Major Objectives

1. Major Objectives 1. Understand the historical context for evolutionary theory, including Darwin's field research that helped frame his view of life 2. Define Darwinism and Darwin's main ideas from the Origin of Species 3. Discuss examples of natural selection and other evidence for evolution

2. "Nothing in biology makes sense except in the light of evolution." Theodosius Dobzhansky

3. What is Evolution?? Change in gene frequency in a population over time

4. Evolution was resisted by Western culture -Greek philosophers: Aristole (scala naturae) -Natural theology (1700's)

5. Ladder of Life

6. Lamarkian Evolution

8. Figure 22.3 Formation of sedimentary rock and deposition of fossils from different time periods

9. Figure 22.2 Fossils of trilobites, animals that lived in the seas hundreds of millions of years ago

10. Figure 22.4 Strata of sedimentary rock at the Grand Canyon

13. Galapagos Island Finches: Beaks Differed According to Food Supply

14. Darwin's Intellectual Revolution

16. Millions of DNA Switches That Power Human Genome's Operating System Are Discovered ScienceDaily (Sep. 5, 2012) — The locations of millions of DNA 'switches' that dictate how, when, and where in the body different genes turn on and off have been identified by a research team led by the University of Washington in Seattle. Genes make up only 2 percent of the human genome and were easy to spot, but the on/off switches controlling those genes were encrypted within the remaining 98 percent of the genome.

18. In the mid-1990s, researchers were surprised to discover that fruit flies, mice, and humans who were born missing eye structures had defects in the same gene. This gene, called Pax6 (or eyeless in flies), is required for normal eye development in all animals with bilateral symmetry. Even in eyes that look very different, Pax6 functions in much the same way. When placed in a fly, the mouse Pax6 gene activates all the genes necessary to form a normal, functional fly eye (not a mouse eye).

20. What the Encode project tells us about the human genome and 'junk  ENCODE, the Encyclopedia of DNA Elements, is the most ambitious human genetics project to date. It takes the 3 billion letters described by the Human Genome Project in 2000, and tries to explain them.  http://www.youtube.com/watch?v=Y3V2thsJ1Wc http://www.youtube.com/watch?v=UBQ5a7mCpMs

21. Darwinism has a dual meaning -Evolution as the explanation for life's unity and diversity (descent with modification) -Natural selection as the cause of adaptive evolution

22. Figure 22.7 Descent with modification

23. Darwin's main ideas from "The Origin of Species"

24. Artificial Selection-selecting desired traits

25. 1. Natural selection is differential success in reproduction Idea of overreproduction influenced by Thomas Malthus (1798)

26. 1. Differential success in reproduction Not All Organisms Get To Mate Why is this important?

27. 2. Natural selection occurs through an interaction between the environment and the variability inherent among the individual organisms making up a population Why is this important?

28. 3. The product of natural selection is the adaptation of populations of organisms to their environment How does this result in population change?

29. How does natural selection work?

30. Peppered Moths: Real Natural Selection Example • Original population: white in color, blended into lichens on trees • During industrial revolution, lichens died & trees covered in soot • Lighter moths had higher predation rates, darker moths had high survival rates • Over time, population became dominated by dark moths

32. Darwin’s Theory of Natural Selection: Favorable traits that are heritable become more common in successive generations of a population, and unfavorable traits that are heritable become less common If phenotypes have a genetic basis, phenotypes will increase or decrease in frequency Results in change in gene frequency over time

33. Darwin’s Theory Lacked Satisfactory Theory of Heredity • Modern Synthesis (1920-1940): • Unification of Mendel’s theory of heredity and Darwinian evolution

34. Evidence for Evolution

35. Evidence for Evolution Fossil Record Natural selection Homologous structures Molecular Biology-DNA Islands Vestigial Organs Convergent Evolution

36. Same skeletal elements, different functions

38. 500 endemic species

39. Vestigial Organs

40. Convergent Evolution- The independent development of similarity between species as a result of their having similar ecological roles and selection pressures

41. Major Objectives 1. Do populations or organisms evolve? 2. What are the major differences between microevolution and macroevolution? 3. What are the four main factors that can alter genetic diversity? 4. Identify the three main modes of natural selection. 5. Describe the four main reasons why natural selection cannot produce perfection.

43. Populations Evolve, Natural Selection Occurs at the Level of Organisms

44. Types of Evolution *Microevolution-A change in the gene pool of a population from generation to generation *Macroevolution-Evolutionary change on a grand scale, encompassing the origin of new taxonomic groups, evolutionary trends, adaptive radiation, and mass extinction

45. Four Main Factors That Can Alter Genetic Diversity 1) Genetic Drift A change in a population’s genetic diversity due to chance

47. Why are small populations so vulnerable to extinction?

48. Extinction Vortex Disturbance lowers population size Reduced Genetic Variability Reduced ability to survive environmental stochasticity

49. Founder Effect—example for higher risk of breast or ovarian cancer in women

50. Four Main Factors That Can Alter Genetic Diversity 1)Genetic Drift 2) Natural Selection Differential success in reproduction