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Evidence for Evolution (Cont’d). 1. The Fossil Record 2. Biogeography 3. Anatomy 4. Embryology 5. Molecular Biology 6. Artificial Selection (last class) . Watch this: http://www.youtube.com/watch?v=faRlFsYmkeY. 3. Anatomical Evidence. Homologous Body Structures.
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Evidence for Evolution (Cont’d) 1. The Fossil Record 2. Biogeography 3. Anatomy 4. Embryology 5. Molecular Biology 6. Artificial Selection (last class) Watch this: http://www.youtube.com/watch?v=faRlFsYmkeY
Homologous Body Structures • Helps biologists group animals according to how recently they shared a common ancestor • Dolphins look more like fish but their homologies show they are mammals. They have lungs rather than gills and obtain oxygen from air, not water. (evolved from land mammals, not fish)
humerus ulna radius metacarpals phalanges Homologous Body Structures • similar structures inherited from a common ancestor that have different functions in modern species Similar in number and arrange-ments
Analogous Body Structures • Structures of organisms that are not from a common ancestor but perform similar functions These wings are for flying but have different structures
Homology vs. Analogy Homology: traits inherited by two different organisms from a common ancestor Analogy: similarity due to convergent evolution, not common ancestry
Vestigial organs - remains of a structure that was once functional (e.g. human tailbone) • The presence of the organ does not affect its ability to survive and reproduce, so natural selection does not eliminate it • demonstrates evidence of change over time Cave fish with no eye Pig feet- toes never touch the ground
Vestigial Structures • Examples: wings on flightless birds, human coccyx and appendix The appendix, for instance, is believed to be a remnant of a larger, plant-digesting structure found in our ancestors.
4. Evidence from Embryology • All vertebrates embryos develop similarly • Similar genes that define their basic body plan • We have ‘tails’ as embryos
PIG FETUS Answer: All of them except the one above, which is a pig.
5. Evidence from Molecular Biology • All organisms use DNA and RNA to transmit genetic information • ATP is an energy carrier in all organisms. • Similar amino acid sequences in proteins Human and Chimp Karyotype idiogram
BIOCHEMICAL EVIDENCE DNA, Amino Acids, Cytochrome C, hemoglobin are similar in related organisms
Comparative hemoglobin structure Dog Human Macaque Bird Frog Lamprey 8 32 45 125 67 0 10 20 30 40 50 60 70 80 90 100 110 120 Number of amino acid differences between hemoglobin (146 aa) of vertebrate species and that of humans
STSE- A Chickenosaurus ?! Hans Larsson, Canada Research Chair in Macro- Evolution at Montreal's McGill University "If I can demonstrate clearly that the potential for dinosaur anatomical development exists in birds, then it again proves that birds are direct descendants of dinosaurs."
http://www.ted.com/talks/lang/en/jack_horner_building_a_dinosaur_from_a_chicken.htmlhttp://www.ted.com/talks/lang/en/jack_horner_building_a_dinosaur_from_a_chicken.html
To ponder: Adaptation? • http://www.youtube.com/watch?v=NOjFA4V_Ks4
Uhm, what evidence would falsify my evolution theory?Think about it kids.
Homework • Read pg. 296-302 • Pg. 303 #4-7 • Pg. 303 #1 and 2 Consolidation • Summarize the various kinds of evidence for evolution (i.e., that all living organisms descended from a common ancestor) • Remember: Population evolve; Individuals do not