EXAM 4. BIOLOGY 1406
Ch 12, 14, 15, 16.
1) Snapdragons have a single gene (locus)
that determines flower color. The allele
R is for red flowers and it shows
incomplete dominance over the
recessive allele r for white flowers.
What color flowers are produced by Rr
plants?
a) All red
b) Mixed red and white (some flowers
of each color)
c) Pink
d) white with pink streaks
e) purple
2) An allele at one locus affects several
phenotypic traits (e.g. cystic fibrosis is
caused by a single defective gene which
causes clogged blood vessels, sticky
mucus, salty sweat, liver failure, etc.).
This is an example of:
a) continuous variation.
b) codominance.
c) incomplete dominance.
d) epistasis.
e) pleiotropic effects.
3) A human autosomal recessive lethal
genetic disease whose defective allele
has been maintained at a relatively high
level in certain population groups
because it gives the heterozygote
resistance to malaria is:
a) Tay-Sachs disease.
b) cystic fibrosis.
c) sickle-cell anemia.
d) muscular dystrophy.
e) Huntington’s disease.
4) An inactivated ‘X’ chromosome in a
human female cell is seen as a/an:
a) centrosome.
b) Barr body.
c) genetic imprint.
d) nucleosome.
e) centromere.
5) The human chromosomes which are not
either the "X" or "Y" chromosomes are
collectively called _________.
a) Mosaics
b) sex chromosomes
c) karyotypes
NAME __________________________
d) monosomics
e) autosomes
6) A human gene is said to be sex-linked if:
a) it is more common in females than
males.
b) it is found on the ‘Y’ chromosome.
c) it is encoded by the ‘X’
chromosome.
d) it is expressed only in males.
e) it is recessive in males
7) A person with a karyotype of trisomy 21
will suffer from:
a) Tay-Sachs.
b) Down Syndrome.
c) Kleinfelter Disease.
d) Huntington Disease.
e) Turner Syndrome.
8) A trait shows continuous variation within
a population (e.g. height in humans).
This suggests that the trait exhibits:
a) a polygenic pattern of inheritance.
b) pleiotrophy.
c) incomplete dominance.
d) codominance.
e) linkage disequilibrium
9) If the allele for inflated pea pods (I) is
dominant to the allele for constricted (i),
the cross Ii x ii is expected to produce
a) all with inflated pods.
b) All with constricted pods.
c) half with inflated and half with
constricted pods.
d) 3/4 with inflated and 1/4 with
constricted pods.
e) 3/4 with constricted and 1/4 with
inflated pods.
10) A recessive gene is one
a) that is not expressed as strongly as
a dominant allele.
b) whose effect is masked by a
dominant allele.
c) that appears only in a heterozygote.
d) that produces no effect when
present in the homozygous
condition.
e) that must be lethal in the
homozygous condition.
11) The physical manifestation
(appearance) of an organism's genes is
its
a) environment.
b) genotype.
c) phenotype.
d) genetic code
e) number of chromosomes.
12) A phenotypic ratio of 9:3:3:1 indicates
that we are dealing with an example of
___________ using a __________
cross.
a) Segregation, Monohybrid.
b) Segregation, Dihybrid.
c) Independent assortment,
monohybrid.
d) Independent assortment, dihybrid.
13) The incorrect theory that "organisms can
modify their bodies through use or disuse of
parts, and that these modifications can be
passed on to their offspring" was formulated
by
A) Hutton.
B) Darwin.
C) Aristotle.
D) Lamarck.
E) Lyell.
14. Structures that may differ in function but
that have similar anatomy, presumably
because of descent from common
ancestors, are called ______.
a. analogous structures
b. homologous structures
c. vestigial structures
15 Which of these statements indicates a
problem with the theory of catastrophism?
A) Not all species have been recovered.
B) Many species have become extinct.
C) There are millions of undescribed species
in the world.
D) There are no humans in early fossil
records.
E) The Earth is billions of years old.
16) Structures that serve no apparent
purpose but are homologous to functional
structures in related organisms are called
_______.
a. analogous structures
b. homologous structures
c. vestigial structures
17) The author of On the Origin of Species
by Means of Natural Selection is
A) Mendel.
B) Malthus.
C) Galvani.
D) Darwin.
E) Lamarck
18) . Which of the following lines of evidence
support(s) the idea of evolution ?
a. the fossil record
b. genetic and biochemical analyses
c. comparative anatomy and embryology
d. artificial selection
e. all of the above
19. Which of the following is a mechanism or
cause of evolution?
a. mutation
b. gene flow
c. genetic drift
d. natural selection
e. all of the above
20) The theory of natural selection states
that
A) all individuals live to reproduce in each
generation.
B) only the largest and strongest survive.
C) random assortment of genes results in
better characteristics in the following
generations.
D) the best adapted individuals survive and
reproduce, contributing the most genes to
the next generation.
E) individuals that mutate in response to
their environment will survive.
