Test Review
1. In a population that is in Hardy-Weinberg equilibrium, the frequency of the recessive
homozygous genotype is 0.09. The frequency of individuals homozygous for the
dominant allele is (1.) 0.7 (2.) 0.21 (3.) 0.42 (4.) 0.49 (5.) 0.09
2. In a certain African tribe, 4% of the population is born with a severe form of sickle cell
anemia. What percentage of the tribe enjoys the selective advantage of the sickle-cell
gene by being more resistant to malaria than individuals who are homozygous for
"normal" hemoglobin? (1.) 4% (2.) 16% (3.) 20% (4.) 32% (5.) 80%
3. Most of the genetic variation observed in large natural populations arises from (1.) new
mutations (2.) migration of individuals into and out of the population (3.) recombination
due to sexual reproduction (4.) genetic drift (5.) differential predation upon members of
the population
4. The most important kind of selection acting upon a well-adapted population in a
relative constant environment is (1.) directional selection (2.) stabilizing selection (3.)
disruptive selection
5. According to the Hardy-Weinberg Law, in the absence of natural selection and
mutation, and if the population experiences no migration, is very large, and has random
mating, which of the following statements is most correct? (1.) Evolution of the
population will continue at a normal rate. (2.) The makeup of the population's gene pool
will remain virtually the same indefinitely. (3.) The makeup of the population's gene pool
will change rapidly in a predictable manner. (4.) Homozygosity will slowly increase in
the population. (5.) The dominant genes in the population's gene pool will slowly
increase in frequency while recessive alleles will decrease.
6. Suppose a characteristic of a species varies gradually from one end of the species range
to the other geographical end of this range. This would be an example of (1.)
polymorphism (2.) polyploidy (3.) genetic drift (4.) a cline
7. The process in which a population moves into a relatively unexploited environment
and then undergoes rapid evolutionary divergence to produce many separate species is
called (1.) adaptive radiation (2.) convergence (3.) phylogeny (4.) disruptive evolution
(5.) punctuated equilibrium
8. Convergent evolution could cause a taxonomist (a student of classification) to assume
mistakenly that (1.) two unrelated species are closely related (2.) two closely related
species are unrelated (3.) members of different subpopulations of the same species are
unrelated
The terms below deal with speciation. For questions 9 through 12, match the appropriate
term from the list below to the sentences.
Choices: (1.) sympatric speciation (2.) allopatric speciation (3.) reproductive isolation
(4.) geographical isolation (5.) genetic drift
9. Two plant species can often hybridize. The hybrid progeny may become self-fertile
through polyploidy, giving rise to a distinct new species.
10. By chance an allele may be eliminated from a population's gene pool.
11. Two large populations once exchanged genes via sexual reproduction. Now if they
hybridize, the progeny are infertile.
12. A large population of animals is split in two by a physical barrier. The gene pools of
the two resulting populations then diverge until each population becomes a separate
species.
13. If the frequency of two alleles in the population A and a is 80 percent and 20 percent,
respectively, what will be the frequency of heterozygote individuals in the population?
(1.) 0.16 (2.) 0.32 (3.) 0.64 (4.) 0.40 (5.) 0.80
14. The idea that acquired characteristics are transmitted is most closely associated with
(1.) Darwin (2.) Wallace (3.) DeVries (4.) Mendel (5.) Lamarck
15. Red-haired persons tend to sunburn more easily than persons with dark brown hair.
This exemplifies Darwin's assumption that (1.) some phenotypes are selectively neutral
(2.) different phenotypes have different fitnesses (3.) the environment is a constant factor
in selection (4.) fitness is inherited
16. The example in question # 15 above also illustrates that (1.) a given trait may affect
an organism in several different ways (2.) the fitness of a population increases (3.) the
importance of a trait depends upon the environment (4.) none of these
17. The change of the coloration of the peppered moths is an example of verifying the
Darwinian theory by (1.) fossil record observations (2.) mathematical models (3.)
experimentation (4.) none of these
19. If there are two alleles for the same gene locus (1.) the more fit will drive the other to
permanent extinction (2.) a proportional balance will develop based on their ratios of
mutation and selection (3.) they will occur in a 1:1 ratio (4.) none of these
20. What is the founder principle (effect)? (1.) The principle that evolution is primarily
adaptive. (2.) The principle that genetic drift is unpredictable. (3.) The genetic drift that
results when a few members of a large colony population establish a new population in
an isolated spot (4.) The theory that separate populations begin with similar phenotypes
and change markedly, but always resemble each other.
