Week 2 Lecture

1. Week 2 Lecture Evolution & Natural Selection Human Variation, Adaptation & Genetics: Covering the Basics Christine E. Haney*NWU*Anthropology 151*Fall 2005

2. Evolution • Creationism • Catastrophism • Uniformitarianism • Natural Selection “When I view all beings not as special creations, but as the lineal descendants of some few beings which lived long before the first bed of the Cambrian system was deposited, they seem to me to become ennobled.” Charles Darwin

3. Creationism & Other Religious “Creation Myths” Creationism is commonly taken from the Christian doctrine as explained in Genesis, the first book of the Bible. Many other religions throughout the world also have “creation myths” or beliefs about the beginnings of the world.

4. Timeline of Evolutionary Thought (see the Handout: Week 2 Timeline) • Francis Bacon • William Harvey • Georges L.L. Buffon • Erasmus Darwin • Jean Baptiste de Lamarck • Thomas R. Malthus • Georges Cuvier • Charles Lyell • Charles Darwin

5. Charles Darwin & the Beagle Just how old is the Earth and those who have lived upon it? Developing an expanded time-span. H.M.S. Beagle: Darwin joins crew in October 1831 and stayed on for five years and 40,000 miles. Plenty of time to read the classics and devise a new scheme: Natural Selection/Survival of the Fittest.

6. Darwin: Part II • Mutability of species • Some species go extinct while other, similar species go on. • Representative species over a continent • Islands resemble the nearest mainland • Those islands, however, are not (as expected) identical) • Alfred R.Wallace (1958) • On the Origin of Species (1959) • Darwin’s contribution

7. Human Heredity and Genetics • Lamarckism • Pangenesis • Gradual change versus Punctuated Equilibrium • Gregor Mendel • Basic Principles of Genetics

8. Punctuated Equilibrium Evolutionary theory that long periods of stasis (stability), during which species change little, are interrupted (punctuated) by evolutionary leaps.

9. Gregor Mendel(1822-1884) Discovered the principles of heredity while experimenting with pea plants in his monastery’s garden in the 1860’s. Through careful choice of contrasting traits, he was able to determine dominant vs. recessive traits & define chromosomes and genes (alleles)

10. Mendel’s Experiment

11. Segregation The traits do not “mix” or “blend” when the parents reproduce. The traits are inherited separately– e.g. Blood Type. IndependentAssortment Traits are not dependent upon one another. If your father has blonde hair and blue eyes and your mother brown hair and brown eyes, you need not have all of one and none of the other, but you may inherit a bit of both– brown hair and blue eyes. Mendelian GeneticsUnderstanding the Hereditary Mechanism

12. Evolution Evolution is simply: descent with modification: – Parents produce offspring who share common alleles – Occasionally mutations in parents arise – If these mutations enhance an offspring’s survival and reproduction, the offspring better adapted to the environment. – Through time, those individuals carrying adaptation become more common

13. Evolution: Two Key Concepts Natural selection: the process by which certain members of a population differentially contribute offspring to the next generation. Measured as reproductive success or fitness either as number of offspring or number of genetic equivalents. It is important to note that RS is a relative measure, relative to other individuals in the population and relative to specific environmental conditions. Adaptation: some individuals are able to make a higher relative contribution to the next generation in a population because they are better adapted to the environment (both social and natural). Adaptation can be defined as "any structure, physiological process, or behavioral pattern which makes an organism more fit to survive and reproduce in comparison to other members of the same species population."

14. Some Principles of Evolution • Organisms are designed to be reproductively selfish. • Altruism cannot exist if defined as assisting another to enhance his or her fitness while simultaneously reducing your own. • Fitness is relative to other members of the population. • Adaptations are never for the good of the group. • Adaptations develop in past environments. • Natural selection is not the only mechanism of evolutionary change. Other mechanisms include drift, bottlenecks, and founder’s effect. • Adaptations are seldom perfect: they are merely superior to previous solutions. • The environment determines which traits are useful. • Mutations are independent of the environment.

15. Ways of Being “Fit” • Efficient food acquisition • Resistance to disease • Detection and evasion of predators • Insulation from the elements and • sources of environmental trauma • Acquisition of high quality mates • Quality investment in offspring

16. Natural SelectionSurvival of the Fittest • Peacocks • Moths • Elephants • Giraffes • Finches

17. Adaptation and Selection inChanging Environments

18. Mutations- sickle cell anemia (pp 74) Random Genetic Drift- small populations Gene Flow- interbreeding within a species- assists in determining origin of species Adaptation Three adaptations to thin air Melanin- ultraviolet radiation- rickets Teeth & Noses (pp 94) Body size (San vs. Nuer vs. Inuit) Natural Selection & Adaptation

19. Cloning/Gattaca Gattaca

20. Why A Need To Know? Why is this information pertinent to Anthropology? Why does Natural Selection matter to Anthropologists?