21. Selection against individuals at both
ends of a phenotypic distribution for a
character, favoring those in the middle or
average of the distribution, is an example of
__________.
a. kin selection
b. sexual selection
c. directional selection
d. disruptive selection
e. stabilizing selection
22. What is a gene pool?
a. a region of DNA found at a specific
position on a chromosome
b. the number of copies of an allele for a
specific gene in a population
c. the total number of all the genes in a
population
d. none of the above
23) Natural selection on a trait can only
occur if the trait is ________.
A) inheritable
B) behavioral
C) favorable
D) morphological
E) a new mutation
24) Which of the following is NOT an
example of natural selection?
A) Plants with thorns are less likely to be
eaten by herbivores than other members of
the same species that lack thorns.
B) Bacterial populations in hospitals develop
resistance to drugs used to combat infection
by them.
C) Scientists breed cows that give greater
amounts of milk than their ancestors.
D) Fruit fly larvae with an enzyme to break
down alcohol are better able to feed on
fermenting fruit than those that lack the
enzyme.
E) Female fish that produce more eggs
leave more offspring than those that
produce fewer eggs.
25. Evolution is best defined as a change in
__________.
a. number of species
b. physical traits
c. DNA sequence
d. allele frequencies
26. Individuals with two identical copies of a
given allele are called
____________________ for that allele.
a. heterozygous
b. twins
c. compatible
d. homozygous
27) Specific inheritable mutations, which
may allow a population to evolve, are :
A) produced by chance.
B) produced as a response to environmental
change.
C) produced as a response to selection
pressure.
D) produced by other species in the
environment.
E) produced by artificial selection.
28) A change in the genetic makeup of a
population is
A) natural selection.
B) uniformitarianism.
C) artificial selection.
D) evolution.
E) genetic drift.
29) Evidence which supports the theory of
evolution is found in the studies of
A) embryos.
B) biochemistry.
C) fossils.
D) artificial selection.
E) all of these
30) The fossil record indicates that over the
last 50 million years the horse has evolved
in all but which of the following ways?
A) tooth structure
B) leg anatomy
C) overall size
D) abundance of hair
E) It has evolved in all these respects.
31) Structures which are homologous to
important structures in other organisms but
serve no purpose in the organism being
considered are
A) analogous.
B) mutations.
C) homozygous.
D) convergent.
E) vestigial
32) Which of the following structures is NOT
homologous to the others?
A) alligator forelimb
B) bird wing
C) human arm
D) insect wing
E) bat wing
33) Strong evidence for the close
relatedness of vertebrates is
A) they all have legs.
B) their means of reproduction.
C) the similarity of their embryological
stages.
D) they all evolved from fish.
E) they all possess DNA.
34) The many different breeds of domestic
dog were produced by
A) natural selection.
B) artificial selection.
C) kin selection
D) mutation.
E) divergent evolution.
35) Most commercial pesticides are
effective for only 2-3 years. This is because
A) new pests invade the area.
B) the chemicals induce mutations that
convey immunity.
C) the chemicals mutate.
D) the pests learn to ignore the chemicals.
E) those pests with advantageous mutations
will survive and reproduce.
36) Anolis lizards are transplanted from an
area with many large trees to islands with
many small plants and few trees. You would
predict them to
A) undergo no evolutionary change.
B) evolve shorter legs.
C) evolve longer legs.
D) evolve to be able to run away from
predators more quickly.
E) evolve to be able to maneuver less
efficiently.
37) The Hardy-Weinberg equilibrium
represents an idealized, evolution-free
population in which the allele frequencies
and genotype frequencies will not change
over time. In order for this to happen, five
conditions must be met: 1) there must be no
mutation; 2) there must be no gene flow
between populations; 3) the populations
must be very large; 4) all mating must be
random; and 5) there must be no natural
selection. If one of these five conditions was
violated, genetic change, and thus evolution,
would occur in the populations of
subsequent generations. Suppose that only
condition 3 were violated—that the
population was very small. In this situation,
the evolution would probably be due to
_________.
a. mutation
b. migration
c. genetic drift
d. natural selection
e. all of the above
38) Genetic drift, population bottlenecks,
and founder populations all illustrate
__________.
a. decreasing population size has a greater
effect on changing allele frequencies than
increasing the population size
b. that reducing population size will likely
decrease genetic variability within the
population
c. the strong role played by very small
isolated populations in the creation of new
species
d. all of the above
39) What type of natural selection favors
individuals with rarely encountered traits
over individuals with traits that are frequently
encountered?
a. disruptive selection
b. stabilizing selection
c. directional selection
40) Gene flow __________.
a. cannot influence the evolution of a
population
b. prevents the spread of alleles through a
species
c. causes populations to diverge from each
other
d. makes populations more genetically
similar
41) Why is the sickle cell allele found at a
high frequency in African human
populations?
a. Individuals with sickle cell anemia are
resistant to malaria, which has historically
been prevalent in Africa.
b. Heterozygote carriers of the allele are
susceptible to malaria, which has historically
been absent in Africa.
c. Individuals with sickle cell anemia are
susceptible to malaria, which has historically
been absent in Africa.
d. Heterozygote carriers of the allele are
resistant to malaria, which has historically
been prevalent in Africa.
