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Flashcards in Exam 3 Deck (50)
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1

The hypothesis of neutral evolution asserts that
A) the rate of molecular mutation is influenced by natural selection.
B) most variability in the structure of molecules does not affect their functioning.
C) closely related species have more similar molecular structures than do distantly related species.
D) organisms evolved through neutral changes in their molecules.
E) mutations neither add nor subtract amino acids from molecules.

B. most variability in the structure of molecules does not affect their functioning.

2

A small population of sawflies that was once connected to a larger one but is now isolated is no longer experiencing
A) enhanced genetic drift.
B) gene flow.
C) reproductive isolation.
D) natural selection.
E) genotypic equilibrium.

B. gene flow

3

Mules are an example of which type of reproductive isolation?
A) Low hybrid zygote viability
B) Temporal isolation
C) Postzygotic isolation
D) All of the above
E) None of the above

C. Postzygotic isolation

4

The sizes of horns in males of a particular beetle have an interesting distribution: the highest frequencies are around 15 millimeters and 30 millimeters, with few individuals in between. Based on this observation, which of the following modes of selection is most likely to be operating on these horns?
A) Stabilizing selection
B) Directional selection
C) Concentrated selection
D) Disruptive selection
E) Purifying selection

D. Disruptive selection

5

Which type of speciation is most common among flowering plants?
A) Geographic
B) Sympatric
C) Allopatric
D) Disruptive
E) None of the above

B. Sympatric

6

Oxygen in Earth's atmosphere was
A) generated, in part, by photosynthetic cyanobacteria.
B) generated abiotically.
C) generated by nonphotosynthetic bacteria.
D) present in high amounts before the origin of life.
E) present in low amounts when larger eukaryotes evolved.

A. generated, in part, by photosynthetic cyanobacteria

7

In a hypothetical population of sawflies, 20 percent of the population is homozygous for allele A and 45 percent is homozygous for allele a. Assuming that A and a are the only alleles at this locus, what percent of the population is heterozygous?
A) 10 percent
B) 20 percent
C) 35 percent
D) 45 percent
E) Insufficient information is given to answer the question

C. 35 percent

8

The wasp genus Nasonia contains all of the descendants of the members' common ancestor. This genus therefore would be called
A) a synapomorphy.
B) a polyphyly.
C) a clade.
D) parsimonious.
E)self-compatible

C. a clade

9

Which of the following statements about biological evolution is false?
A) Species change over time.
B) Natural selection produces changes in species.
C) Individuals in a population evolve.
D) Different species may share a common ancestor.
E) Most populations are genetically diverse

C. Individuals in a population evolve

10

Which of the following is not a condition that must be met for a population to be at Hardy–Weinberg equilibrium?
A) Absence of gene flow
B) Absence of differential survival among genotypes
C) Random mating of individuals with respect to genotype
D) Absence of genetic drift that would cause chance fluctuations of allele frequencies
E) Small population size

E. small population size

11

An evolutionary trend toward shorter legs is observed in a rodent. Which of the following processes is the most likely explanation for this pattern?
A) Genetic drift
B) Stabilizing selection
C) Directional selection
D) All of the above
E) None of the above

C. directional selection

12

Random genetic drift would probably have its greatest effect on a
A) small, isolated population.
B) large population in which mating is nonrandom.
C) large population in which mating is random.
D) large population with regular immigration from a neighboring population.
E) large population with a high mutation rate.

A. small, isolated population

13

The experiments by Rice and Salt with fruit flies showed that
A) speciation can be studied in the lab.
B) the evolution of reproductive isolation requires more than one hundred generations.
C) acetyldehyde can be used to keep fly populations from becoming species.
D) Both a and b
E) Both a and c

A. speciation can be studied in the lab

14

Geographic isolation
A) Is the basis of allopatric speciation.
B) always results in the formation of new species.
C) is required for speciation.
D) does not cause a decreased probability, over time, that members of two separated populations can mate.
E) has the same effects on all organisms

A. is the basis of allopatric speciation

15

Despite being incomplete as a whole, the fossil record is rather detailed for
A) soft-bodied insects.
B) cnidarians and sponges.
C) most terrestrial animals.
D) hard-shelled mollusks.
E) Both c and d