21. Placentals and marsupials that look structurally alike are good examples of (1.)
convergent evolution (2.) mutations (3.) adaptive radiation (4.) mimicry (5.) parallel
evolution
22. Two different species live in nearly identical habitats. Over time they have evolved
markedly, becoming more similar. They have undergone (1.) genetic drift (2.) parallel
evolution (3.) convergent evolution (4.) none of these
23. Geographic isolation allows for the development of new species because (1.)
individuals from separate populations are infertile (2.) it takes a long time for barriers to
develop (3.) the environment of the separated population differ enough to select alleles
differently (4.) none of these
24. Geographical isolation is a prime cause of (1.) species extinction (2.) speciation (3.)
genetic drift (4.) infertility
25. As ancient cells became more crowded in the "primordial soup", the first major
competition was probably for (1.) sunlight (2.) oxygen (3.) organic molecules (4.) water
(5.) sexual partners
26. The first true organisms on earth probably depended entirely on fermentation for the
production of ATP, because aerobic respiration (1.) occurs in eukaryotes, but the earliest
organisms were prokaryotes (2.) could not occur until the evolution of water-based
photosynthesis had given rise to atmospheric oxygen (3.) could only oxidize
carbohydrates, while the earliest nutrients were mostly of other types (4.) occurs only in
animals, but the earliest organisms were plants (5.) could not arise until after the
evolution of a DNA-based genetic control system
27. Which one of the following statements is FALSE? (1.) The earliest living cells were
heterotrophic. (2.) If we could examine some of the earliest cells microscopically, we
would classify them in the kingdom Monera. (3.) The earth's primitive atmosphere was
probably an oxidizing one, but the metabolic activity of early organisms converted it into
a reducing one. (4.) Coacervate droplets have a marked tendency to incorporate various
substances from the surrounding medium. (5.) Many scientists believe that the
mitochondria evolved from bacteria.
28. The idea that mutations are the source of variations was first proposed by (1.)
Weismann (2.) Mendel (3.) Fox (4.) Miller (5.) DeVries (6.) Darwin (7.) Lamarck
29. Which is a basic assumption of the heterotroph hypothesis? (1.) More complex
organisms appeared before less complex organisms. (2.) Living organisms did not appear
until there was oxygen in the atmosphere. (3.) Large autotrophic organisms appeared
before small photosynthesizing organisms. (4.) Autotrophic activity added molecular
oxygen to the environment.
30. Weismann's experiments with mice produced results that helped to (1.) support
Darwin's assumption of a struggle for survival (2.) disprove Lamarck's theory (3.)
disprove the concepts put forth by DeVries (4.) support the theories of Miller and Fox
Questions 31 through 40 will be scored at a rate of one point per correct response.
The following listing of events in statements 31 through 35 relate to the heterotroph
hypothesis and early evolution. Place the number one before the earliest event, two
before the next event in the sequence, etc...
31. Polymerization of small organic molecules.
32. Great rains to form the ancient oceans.
33. Formation of the early earth and its atmosphere.
34. Abiotic synthesis of small organic molecules.
35. Formation of molecular aggregates and primitive cells.
Sequence the events indicated in statements 36 through 40. These statements also relate
to the heterotroph hypothesis and early evolution. Place the number one before the
earliest event, two before the next event in the sequence, etc...
36. Increasing oxygen levels in the atmosphere.
37. Evolution of many biochemical pathways and complex life activities in first
prokaryotic cells.
38. Reproduction and evolution of a genetic control system in primitive cells.
39. Evolution of photosynthesis.
40. Eukaryotic cell.
Use the following information to assist you in answering questions 41 through 43 below.
