evidence for evolution (cont’d)
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
Evidence for Evolution (Cont’d)
1. The Fossil Record2. Biogeography 3. Anatomy4. Embryology 5. Molecular Biology6. Artificial Selection (last class)
Watch this: http://www.youtube.com/watch?v=faRlFsYmkeY
3. Anatomical Evidence
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)
Homologous Body Structures• similar structures inherited from a
common ancestor that have different functions in modern species
metacarpals
humerus
ulna
radius
phalanges
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 ancestorAnalogy: 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 organs: evolutionary baggage
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
Which is the human embryo?
Answer: All of them except the one above, which is a pig.
PIG FETUS
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
Number of amino acid differences betweenhemoglobin (146 aa) of vertebrate species and that of humansNumber of amino acid differences betweenhemoglobin (146 aa) of vertebrate species and that of humans
100 20 30 40 50 60 70 80 90 100 110 120
LampreyFrogBirdDogMacaqueHuman
328 45 67 125
STSE- A Chickenosaurus ?!
"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."
Hans Larsson, Canada Research Chair in Macro- Evolution at Montreal's McGill University
http://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.
Btw, if I were still alive, I would be wearing pink today
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