15-3 evolution in process. evidence of evolution 1. homologous structures 2. analogous structures 3....
TRANSCRIPT
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