The following refer to the following events. In the year 2468, 2 male space colonists and
3 female space colonists settle on an uninhabited Earth-like planet in the Andromeda
galaxy. The colonists and their offspring mate randomly for many generations. All 5 of
the original colonists had free ear lobes, and 2 were heterozygous. The allele for free ear
lobes is dominant over attached ear lobes.
41. Assuming the Hardy-Weinberg equilibrium applies on this planet, about how many
people will have attached ear lobes when the planet's population reaches 10,000 people?
(1.) 0 (2.) 400 (3.) 800 (4.) 1000 (5.) 10,000
42. If 2 of the original colonists died before they produced offspring the ratios of the
genotypes could be quite different in the following generations. This is an example of:
(1.) diploidy (2.) gene flow (3.) genetic drift (4.) artificial selection (5.) stabilizing
selection
43. After many generations, the population on this planet had an unusually high
frequency for the incidence of colorblindness. This is most likely due to: (1.) founder
effect (2.) sexual selection (3.) coadapted genes (4.) introgression (5.) polyploidy
44. The wings of birds and butterflies are _________ structures.
(1.) homologous (2.) complimentary (3.) analogous (4.) allopatric
45. Charles Darwin and _________ proposed the theory of natural selection.
(1.) Wil Farrell (2.) Charles Lyell (3.) Alfred Wallace (4.) William Smith
46. One prediction of evolutionary theory is
(1.) mammals should appear in the fossil record after reptiles (2.) humans evolved from
monkeys
(3.) features acquired during an organism's lifetime are inheritable (4.) species are fixed
and immutable
47. Who is the author of the 'Theory of inheritance of acquired characteristics'?
(1.) Charles Darwin (2.) Jean Baptiste de Lamarck (3.) Alfred Wallace (4.) George
Mendel
48. The idea that evolution occurs rapidly giving rise to new species in few thousand
years is the
basis of ______________________ concept. (1.) specialization (2.) phyletic
gradualism
(3.) rapid counterbalance (4.) punctuated equilibrium
49. All of the following statements concerning the theory of natural selection are true
except:
(1.) Organisms produce far more offspring than are required for replacement.
(2.) The individuals in a population show variability in survivability and in their ability
to cope with environmental stress.
(3.) The number of offspring that survive to reproduce varies amongst individuals.
(4.) The bodies of organisms in a population change by use and disuse, and the changes
are inherited by the next generation.
(5.) Some of the variation in adaptation is the result of genetic differences that may be
passed on to the next generation.
Essays
1. Describe the process of speciation. Include in your discussion the factors
that may contribute to the maintenance of genetic isolation. Include in your
discussion the concepts of introgression, polyploidy, and at least one
prezygotic and one postzygotic isolating mechanism. Also explain how
geographic isolation may lead to allopatric speciation.
2. Do the following with reference to the Hardy-Weinberg model.
a. Indicate the conditions under which allele frequencies (p and Q) remain
constant from one generation to the next. (at least four of them)
b. Calculate, showing all work, the frequencies of the alleles and frequencies
of all the possible genotypes in a population of 100,000 rabbits of which 4,000
are white and 96,000 are agouti. (In rabbits the white color is due to a
recessive allele, w, and agouti is due to a dominant allele, W.)
3. Evolution is one of the unifying concepts of modern biology. Explain
the mechanisms that lead to evolutionary change. Describe how
scientists use each of the following as evidence for evolution:
1 Bacterial resistance to antibiotics
2 Comparative biochemistry
3 The fossil record
4. In a laboratory population of diploid, sexually reproducing organisms a certain trait is
determined by a single autosomal gene and is expressed as two phenotypes. A new
population was created by crossing 51 pure-breeding (homozygous) dominant individuals
with 49 pure breeding (homozygous) recessive individuals. After four generations, the
following results were obtained.
NUMBER OF INDIVIDUALS
Generation
1
2
3
4
5
Dominant
51
280
240
300
360
Recessive
49
0
80
100
120
Total
100
280
320
400
480
a) Identify an organism that might have been used to perform this experiment, and
explain why this organism is a good choice for conducting this experiment.
b) On the basis of the data, propose a hypothesis that explains the change in the
phenotype frequency between generation 1 and generation 3.
c) Is there evidence indicating whether or not this population is in
Hardy-Weinberg equilibrium? Explain