42) Before the modern era of science,
organisms were assigned to species
categories on the basis of
A) behavioral similarities.
B) existence of fossils of previous forms.
C) capability of interbreeding.
D) similarities in appearance.
E) geographic location.
43) What is: "all the populations of
organisms that can potentially interbreed
with one another under natural
circumstances and are reproductively
isolated from other populations"?
A) genus
B) species
C) genotype
D) community
E) tribe
44) Fruit fly species all look more or less
alike. If you have a male and female fruit fly
how can you prove that they are the same
species?
A) Determine the base sequence of the DNA
of their chromosomes.
B) Examine them closely with a low power
microscope comparing their physical
characteristics to published species key lists
of characteristics.
C) If they mate when they are put together
then they are the same species.
D) If they mate successfully and their
offspring can also mate successfully all are
the same species.
E) If they can both asexually reproduce and
their offspring can also successfully
asexually reproduce then they are all the
same species.
B) behavioral isolation.
C) mechanical isolation.
D) hybrid inviability.
E) allopatric speciation.
48) The Kaibab squirrel lives on the north
side of the Grand Canyon and the Abert
squirrel lives on the south side. Even though
these two populations are only miles apart,
their gene pools are kept isolated by
A) mechanical incompatibility.
B) hybrid infertility
C) geographic isolation
D) ecological isolation.
E) temporal isolation.
49) The flies that show a preference for
either hawthorn or apple trees, and are no
longer interbreeding populations because of
this, illustrate what type of speciation?
A) allopatric
B) specialization
C) polyploidy
D) founder effect
E) sympatric
45) Populations once considered to be
separate species are now sometimes
assigned to the same species because
A) it was discovered that they can produce
viable and fertile hybrid offspring.
B) they have evolved to look different.
C) they are no longer capable of
interbreeding.
D) they have evolved to look the same.
E) they have been found to be genetically
similar.
50) All members of the golden hamster
species known today are descendants of a
single litter collected in Syria in 1939. Its
diploid chromosome number is 44. Two
other species of hamster, each with a diploid
number of 22 overlap in Syria. The golden
hamster is thought to be a new species
following the mating of a male and female of
the two other hamster species. What
mechanism might explain this recent event
of speciation?
A) adaptive radiation
B) formation of fertile hybrid and halving of
the chromosome number of this hybrid
C) polyploidy
D) temporal isolation
E) disruptive selection
46) If there is no gene flow into a
population, it is said to be
A) allopatric.
B) sympatric.
C) a founder population.
D) isolated.
E) in a bottleneck.
51) The organisms most likely to undergo
sympatric speciation by polyploidy are
A) mammals.
B) insects.
C) plants.
D) protists.
E) birds.
47) Two species of squirrels live on either
side of the Grand Canyon. They are an
example of
A) temporal isolation.
52) When a species invades a new habitat
and evolves rapidly into several new species
to better exploit new resources what has
occurred?
A) phyletic speciation
B) divergent speciation
C) stabilizing selection
D) polyploidy
E) adaptive radiation
53) Two different species of pine release
their pollen at different times. This is an
example of
A) geographical isolation.
B) ecological isolation.
C) behavioral incompatibility.
D) temporal isolation.
E) mechanical isolation.
54) Blue-footed boobies of the Galapagos
will only mate after a very specific courtship
display on the part of the male. He high
steps to advertise his bright blue feet. What
isolating mechanism discourages mating
outside the species?
A) ecological isolation
B) temporal isolation
C) behavioral isolation
D) mechanical isolation
E) gametic incompatibility
55) In many species of fireflies males flash
to attract females. Each species has a
different flashing pattern. This is an example
of
A) allopatric speciation.
B) geographical isolation.
C) temporal isolation.
D) natural selection.
E) behavioral isolation.
56) One method of protecting the genetic
identity of a population is the inability of
sperm to fertilize eggs of a different species.
This is called
A) ecological isolation.
B) temporal isolation.
C) behavioral isolation.
D) hybrid inviability.
E) gametic incompatibility.
57) The great dane and the chihuahua are
both domestic dogs (the same species), but
mating between them is limited by
A) hybrid infertility.
B) hybrid inviability.
C) mechanical incompatibility.
D) behavioral isolation.
E) heterozygote disadvantage.
58) A horse has 2N=64 and a donkey has
2N=62. The hybrid of these two species,
mules have 63 chromosomes and are
sterile. Why are mules sterile?
A) They cannot physically mate with each
other.
B) They cannot physically mate with horses
and donkeys.
C) Some chromosomes lack homologs and
cannot undergo meiosis.
D) Their zygotes cannot complete the first
mitotic division to form the two cell stage.
E) Only autoploid interspecies hybrids are
able to form new species.
59) If a hybrid is unable to produce sperm
because meiosis does not proceed correctly,
gene flow between the populations is
restricted by
A) hybrid viability.
B) hybrid infertility.
C) gametic isolation.
D) ecological isolation.
E) temporal isolation.
60) The greatest cause of extinctions is
A) asteroid impacts.
B) interactions with other species.
C) overspecialization.
D) habitat destruction..
E) limited species range.