EXAM, 2ND BIOL 164, GENETICS, EVOLUTION & SOCIETY, SPRING 2007 NAME (Last/Family Name First): Signature: Student ID Number: ________________________________ ________________________________ ________________________________
Instructions: Circle the correct answer, or circle the letter corresponding to the correct answer, or write in the correct answer, as appropriate. In all cases, write legibly; answers that I cannot read will be considered incorrect. All questions are of equal point value. Good luck! ~~~~~~~~~~~~~~~~~~~~~~~
1. A population of pea plants has two flower color alleles, red and white. Red is dominant to white. What is the frequency of red flower alleles in a population of 1,000 pea plants in Hardy-Weinberg equilibrium, if there are 160 pea plants with white flowers?
______________ q2 = 0.16, so white, q, = 0.4, and red, p, = 0.6.__________________
2. A small, captive breeding program for rhinos in a zoo has only 8 individuals. What assumption of Hardy-Weinberg does this population violate? Infinite population size (inbreeding/random mating also accepted) _________________________________________________
3. For mutant alleles (i.e., those that have amino acid substitutions), natural selection guarantees that the beneficial alleles and the deleterious (harmful) alleles found in populations will most often be of what types? a. Dominant and dominant, respectively. b. Dominant and recessive, respectively. c. Recessive and dominant, respectively. d. Recessive and recessive, respectively.
4. You are a CSI on your way to court to testify. Your boss tells you that the suspect in the case is a homozygote at locus X and is a match to a sample at the crime scene, but then his cell phone loses contact with yours. You are familiar with locus X, and know it has 3 alleles; the frequencies are, p = 0.7, q = 0.2, and r = 0.1. What are the chances of sampling a homozygote from the general population at locus X? (Assume people are a random mating population.) ____ p2 + q2 + r2 = (0.7*0.7)+(0.2*0.2)+(0.1*0.1) = 0.54_____ ("pqr" is not a diploid genotype!)
5. For some trait in a particular plant species, say number of leaves per branch, in which population would you expect to measure higher heritability - a population raised in a carefully controlled greenhouse or a wild population inhabiting an edge habitat between a forest and a field? Greenhouse Wild The greenhouse population, because there is less environmental variation.
6. There are two flower color alleles at a particular locus in the Irish flag-flower. One homozygote had green flowers, the other homozygote has orange flowers, and the heterozygote has white flowers. If you had to choose from among the following terms for the way the genotypes produce the phenotypes in this species, which would be the best description? a. Complete dominance b. Incomplete dominance c. Epistasis (can't be; only one locus involved per question) d. Mutation
7. Has this population experienced natural selection? YES Genotype Number at birth Number at reproduction Survival Relative fitness AA 360 72 20% 1 Aa 480 96 20% 1 aa 160 32 20% 1
NO
8. Why do prey species have more dramatic adaptations than predator species? a. The outcome of any given attempt at predation has higher fitness consequences for the prey than the predator. b. The outcome of any given attempt at predation has higher fitness consequences for the predator than the prey. c. Prey species tend to be smaller in body size and have higher population sizes than their predators. d. Prey species occupy narrower ecological niches than their predators.
9. How fast a swimmer does natural selection tend to make a fish? a. Very, very fast b. Faster than its physiological limits c. As fast as hydrodynamically possible d. Just faster than the shark that eats it
10. The hard, domed shells of turtles have been around for roughly two hundred million years and are "well-designed", in a biomechanical sense, for resisting the powerful, crushing jaws of their main predators, crocodilians (alligators and relatives), who have also been around for roughly two hundred million years. Turtle shells are also very good at preventing modern mammalian carnivores, e.g., coyotes, from eating turtles. Are turtle shells an adaptation to predation by mammals? YES NO (Adaptation to crocs; mammals hadn't evolved when shells arise)
11. The `handicap principle', also called `truth in advertising', means that male birds with bright feathers and long tails will be MORE or LESS healthy than male birds with dull plumage and short tails.
12. JBS Haldane is reputed to have quipped in a pub that he would lay down his life for two brothers or eight first cousins. Let's improve on Haldane's off-the-cuff remark. Would it be best (in the genetic sense only) for him to lay down his life if those eight cousins were all: a. Sons of his father's brother b. Sons of his father's sister c. Sons of his mother's brother d. Sons of his mother's sister e. Daughters of his father's brother f. Daughters of his father's sister g. Daughters of his mother's brother h. Daughters of his mother's sister (everyone in "a" has same Y chromosome)
13. Why is extreme altruism (eusociality) so prevalent in the Hymenoptera (bees, ants, and wasps)? a. They live in large groups. b. They build elaborate nest, hives, etc. c. They are have aneuploid sex determination. d. They have haplodiploid sex determination.
