BSC 2011 (Periods 3 and 5; Spring 1997)

Answers to Exam III

Correct answers are given as the first option after each question (i.e., preceded by "AA S")


QQ Based on Figure 1, the most recent common ancestor for species C and E had what character states:

AA S (1) derived state for characters a and d; all others ancestral.

(2) derived state for characters a, d, e, f; all others ancestral.

(3) derived state for characters a, b, c, d; all others ancestral.

(4) derived state for characters a, d, e, f, g; all others ancestral.

(5) none of these.

QQ Refer to Figure 1. Species A and B each possess the "0" state for character e. This is called a:

AA S (1) ancestral homology.

(2) derived homology.

(3) analogy.

(4) reversion.

(5) convergence.

QQ Refer to Figure 1. Which group is monophyletic?

AA S (1) CDE

(2) BCD

(3) ABC

(4) BCDE

(5) ABCD

QQ Which of the following is an acceptable definition of evolution?

AA S (1) a change in the genetic makeup of a population

(2) a change in the phenotypic makeup of a population

(3) a change in the environmental conditions

(4) a change in the genotypic makeup of an individual

(5) a change in the species composition of a community

QQ Anatomical structures that show similar function but dissimilar embryonic and evolutionary background are said to be

AA S (1) analogous.

(2) primitive.

(3) homologous.

(4) monophyletic.

(5) polyphyletic.

QQ Evolution by natural selection requires all of the following EXCEPT:

AA S (1) Acquired (non-genetic) traits must be passed on to offspring.

(2) There must be phenotypic variation in the population.

(3) Phenotypic variation must have a heritable component.

(4) Fitness of different phenotypes must be different (on average).

(5) There must be genetic variation in the population.

QQ Kettlewell's study of the English peppered moth, Biston betularia, illustrated that the effect of natural selection depends on the

AA S (1) environment.

(2) sexual selection.

(3) intensity of melanin.

(4) principle of common descent.

(5) presence of homologies among moths.

QQ Which of the following is most likely to have been produced by sexual selection?

AA S (1) a male lion's mane.

(2) eye spots on a butterfly fish.

(3) the ability of desert animals to concentrate their urine.

(4) different sizes of male and female pine cones.

(5) cryptic coloration in animals that are eaten by visual predators.

QQ When we say that one organism has greater fitness than another, we mean that it

AA S (1) leaves more viable offspring.

(2) has greater aerobic capacity.

(3) mates more frequently.

(4) utilizes resources more efficiently.

(5) lives longer.

QQ Two male and three female space colonists settled on an uninhabited planet in the Andromeda galaxy. The colonists and their offspring randomly mated for many generations. 300 years later, a biologist visited the planet and saw that all the people had blue eyes and attached ear lobes, and correctly concluded that these traits evolved via:

AA S (1) the founder effect and were not adaptations.

(2) natural selection because the traits attracted mates.

(3) natural selection because the traits increased survivorship.

(4) genetic drift because the traits were highly advantageous.

(5) phenotypic plasticity.

QQ The only taxonomic category that actually exists as a discrete unit in nature is the

AA S (1) species.

(2) genus.

(3) family.

(4) class.

(5) phylum.

QQ Which of the following statements is consistent with the punctuated equilibrium interpretation of speciation?

AA S (1) Long periods of minor change; short bursts of major change.

(2) Evolution proceeds at a slow, steady pace.

(3) Rapid speciation is caused by population explosions.

(4) There is an equilibrium between living and extinct species.

(5) Large populations evolve more quickly than small ones.

QQ A botanist discovers a large population of annual plants. The plants all look basically the same, but seem to be of two different size classes. The larger and smaller plants inhabit the same areas and are visited by the same pollinating insects. Under what conditions might the two sizes of plants be considered two different species?

AA S (1) Pollen from either morph fails to germinate on the other.

(2) Pollinating insects prefer the larger plant to the smaller.

(3) Tests show some genetic differences between the plants.

(4) Crosses between the two morphs yield hybrids of intermediate size.

(5) Bigger plants have bigger cells and other phenotypic differences.

QQ The biological species concept is inadequate for grouping

AA S (1) asexual organisms.

(2) parasites.

(3) plants.

(4) endemic populations.

(5) sympatric populations.

QQ Two subspecies, A and B, are not considered separate species even though they cannot interbreed when brought together. The most likely reason is:

AA S (1) gene flow between A and B occurs through other subspecies.

(2) A and B have eliminated postzygotic but not prezygotic barriers.

(3) A and B are endemic to isolated geographic regions.

(4) Gene flow has ceased and genetic isolation is complete.

(5) Their diploid gametes are produced by nondisjunction.

QQ The ostrich and the emu look very similar and live in similar

habitats, although they are not very closely related. This is an

example of

AA S (1) convergent evolution.

(2) divergent evolution.

(3) co-evolution.

(4) adaptive radiation.

(5) sympatric speciation.

QQ According to the hypothesis known as species selection, an evolutionary trend results from

AA S (1) varying rates of speciation and extinction among clades.

