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Evolution. Primer 1. A. What is it?. The change of living organisms over time. [1]. A. What is it?. 2. There were many naturalists in the 18th century whose proposed ideas about evolution. Linnaeus : classification system from kingdom to species
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Evolution Primer 1
A. What is it? • The change of living organisms over time. [1]
A. What is it? 2. There were many naturalists in the 18th century whose proposed ideas about evolution. • Linnaeus: classification system from kingdom to species • Buffon: species shared ancestors rather than arising separately • Erasmus Darwin: more-complex forms developed from less-complex forms • Lamarck: environmental change leads to use or disuse of a structure
Theories of geologic change set the stage for Darwin’s theory. • There were three theories of geologic change. • catastrophism • gradualism • uniformitarianism
B. Evidence for Evolution • Fossil • A whole organism or parts of an organism preserved or petrified -A mold or cast of an organism left in rock -An organism that became trapped in ice or amber (resin) [4] Primer 3 [2] [3]
B. Evidence for Evolution b) Fossils in older layers are more primitive than those in the upper layers.
B. Evidence for Evolution 2. Comparative Anatomy • The study comparing structures of different organisms • Homologous Parts • Similar in structure, in function, or both • More homologous structures shared by different kinds of organisms, the closer their relationship • Similarities in function alone cannot determine ancestry (Birds vs. Insects)
B. Evidence for Evolution 2. Comparative Anatomy • The study comparing structures of different organisms • Vestigial Structures • Structures once useful for an organism’s lifestyle but now has no function • The organism’s ancestors may have used them • Examples in humans: • Appendix (digestion) • Coccyx (tail) [6]
[1] Blind Salamander [7] Wisdom Teeth? [8]
B. Evidence for Evolution • b) Not all structures are evidence for evolution. • Analogous structures have a similar function but different ancestry. • Analogous structures are not evidence of a common ancestor. Mole foot
B. Evidence for Evolution 3. Comparative Embryology • Study of developing organisms • Shows the number of relationships not obvious in grown organisms (Overhead)
B. Evidence for Evolution 4. Comparative Biochemistry • Study of organisms on a biochemical level • Compares Amino Acid Sequences [9]
B. Evidence For Evolution 5. Genetic Evidence • Mutations • Scientists look at DNA sequences • Selective Breeding 7. Direct Observations • Mosquitoes vs. Deet [11] Primer 6