Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Evidence for Evolution Chapter 22 What you need to know! 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 role of adaptations, variation, time, reproductive success, and heritability in evolution. Types of Evidence 1. 2. 3. 4. Evidence for evolution is provided by 5 scientific principles Direct observations The fossil record Homology Biogeography Direct Observations Manchester Peppered Moth Wild guppies w/ plain colors The common cold and flu Drug resistant bacteria and viruses Fossil Record Paleontology is the study of fossils Fossils are remains or traces of life in sedimentary rock Substantial, but incomplete, chronicles of evolutionary history Transitional fossils have been found that link ancient organisms to modern species Coincides with biogeographical understanding (continental drift) Fossil Record Homology Def: traits in related species can have underlying similarity w/ different function Homologous Structures: • structural similarity of body due to common ancestry • functionally dissimilar Homology 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 Homology Molecular homology includes a variety of similarities: All organisms share the same genetic code (DNA/RNA triplets/codon The closer related a species, the higher the percentage of identical DNA • Chimp and human DNA is 98% identical • Bird and Human DNA is only 60% identical • Plant and Human DNA is only 10% identical Homology Convergent Evolution: unrelated species around the world look similar when found in similar environments (analogous structures) Biogeography Def: geographic distribution of 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 species Continental drift explains the similarity of species on different continents Endemic species are species unique to one specific environment (marine iguanas)