in related species can have underlying similarity w/ different function Def: traits in related species can have underlying similarity w/ different function Homologous Structures: Homologous Structures: structural similarity of body due to common ancestrystructural similarity of body due to common ancestry functionally dissimilarfunctionally dissimilar

Homology Embryonic homologies are the notable anatomical similarities in the embryonic development of animals Embryonic homologies are the notable anatomical similarities in the embryonic development of animals

Homology Vestigial Structures: anatomical structures that ancestors used but now have reduced (or no) function Vestigial Structures: anatomical structures that ancestors used but now have reduced (or no) function

Homology Molecular homology includes a variety of similarities: All organisms share the same genetic code (DNA/RNA triplets/codon All organisms share the same genetic code (DNA/RNA triplets/codon The closer related a species, the higher the percentage of identical DNA The closer related a species, the higher the percentage of identical DNA Chimp and human DNA is 98% identicalChimp and human DNA is 98% identical Bird and Human DNA is only 60% identicalBird and Human DNA is only 60% identical Plant and Human DNA is only 10% identicalPlant and Human DNA is only 10% identical

Homology Convergent Evolution: unrelated species around the world look similar when found in similar environments (analogous structures) Convergent Evolution: unrelated species around the world look similar when found in similar environments (analogous structures)

Biogeography Def: geographic distribution of species Def: geographic distribution of species Species tend to be more related to nearby species Species tend to be more related to nearby species i.e. desert animals in South America are more related to local animals in other habitats than to African desert speciesi.e. desert animals in South America are more related to local animals in other habitats than to African desert species Continental drift explains the similarity of species on different continents Continental drift explains the similarity of species on different continents Endemic species are species unique to one specific environment (marine iguanas) Endemic species are species unique to one specific environment (marine iguanas)