D. hard-shelled mollusks

16

Gene duplication can
A) occur by duplication of an entire diploid genome.
B) result in the formation of pseudogenes.
C) result in genes that are lost from the genome.
D) lead to the evolution of genes that code for proteins with new functions.
E) All of the above

E. All of the above

17

Which of the following best describes natural selection?
A) Chance variations in traits
B) The differential survival and reproduction of individuals
C) The processes that lead individuals to resemble their parents
D) The potential for all species to increase rapidly in number
E) The immutability of species

B. the differential survival and reproduction of individuals

18

Genes from many isolates of the influenza virus have been sequenced. In certain regions of the genome, nonsynonymous substitutions have been found to occur much more frequently than synonymous substitutions. From this pattern we can infer that
A) a great deal of genetic drift is taking place.
B) most of the amino acid changes are neutral.
C) strong stabilizing selection is acting on this gene.
D) strong selection for change (directional selection) is acting on this gene.
E) mutations that change the amino acid are disadvantageous.

D. strong selection for change (directional selection) is acting on this gene.

19

Shared derived traits are also known as
A) homoplasies.
B) synapomorphies.
C) sympatries.
D) homologies.
E) paraphylies.

B. synapomorphies

20

If the half-life of a radioactive substance is 600 years, what fraction of the original material is left after 1,800 years?
A) One-half
B) One-fourth
C) One-eighth
D) One-sixteenth
E) None of the above

C. One-eighth

21

Suppose you were to drill a hole toward the center of Earth. Which of the following is the correct order of the layers you would encounter?
A) Magma, mantle, lithospheric plate
B) Mantle, magma, lithospheric plate
C) Lithospheric plate, magma, mantle
D) Lithospheric plate, mantle, magma
E) Mantle, lithospheric plate, magma

C. Lithospheric plate, magma, mantle

22

If variation at a given locus has no effect on the phenotype of individuals, which of the following evolutionary processes will still occur at that locus?
A) Genetic drift
B) Natural selection
C) Nonrandom mating
D) Both a and b
E) None of the above

A. Genetic drift

23

If a population with two alleles is at Hardy–Weinberg equilibrium and the frequency of one allele is 0.7, what is the heterozygote frequency?
A) 0.7
B) 0.42
C) 0.3
D) 0.21
E) Insufficient information is given to answer the question.

B. 0.42

24

What is the critical distinction between allopolyploidy and autopolyploidy?
A) Allopolyploidy involves disruptive selection.
B) Autopolyploidy involves disruptive selection.
C) The mode of speciation in allopolyploidy is allopatric rather than sympatric.
D) Autopolyploidy requires genetic contribution from two different parental species.
E) Allopolyploidy requires genetic contribution from two different parental species

E. Allopolyploidy requires genetic contribution from two different parental species

25

Which of the following is a likely reason for the diversification of Lake Malawai cichilds?
A) Habitat specialization
B) Male competition for females
C) Polyploidy
D) Both a and b
E) Both b and c

D. Both a and b

26

The artificial selection experiments with bristle numbers in Drosophila illustrate which of the following generalities?
A) In such experiments, it is difficult to obtain individuals with traits that fall outside the range found in the original population.
B) Populations often contain considerable genetic variation upon which selection can operate.
C) Such experiments usually take thousands of generations to achieve their results.
D) Mutations occur to suit the needs of the population.
E) None of the above

B. Populations often contain considerable genetic variation upon which selection can operate.

27

What was Darwin's explanation for the evolution of bright colors and other apparently useless (and potentially deleterious) but conspicuous characters in males of many species?
A) Stabilizing selection
B) Genetic drift
C) Sexual selection
D) Disruptive selection
E) Gene flow

C. Sexual selection

28

Which of the following is not a prezygotic reproductive isolating barrier?
A) Behavioral isolation
B) Mechanical isolation
C) Hybrid infertility
D) Temporal isolation
E) All of the above are prezygotic reproductive isolating barriers

C. Hybrid infertility

29

Most of human evolution has occurred during the
A) Paleozoic era.
B) Devonian period.
C) Quaternary period.
D) Carboniferous period.
E) Cretaceous period.

C. Quaternary period

30

Rocks that are formed when grains accumulate at the bottom of bodies of water are called _______ rocks
A) igneous
B) sedimentary
C) strata
D) tertiary
E) deep

B. sedimentary