BEFORE YOU BEGIN: Make sure you have 6 different pages of questions and an answer sheet.  Put your name and student id number (social security number) on the front of the answer sheet.  Answer all questions on the answer sheet (not the exam); when you are done you should turn in only the answer sheet (which will be returned to you once it is graded) and keep the exam to use for future studying.

MULTIPLE CHOICE/ FILL-IN: Answer the following questions by writing the letter corresponding to the correct answer (for multiple choice) or the terms or brief explanations required for fill-in questions in the numbered space corresponding to the question number on your answer sheet.  This section of the exam is worth 86 points (each multiple choice or fill-in question is worth the same amount toward these 86 points.)

1. Which of the following is NOT one of the characteristics of a population that results in natural selection?
a. more young are produced each generation than will survive to reproduce
b. population size is small
c. there is variation in the population
d. individuals in the population are genetically different from each other
e. some individuals in the population have traits that result in higher fitness compared to other individuals

2. The general term for genetic change in populations over time is ____________________

3. A trait that has evolved through natural selection is called a(n): _____________________

4. The degree to which individuals with certain traits survive and reproduce is called __________________

5. Evolution that occurs through random change changes in the frequency of alleles existing in a population is called __________________________

6. Natural selection that occurs when both extreme forms of a continuously variable trait have high fitness, and intermediates have low fitness, is called ____________________ selection.

7.  Evolution that occurs because individuals move from population to population is called ________________________

8. Once a gene for antibiotic resistance is present in a population of bacteria,
a. it will evolve to become common through natural selection in environments with antibiotics present
b. it will evolve to become common through genetic drift in environments with antibiotics present
c. it will spread to other species of bacteria but not become common within the population because genes for antibiotic resistance are only spread to bacteria of different species
d. it will evolve to become common in the population of bacteria, but will not spread to other bacterial species, since bacteria pass antibiotic resistance only to their own offspring, not to other species

9. PBPs:
a. are enzymes break down penicillin
b. are circles of DNA that are not part of the bacterial chromosome, on which genes for penicillin resistance can be transferred among bacteria
c. are pieces of DNA that are picked up from the environment and incorporated into the chromosome of a bacterium
d. are proteins involved in making the cell wall of bacteria, to which penicillin can bind and prevent cell wall synthesis in many bacteria

10.  In a population of turtles, more young hatch from eggs each generation than can survive to reproduce.  The turtles differ in shell thickness; some have thin shells and some have thick shells.  Thick shelled turtles are less likely to be eaten by predators than are thin shelled turtles.  Briefly state the one additional thing you need to know about this population to know that natural selection will occur ________________________________________

11.  Which of the following is/are NOT true of natural selection?
a. it occurs so that traits that benefit species will evolve
b. it causes evolutionary change within populations
c. it decreases the amount of genetic variation within populations
d. two of the above
e. all of the above

12.    In a population of mice, fur length varies continuously: some mice have short fur, many have medium length fur, and some have long fur.  In these mice, individuals with short fur do not survive well because they are not well insulated against the weather, and individuals with long fur can not run well to escape from predators because they trip over their fur, but individuals with medium length fur survive and reproduce well.  Assuming that natural selection is affecting this trait, this example illustrates:
a. directional selection
b. stabilizing selection
c. sexual selection
d. disruptive selection
e. genetic drift

13.  In the population of mice described in the previous question, over time, assuming natural selection is affecting fur length, you would predict that:
a. on average, fur length will become longer
b. the average fur length will stay the same and the amount of variation in fur length will increase
c. on average, fur length will become shorter
d. the average fur length will stay the same and the amount of variation in fur length will decrease
e. the average fur length will stay the same and the amount of variation in fur length will stay the same

 14.  In a population of lizards, males have bright colors; females do not.  Bright color in males has evolved because it increases mating success, even though brightly colored males are more likely to attract predators.  The form of evolution responsible for the evolution of these bright colors is in males is:
a. directional selection
b. stabilizing selection
c. sexual selection
d. disruptive selection
e. genetic drift

15.  The two main ways in which the form of evolution you chose in the previous question to explain how bright coloration in lizards evolves are:
a. competition for mates and attraction of mates
b. the traits increase survival and increase mating success
c. mutation and random change in frequency of traits in the population
d. transformation and plasmids

16. Loss of genetic variation in populations
a. occurs through genetic drift
b. occurs through natural selection
c. is occurring in animals used as livestock because of the way most people breed these animals
d. two of the above
e. all of the above

17. -19.  We observe loss of genetic variation in populations of endangered species that occurs because populations of endangered are small.  The form of evolution that results in loss of variation in small populations, although it has little impact on large populations, is (17)__________________.  Two  reasons that this loss of genetic variation may make it harder to conserve these endangered species are (18) _____________________________ and (19)__________________________

