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15-3. Evolution in Process. Evidence of Evolution. 1. Homologous Structures 2. Analogous Structures 3. Vestigial Structures 4. Similarities in Embryology 5. Similarities in Macromolecules . 1. Homologous Structures. Similar features that originated in common ancestor (recent)
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15-3 Evolution in Process
Evidence of Evolution • 1. Homologous Structures • 2. Analogous Structures • 3. Vestigial Structures • 4. Similarities in Embryology • 5. Similarities in Macromolecules
1. Homologous Structures • Similar features that originated in common ancestor (recent) • Ex: human arm, bird wing, frog arm
2. Analogous Structures • Features which share a purpose but do not have common origin • Ex: bird wing insect wing
3. Vestigial Structures • Features which were useful to an ancestor but have no current use • Ex: • Human tail bone, appendix • Snake pelvic bones limb bones • Whale pelvic bones
4. Similarities in Embryology • “Ontogeny recapitulates phylogeny” • Embryological development repeats evolutionary history • Ernst Haeckel
5. Similarities in Macromolecules • Amino acid sequence (proteins) • Ex cytochrome C • The more similarities = the more recent common ancestor
Patterns of EvolutionWays in Which Species Change • 1. Coevolution • 2. Convergent evolution • 3. Divergent evolution
1. Coevolution • Change of 2 or more species in close association with each other • Ex predator/prey flowers/pollinators
2. Convergent Evolution • Occurs when similar phenotypes in different species are selected in similar environment even though ancestors were very different • Ex shark & porpoise
3. Divergent Evolution • Occurs when 2 or more related populations or species become more & more different (usually due to habitat changes) • 2 types • Adaptive radiation • Artificial selection
Adaptive Radiation • Many species from single common ancestor • Ex Darwin’s finches
Artificial Selection • Selective breeding • Ex dogs, cats, horses, sheep, chickens, fruit