evolution ii1 what is the evidence for evolution? (chapter 21) observations of evolution and...
TRANSCRIPT
Evolution II 1
What is the evidence for evolution?(Chapter 21)
• Observations of evolution andArtifical selection
• Fossils
• Anatomic evidence
Question
Evolution II 2
Observations of evolution
Peppered moths-- Industrial melanism-- and its reversal
Evolution II 3
Other Examples
Corn ( ~ 9 K yrs )
Banana moths in Hawaii (1000 yrs)
Faroe Island house mouse (250 yrs)
Copapod of the Salton Sea, CA (30 yrs)
Drosophila paulistorum (a few yrs in a lab)
Evolution II 4
Paleontology
What does the fossil record show?Extinct life forms
Sequential appearance ofderived characteristics
Transitional forms
What are some limitations of the fossil record?
HabitatGeologic disruption Soft-bodied organisms
Ambulocetus natans (c. 50 Ma) – which means "walking whale that swims
Question
Evolution II 5
How are fossils dated?
Principle of “superposition”-- relative dating
Radioisotope dating (absolute dating)half-life14C 14N -- 5,730 years
(useful to ~ 60K yrs BP)
234U 230TH, ~ 80,000 years
40K 40Ar ~ 1.3 Billion yrs
Question
Evolution II 6
Anatomical evidence
What type of evidence doesanatomy reveal?
Derived traits have similar anatomy“homologous structures”
But “Convergent evolution’ occursindependent evolution“analogous structures”
Why does this occur?
Distinguishing homologous andanalogous traits is not always easy
A platypus has fur, a bill, webbed feet, and lays eggs
Question
Evolution II 7
Anatomical Evidence, con’t.
What does this mean:“Ontogeny reciprocates Phylogeny”?
Ernst Haekel’s original datais somewhat flawed
What are vestigial structures?
What are vestigial genes?-- gene for stripes in horses-- genes for teeth in birds
See Wikipedia for other cool exampleshttp://en.wikipedia.org/wiki/Vestigial
Human coccyx
Evolution II 8
Anatomical Evidence, con’t.
Intelligent design – not!
Human pelvis
External Testis
Eye?
Why?
Human coccyx