14. The sex with the higher level of parental investment per offspring is more likely to with mate relatively FEW or MANY individuals of the opposite sex.
15.
During the evolution of horses from Hyracotherium (formerly called Eohippus) to Equus, which of the following happened: a. Increase in body size b. Reduction of number of toes c. Change in cheekteeth to long, harder d. Grasslands evolved e. All of the above
16. The phenomenon of sympatric populations of two species being more different in appearance than allopatric populations of the same two species (e.g., island populations of finches, anoles, etc.) is called "character displacement". For either of the competing species, what pattern of natural selection does competition with the similar sympatric species create in each species? a. Disruptive selection b. Stabilizing selection c. Directional selection (each species evolves away from the other) d. All of the above e. Neither a) nor b) nor c)
17.
Placental mammals in separate lineages in South America and Africa have both evolved into digging forms that specialize on tearing apart and feeding on ant and termite mounds (anteaters and pangolins); in open forests of North America and Australia a placental mammal (flying squirrel) and a marsupial (flying phalanger) have evolved membranes for gliding from tree to tree. This is best described as: a. convergent evolution b. divergent evolution c. gradual evolution d. phenotypic evolution e. punctuated evolution
18.
The analogy between exotic species and genetically modified organisms (GMO's) flows from the idea that species are adapted to one anothers' presence in the environment. The large & rapid phenotypic changes (particularly of the biochemical phenotype) that occur via genetic engineering are rather like taking an organism out of its original environment and placing it in a new one. What are possible consequences of this? a. For the vast majority of such genetically modified organisms, probably no noticeable environmental ill effects. b. Escaped genes, e.g., pesticide resistance, via hybridization with wild relatives, e.g., in the mustard family. c. Creating new susceptibility of the genetically modified organisms to pests via the addition of genes that produce critical nutrients. d. All of the above.
19.
The maintenance of the sickle-cell anemia allele of hemoglobin occurs because of the disease organism, Plasmodium falciparum (malaria). The name for this mechanism and its relative importance as a mechanism for maintaining genetic diversity within species in nature is: a. heterozygote advantage, often important b. heterozygote advantage, rarely important c. homozygote advantage, often important d. homozygote advantage, rarely important
20.
Frequency-dependent selection (also called negative frequency-dependent selection) maintains genetic variation in populations when the fittest phenotypes are: a. best camouflaged b. most common c. least common d. aposematic & poisonous
21.
The following forces can contribute to the evolution of prezygotic isolating mechanisms between two different populations that can lead to speciation: a. Spatial variation in natural selection b. Genetic drift (chance) c. Mutation d. Lack of migration/gene flow between them e. All of the above
22.
The maxim, "Plurality should not be posited without necessity", is called: a. Occam's Razor b. Gillette's Razor c. Straight's Razor d. Norelco's Razor
23.
When analyses of different data sets (e.g., morphology, DNA, behavior) yield the same pattern of relationships among species, it is called... a. ...congruence. b. ...convergence. c. ...parsimony. d. ...analogy.
24.
It would be nearly impossible to argue that vestigial traits (traits for which organisms appear to have no use), such the degenerate pelvic girdles ("hip bones") of pythons and whales, were examples of anything other than: a. Homology b. Tautology c. Reinforcement d. Parsimony
25.
What is DNA's greatest strength as a data source for inferring the genealogy of life? _______________ Comparability across any taxa_________________
26.
The relationships of the major groups of living things are understood to be related phylogenetically as below:
If you were to erect a taxon, "Unicellularia", composed of single-celled organisms (Bacteria, Archaea, Protists), would it be monophyletic? YES NO
27.
Answer ONE of the following: What important morphological innovation allowed organisms to stop laying their eggs in water? Or....
In what geological period did this important morphological innovation evolve? Amnion; Carboniferous _________________________________________________
28. a. b. c. d. e.
What major evolutionary process began roughly 130 million years (MYR) ago? "Cambrian explosion"/diversification of body plans Origin & diversification of flowering plants Extinction of the dinosaurs Invasion of land by plants & insects Invasion of land by vertebrates
29. What caused the extinction of the dinosaurs? a. Impact of a large boloid in what is now Mexico b. Extreme volcanism in what is now Siberia c. Massive viral epidemics d. Time-traveling trophy hunters
30.
Below is a phylogeny of the plants (outgroup not shown). The data table shows the distribution of derived traits or character states of each species (1's). Which characters display convergent evolution (or reversals, or parallel evolution, as you prefer)? There are two (C, F). Character\Species A B C D E F G H I Moss 0 0 0 0 0 0 0 0 1 Fern 1 0 0 0 0 0 0 1 1 Pine 0 1 1 0 0 1 1 1 1 Palm 0 1 0 0 1 1 1 1 1 Oak 0 1 1 1 1 0 1 1 1