Evolution…day 1

1. Charles Darwin Alfred R. Wallace Thomas Huxley Gregor Mendel Theo. Dobzhansky R.A. Fisher J.B.S. Haldane Stephen J. Gould Evolution…day 1 Barbara McClintock

2. Schedule • Feb 5:     Natural Selection & Evolution  • Feb 7:     Phylogenetics & Major Transitions (assignment due Feb. 14:  Phylogeny Problem and Topic selection for paper) • Feb. 12:   Documentary OR day off with an evening viewing of the documentary?? Schedule? • Feb. 14:   Origins of Life • Feb. 19    Origins of Structure & Adaptation • Feb. 21    Origins of Species

3. Great Ideas (Pyles!): Assignments • Problem in Phylogenetics • Instructions Thursday Feb. 7 • Can be completed individually or pairs (2 only per team) • DUE Feb. 14th (happy valentines’ day) • Paper on Evolution (individual) • Instructions on Thursday Feb. 7 • Topics (your topic selection due Feb. 14): • Homo sapiens: X = evidence of bad design? • Evolution of the group X • Evolution of the characterisic X • Propose something (but no politics, please) • DUE March 11

4. When analyzing a scientific explanation, which of the following is most important? • Logic • Data • Source (i.e., scientific standing of the author or institution) • Hypothesis • All of the above

5. FREE FLOW ….

6. The best definition of the process of EVOLUTION is: • Survival of the fittest. • Origin of new species from existing species. • Different individuals leave behind different numbers of offspring. • Selection of new traits in a species from environmental pressures. • Humans descended from chimps in Africa. • The Strong eventually eliminate the Weak. • A steady march of progress from microbes to man.

7. Natural Selection • Some characteristics of individuals are heritable • Some individuals will have higher survival rates • Some individuals will have higher reproduction (more offspring = higher fecundity) • If heritable characteristics are linked to those individuals with higher fecundity… • THEN, the next generation will have “more” of those advantageous heritable characteristics Thus, differential reproduction of individuals with heritable characteristics will shift the genetic “profile” of the population, increasing those advantageous traits in the next generation…and so on, and so on…

8. Modern Synthesis: Evolution Differential reproduction (aka natural selection) can shift the genetic profile of organisms over time. Are there any other phenomena that can also affect the genetic profile of a group of organisms over time? YES!

9. Modern Synthesis: Evolution • Genetics: • Mutations • Chromosomal changes • Duplication of a gene or genes • Incomplete reproductive isolation (“hybrids”) • Population size or composition • Immigration or loss of “portions” of original group • Emigration from “outside” sources • Nonrandom mating • Historic Contingency • Random events (e.g., huge meteors! disease! Fast climate change!, etc.)

10. Modern Synthesis: Evolution Natural Selection Genetic mechanisms Population size or composition Nonrandom mating Historic Contingency

11. Misconceptions HOW IT WORKS! • Evolution is progressive • Evolution is random • Organisms “try” to adapt • Natural selection gives organisms what they ”need” • Gaps in the fossil record disprove evolution • Evolution cannot be observed or tested

12. Scalae naturae (Aristotle)

13. Survivors { Origins & Extinctions Darwin’s concept of “tree of life” (1859)

15. TETRAPODA

16. Which came first…?? Of the following pairs, which came first historically? • FISH or AMPHIBIANS • MOSS or FISH • DINOSAURS or BIRDS • BEES or FLOWERS • EUKARYOTIC or PROKARYOTIC cells • CELLS or VIRUSES

17. Misconceptions HOW IT WORKS! • Evolution is progressive • Evolution is random • Organisms “try” to adapt • Natural selection gives organisms what they ”need” • Gaps in the fossil record disprove evolution • Evolution cannot be observed or tested

18. Misconceptions • Random? • Sometimes yes… • Mutations and genetics “jumps” (e.g., gene duplication) • Historic contingencies • Sometimes no… • Natural selection is NOT random • Nonrandom breeding is not…well, you know

19. Misconceptions HOW IT WORKS! • Evolution is progressive • Evolution is random • Organisms “try” to adapt • Natural selection gives organisms what they ”need” • Gaps in the fossil record disprove evolution • Evolution cannot be observed or tested

20. Misconceptions • Organisms can “think” ahead NOPE! • Giraffes can’t get longer necks by “stretching” • Giraffes with longer necks get more food and are able to reproduce more offspring They don’t “think” their way there… • Nature can “think” ahead NOPE! Nature can’t predict what will happen next METEOR!!…RUN! And, oh by the way…scientists can’t predict either!

21. Misconceptions HOW IT WORKS! • Evolution is progressive • Evolution is random • Organisms “try” to adapt • Natural selection gives organisms what they ”need” • Gaps in the fossil record disprove evolution • Evolution cannot be observed or tested

22. Gaps? A A A A Z Z Z Z = 2 gaps B B B C C = 3 gaps D = 4 gaps = one gap “Shanks paradox” named for the author… At least a little logic is a requirement for any argument.

23. Misconceptions HOW IT WORKS! • Evolution is progressive • Evolution is random • Organisms “try” to adapt • Natural selection gives organisms what they ”need” • Gaps in the fossil record disprove evolution • Evolution cannot be observed or tested

24. Misconceptions • Science is not restricted to controlled experiments. • Astronomers cannot hold stars in their hands, • Geologists cannot go back in time, • Epidemiologists don’t create epidemics to study them. But in all cases scientists can learn a great deal by using multiple lines of evidence to make valid and useful inferences about their objects of study.