(2) paraphyletic groupings of endemic species.

(3) stepwise progression of a single, unbranched lineage.

(4) phyletic evolution that gradually transforms a single population.

(5) a drive toward perfection.

QQ Animals that help other animals of the same species are expected to

AA S (1) be genetically related to the other animals.

(2) be bigger and stronger than the other animals.

(3) have excess energy reserves.

(4) be female.

(5) have defective genes controlling behavior.

QQ Gene flow between two populations

AA S (1) makes the populations more similar.

(2) facilitates speciation.

(3) speeds up the divergence of two populations.

(4) increases the genetic variation between populations.

(5) none of these.

QQ Male northern sea lions are nearly twice the size of females because

AA S (1) males compete with other males for access to females.

(2) predators of the sea lions favor males.

(3) males live longer than females.

(4) each male must protect the one female with which he mates.

(5) bigger size confers a feeding advantage.

QQ Which of the following would NOT distinguish two different species?

AA S (1) Their biogeographic ranges do not overlap.

(2) If hybrids are produced, the offspring are sterile.

(3) They have distinct gene pools.

(4) Their courtship patterns are different so they don't mate.

(5) Male and female genitalia of different species are incompatible.

QQ Which of the following can result in instant speciation?

AA S (1) polyploidy

(2) development of a physical barrier between populations

(3) elimination of gene flow due to geographic isolation

(4) change in environmental conditions

(5) the introduction of a new predator into an area

QQ The similarity in external morphology of sharks, penguins, and porpoises is due to

AA S (1) convergent evolution.

(2) co-evolution.

(3) shared ancestral traits.

(4) a suite of identical genes in all three groups.

(5) their descent from a common ancestor (i.e., "fish").

QQ Cladistics (or phylogenetics) is preferred over phenetics because cladistics focuses on

AA S (1) common ancestry.

(2) behavior.

(3) phenotypic similarity.

(4) taxonomy.

(5) analogous structures.

QQ Which of the following can be used as an outgroup for comparison to the others?

AA S (1) coelocanth (fish)

(2) blue jay (bird)

(3) tree frog

(4) alligator

(5) humans

QQ A ground squirrel sees a falcon and issues an alarm call. As a result of this call, the falcon is able to orient toward the caller and capture it. Why does calling behavior persist in this ground squirrel species?

AA S (1) The behavior is maintained via kin selection.

(2) The behavior is not acted on by natural selection.

(3) Calling behavior is genetically based.

(4) Some of the time, falcons do not capture the caller.

(5) Other ground squirrels benefit from the call.

QQ Which of the following can help bring about major macroevolutionary changes:

AA S (1) all of these.

(2) the evolution of traits that serve as preadaptations.

(3) a change in the growth rate of some structures relative to others.

(4) heterochrony.

(5) a change in a regulatory gene, which alters morphology.

QQ The Principle of Parsimony

AA S (1) requires choosing the tree with the fewest evolutionary steps.

(2) is used because evolution occurs by the simplest series of steps.

(3) is not useful because several trees can be equally parsimonious.

(4) is the most powerful tool used in the phenetic approach.

(5) is preferred over phenetics because it gives the correct phylogeny.

QQ The response to selection will be greatest when:

AA S (1) heritability is high and there is strong selection.

(2) heritability is high but selection is not too intense.

(3) a few males mate with many females

(4) survivorship and fecundity are both high.

(5) there is stabilizing selection.

QQ Two snail populations (that inhabit two different lakes) have different shell thicknesses. These differences could be due to:

AA S (1) all of these.

(2) differences in water chemistry which affect shell deposition.

(3) a developmental response to the presence of predators.

(4) evolution driven by presence/absence of shell-crushing predators.

(5) genetic drift resulting from the colonization of these lakes.

QQ Endler and Reznick separated the effects of phenotypic plasticity from evolution by:

AA S (1) raising guppies from each site under the same conditions.

(2) sequencing the DNA of guppies from different streams.

(3) looking at the size-selectivity of Crenicichla and Rivulus.

(4) monitoring guppy populations over many generations.

(5) all of these.

QQ If a structure grows isometrically,

AA S (1) its shape remains constant as its size changes.

(2) its shape changes as it changes in size.

(3) it requires exercise to alter the muscle and bone morphology.

(4) its shape is transformed into the adult morphology.

(5) it cannot be studied evolutionarily.

QQ Habitats that are rich in food are often associated with greater risk to predation. This is an example of:

AA S (1) a trade-off

(2) an optimal foraging model

(3) a sexual conflict

(4) a synapomorphy

(5) a fixed action pattern

QQ Measuring heritability can be problematic due to

AA S (1) all of these.

(2) maternal effects.

(3) environmental effects.

(4) gene by environment interactions.

(5) transfer of non-genetic material from a mother to her offspring.

QQ Cooperative behavior can be maintained through all of the following except:

AA S (1) reciprocity between strangers

(2) group selection (a la D.S. Wilson)

(3) kin selection

(4) reciprocity between non-relatives

(5) haplodiploidy


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