20.  A form of evolution that is expected to add genetic variation to a population quickly enough so that it can counteract the loss of genetic variation that is occurring in endangered species is:
a. mutation
b. natural selection
c. gene flow
d. genetic drift
e. stabilizing selection

21.  State one action that people managing endangered species can take to cause the form of evolution that you chose in the previous question to occur: ___________________________________

22. The principle of uniformitarianism, as applied to evolutionary biology, states that:
a. evolution has been occurring at a constant rate throughout time
b. evolution occurs in the same way in all different species
c. since evolution can be observed in modern populations, it has probably occurred under similar conditions in the past, so it can explain the origin of the various forms of life
d. since evolution can be observed by examining the constant changes among forms of fossils in the fossil record, it must be true

23.  Which of the following lines of evidence most directly suggests that it is possible for enough genetic differences to evolve within one species so that two new species can be created from that one species?
a. the existence of the ring species of Ensatina salamanders
b. the fact that humans have been able to breed golden retrievers from some wolf-like ancestor
c. the fact that peppered moths changed from being gray in color to being black in color over generations after their environment changed
d.  the fact that genetic variation is changing in domesticated chickens over time

24.  A group of animals called "arthropods" all have a hard outer skeleton.  Within this group, another group, the insects, all have six legs in addition to the hard outer skeleton.  Within the insects, another group, the beetles, all have a hardened cover over their wings as well as having six legs and a hard outer skeleton.  This pattern illustrates:
a. the existence of ring species
b. genetic changes occurring within populations
c. prezygotic reproductive isolation
d. the hierarchical pattern of homology
e. postzygotic reproductive isolation

25. - 27.  State ONE way in which a barrier could arise to geographically isolate two populations from each other at the start of allopatric speciation:(25) _________________________.  This barrier is important to the process of speciation because it prevents a form of evolution that would make speciation unlikely if it did occur; this form of evolution is called (26)________________________.  Briefly state why this form of evolution would make speciation unlikely if it did occur (27)_______________________________________

28.  Two species of flowering plant are reproductively isolated because pollen is produced by one species only during May but flowers of the other species do not open, and can not be pollinated, until September.  Is this an example of prezygotic or postzygotic reproductive isolation? (answer with one of the underlined terms) ______________________________

29.  Do the following two trees represent the same or different phylogenies? (answer with one of the underlined terms) ____________________________

 30. - 32. Answer the following questions with regard to the following phylogeny (this is based in part on a recent study of mammalian evolutionary relationships).

30.  According to this phylogeny, whales are most closely related to which other species?
a. sheep
b. cow
c. hippo
d. pig

31.  The point where the ancestor to whales speciated from the ancestor to pigs is indicated by which roman numeral on the tree?
a. i
b. ii
c. iii
d. iv
e. v

32. The ancestor to the sheep and the cow, but no other species on the tree, is indicated by which roman numeral on the tree?
a. i
b. ii
c. iii
d. iv
e. v

33.  The evolution of different species in response to one another is called ________________

34. We are currently genetically engineering some crop plant species to have toxins  (poisonous substances) that poison insects.  Based on what we know of insect and plant  evolution
a. these should be effective indefinitely, since plants that have evolved toxins against insects naturally have remained protected from being eaten by insects as a result of these toxins
b. these should be effective indefinitely; even though insects have evolved to resist pesticides they will not resist these genetically engineered toxins because they are inside of plant leaves rather than applied to the outside of the leaves
c. these are likely to become less effective with time because we expect plants to evolve to lose these unnatural toxins since there is no benefit to having them
d. these are likely to become less effective with time because we expect insects to evolve through natural selection to resist these toxins, just as they have evolved to resist many natural plant toxins and many pesticides

 35.  Wombats are marsupial (pouched) mammals.  They are distantly related to woodchucks, but wombats and woodchucks have independently evolved large incisors good for eating large nuts and seeds.  This independent evolution of similar traits in these distant relatives is an example of _____________________________

36.  The form of microevolution most likely responsible for the independent evolution of large incisors good for eating large nuts and seeds in wombats and woodchucks is:
a. genetic drift
b. sexual selection
c. gene flow
d. natural selection

LONGER ESSAY: Answer the following on the BACK of your answer sheet.

37. Describe how bacteria can transfer genes for penicillin resistance to other bacteria that are NOT their offspring.  In your answer, explain what a plasmid is and what transformation is; be sure to make it clear how these are relevant to gene transfer among bacteria.  Then explain how this ability to transfer genes affects how penicillin resistance evolves within a species and how it can spread among species -- how is this different from what happens as evolution occurs in species that are NOT bacteria?

38. In "Dying Breeds" by Raloff, it is argued that even through Holstein cattle produce most milk, other forms of dairy cattle should be conserved.  Give two potential problems discussed in the paper that might occur if other forms of dairy cattle are allowed to go extinct.  Could the same kinds of problem also apply to natural populations of wildlife where genetic variation is lost? Why or why not?