Biology 160 Final Exam Notes

1. Biology 160 Final Exam Notes An Introduction to Evolutionary Biology and Ecology

2. ABO Blood Groups I Red blood cells have surface markers (often referred to as antigens). Although there are many kinds of these markers, three of them are of major clinical importance resulting in the ABO and Rh blood groups.

3. ABO Blood Groups II A and B are both dominant over O but A and B are codominant with each other. Thus the possible ABO blood types are A, B, O, and AB. Note that a person can have either two A alleles or one A allele and one O allele and still be type A.

4. ABO Blood Groups III Because a person with type A blood has anti-B, a blood transfusion of type B blood would be potentially fatal. This is because the person’s antibodies will attack the foreign blood cells and cause what is called a transfusion reaction. Likewise a person with type B blood cannot get type A blood and a person with type O blood cannot get types A, B, or AB. However, there is no reaction when people with type A or type B blood get blood of type O. Notice that the person who is type AB can get any other type.

5. Rh Blood Group I Most individuals possess the D surface marker (Rh antigen) and thus would not make anti-D. About 15% of caucasians do not have the D surface marker and upon exposure to Rh+ blood, they will produce anti-D. If one of the Rh - persons were to get two transfusions with Rh+ blood they could have a transfusion reaction..

6. Rh Blood Group II An additional problem occurs when an Rh- mom is pregnant with an Rh+ fetus. When the mom and baby blood mix (usually during birth), the mom’s body will start producing anti-D. However, this will not harm the mom or that child. But if the mom becomes pregnant with a second Rh+ child, the anti-D will cross the placenta and attack the fetal rbcs. This can cause the death of the child or a very serious condition called hemolytic disease of the newborn or erythroblastosis fetalis. Fortunately the mom’s immune system can be fooled into thinking it produced anti-D if she receives rhogam during her pregnancy and shortly after delivery

7. Evolution is often defined as change over time but we will expand the definition to: the change in allele frequencies in a population over time. The proposed mechanism for evolution (by Charles Darwin and Alfred Russell Wallace in the 1850s) is Natural Selection.

8. Darwin had read the work of several other scientists including Thomas Malthus who pointed out that populations tend to increase exponentially (if unlimited resources are available), but do not because of limited resources and Charles Lyell who pointed out that competition between species leads to a “struggle for existence”.

9. Wallace and Darwin then proposed Natural Selection which is based on the potential of every organism to produce more offspring than actually survive and that individuals who possess superior physical, behavioral, or other attributes are more likely to survive than those that are not so well endowed. Thus the survivors pass on these favorable traits and these characteristics increase in the population and eventually the population changes.

10. Controversies related to Evolution Creationism/Evolution Intelligent design/Evolution Mechanisms of Evolution e.g., punctuated equilibrium Natural Selection/Sexual Selection Units of Selection Etc.

11. Evidence in support of evolution by natural selection

12. Fossils I the existence of fossils of extinct species that resemble extant species occurring in the same area

13. Fossils II changes in the fossils of different layers of rock revealed progressive changes

14. Comparative Anatomy similarities in more closely related organisms (comparative anatomy)

15. Embryossimilarities in embryos of different species as well as the structures (e.g., tails and gill slits) that occur in human embryos.

16. Biogeography geographic distributions of organisms e.g., the marsupials of Australia that are ecological equivalents of placental mammals elsewhere

17. Island species the uniqueness of species on islands (in relation to continental species) and the similarities (in relation to other species on the same or geographically close islands)

18. Current examples of evolution that we have documented including Kettlewell’s work with the peppered moth and antibiotic resistance in many bacterial species.

19. Factors necessary for Natural Selection units of selection, sources of variation, and types of selection

20. Factors 1. characteristics must be inherited 2. there must be variation in these characters 3. there must be an excess of offspring produced 4. differential reproductive success of those offspring must occur.

21. Units of selection. What level does selection act upon?

22. Gene selection Gene selection involves differential survival of genes within an individual There is some evidence supporting this in a few cases and it makes sense since evolution is defined as the change in allele frequencies over time. But an individual is a complex organism that contains many genes.

23. Individual selection In general this is the most accepted of the units of selection. The individual survives and reproduces or does not. Previously infanticide like this was thought of as supporting Group selection, but that is no longer the case

24. Kin selection Kin selection occurs when related individuals help other kin raise offspring or give up their own fitness for that of a relative. In order for this to work, kin must be able to recognize each other. In addition, the closer the relationship the more likely it is that kin selection will occur

25. Group selection Group selection describes natural selection acting upon groups of organisms, rather than individuals (Ridley, 2004). Many instances of what look like group selection are actually selection upon the individual

26. Sources of variation

27. Mutation

28. Independent assortment during Meiosis

29. Crossing over during meiosis

30. Sexual Reproduction

31. Gene flow

32. Patterns stabilizing- selection favors mean directional- selection favors a shift in the mean disruptive- selection against the mean

33. The Hardy-Weinberg Equilibrium Equation p2 + 2pq + q2 = 1 where: p = the frequency of the allele A q = the frequency of the allele a and p2 = AA, 2pq = Aa, and q2 = aa

34. Assumptions: no mutation large population size isolated populations (no gene flow) sexual reproduction with random mating no selection

35. Does this seem realistic? Of course not. Moreover nonequilibrium supports evolution because evolution is the change in allele frequencies (in a population) over time and nonequilibrium is a change in allele frequencies.

36. Genetic drift adds chance to the evolutionary process

37. Founder effects occur when a limited number of individuals migrate to a previously uninhabited (for that species) area and begin or found a population. Because fewer individuals established that population, a decrease in variation is possible.

38. Bottlenecks are severe reductions in population size that result from some catastrophe. Again variation is reduced. Cheetahs appear to have gone through a population bottleneck many years ago and as a result, may soon be extinct despite our efforts to save them. This is also a major concern for conservation biologists because humans are causing severe reductions in the population sizes of many other species.

39. Sexual Selection is defined as differential reproduction resulting from variable success in obtaining mates Darwin also proposed this

40. Intrasexual selection male/male competition, female/female competition

41. Intersexual selection or mate choice. In many species, random mating does not occur females choosing males is most common because of the differential input into offspring, males choosing females does occur in some species, but is associated with situations where males put large investments (energy wise) into the offspring.