How can we help?

You can also find more resources in our Help Center.

40 terms

BIO11A - Exam 4

Chapters 22, 23, 24
Natural selection is based on all of the following except:
a) populations tend to produce more individuals than the environment can support
b) genetic variation exists within populations
c) individuals adapt to their environments and, thereby, evolve
d) the best-adapted individuals tend to leave the most offspring
c) individuals adapt to their environments and, thereby, evolve
Swine are vulnerable to infection by bird flu virus and human flu virus, which can both be present in an individual pig at the same time. When this occurs, it is possible for genes from bird flu virus and human flu virus to be combined, thereby producing a genetically distinctive virus, which can subsequently cause widespread disease.
gene flow
Which of the following is most likely to produce an African butterfly species in the wild whose members have one of two strikingly different color patterns?
disruptive selection
In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of allele, a, is 0.1. What is the frequency of individuals with AA genotype?
Two species of snails are physically unable to mate. This is an example of:
mechanical incompatibility
In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of the allele, a, is 0.3. In a population of 100, how many individuals will be homozygous for this allele?
Two species of pines, P. radiate and P. muricota, live in the same regions of California and are capable of forming hybrids under laboratory conditions. However, they do not interbreed because one releases pollen in February and the other in April. What genetic isolating mechanism is involved?
Two species of frogs belonging to the same genus occasionally mate, but the offspring fail to develop and hatch. What is the mechanism for keeping the two frog species separate?
the post zygotic barrier called hybrid inviability
Boa constrictors have tiny pelvic girdles and leg bones inside their bodies. Because these structures are nonfunctional "evolutionary baggage", they are called:
Within six months of effectively using methicillin to treat S. aureus infections in a community, all new infections were caused by MRSA. How can this result best be explained?
Some drug-resistant bacteria were present at the start of treatment, and natural selection increased their frequency.
Rank the following from most general to most specific:
1. gametic isolation
2. reproductive isolating mechanism
3. pollen-stigma incompatibility
4. prezygotic isolating mechanism
2. reproductive isolating mechanism
4. prezygotic isolating mechanism
1. gametic isolation
3. pollen-stigma incompatibility
Imagine a population of monkeys in S. America whose habitat has been reduced to the point where only 20 individuals survive. This is an example of:
a population bottleneck
Two populations of flowers found in the same meadow look identical but are pollinated by different pollinators: one by a night-flying hummingbird moth, and the other by honeybees that fly by day. This is an example of:
temporal isolation
Which of these statements BEST illustrates the theory of catastrophism?
a) Species become extinct due to natural disasters, such as floods and volcanic eruptions.
b) The fossil record is incomplete.
c) There are no humans in early fossil records because they had not been created yet.
d) Only plant species have become extinct.
e) Only extinct species appear in the fossil record.
a) Species become extinct due to natural disasters, such as floods and volcanic eruptions.
During a study session about evolution, one of your fellow students remarks, "The giraffe stretched its neck while reaching for higher leave. Its offspring inherited longer necks as a result." Which statement is most likely to be helpful in correcting this student's misconception?
Characteristics acquired during an organism's life are generally not passed on through genes.
Two species of squirrels live on either side of the Grand Canyon. It is believed that a long time ago, before being separated by the canyon, they were the same species. This is an example of:
allopatric speciation
Which scientist devised the theory of uniformitarianism to account for Earth's old age?
In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of allele, a, is 0.2. In a population of 100, how many individuals will be heterozygous for this allele?
Which of the following is NOT an observation or inference on which natural selection is based?
a) There is heritable variation among individuals.
b) Only a fraction of an individual's offspring may survive.
c) Species produce more offspring than the environment can support.
d) Individuals whose characteristics are best suited to the environment generally leave more offspring than those whose characteristics are less well suited.
e) Poorly adapted individuals never produce offspring.
e) Poorly adapted individuals never produce offspring.
Temporal isolation is an example of:
a prezygotic isolating mechanism
Sexual dimorphism is most often a result of:
intersexual selection
The human upper arm bone (the humerus) is structurally similar to the upper wing bone of a bat. The structural similarity is an example of:
homologous structures.
Most commercial pesticides are effective for only two or more years because:
those pests born with mutations that provide immunity will survive and reproduce
DNA sequences in many human genes are very similar to the sequences of corresponding genes in chimpanzees. The most likely explanation for this result is that:
humans and chimpanzees share a relatively recent common ancestor
If the tallest and shortest individuals of a population of humans do not survive and reproduce, as well as, the individuals of "average" height, which type of selection would most likely result?
stabilizing selection
Imagine that a population of hummingbirds with an intermediate beak size develops longer beaks over time. This is an example of:
directional selection
The process by which allele frequencies are altered in a population due to chance is:
genetic drift
A hybrid zone is properly defined as:
an area where mating occurs between members of two closely related species, producing viable offspring
The male peacock's beautiful tail is really a trade-off between:
sexual selection and natural selection
Natural selection is BEST described as:
working on the existing variation of traits to favor those better suited to the organism's environment
In a certain species of salmon, some adult males are extremely large, whereas, other adult males are very small, compared to females. There are no intermediate-sized adult males in the population. This probably due to:
disruptive selection
Some animal species found in caves have tiny, nonfunctional eyes. These are BEST described as:
vestigial structures
Female blue-footed boobies of the Galapagos Islands will mate only after a very specific courtship display on the part of the male. He high-steps to advertise his bright blue feet. What mechanism discourages female blue-footed boobies from mating with other species of boobies that have different courtship displays?
behavioral isolation
Over time, the movement of people on Earth has steadily increased. This has altered the course of human evolution by increasing:
gene flow
An allele frequency is:
the relative proportion of a given allele in a population
Which statement illustrates Lamarck's theory on the mechanism of evolution?
A man who routinely shaves the hair off his head will have sons who become bald.
Lions and tigers can interbreed and produce offspring called tiglons or ligers, which have normal spans but are sterile. Lions and tigers remain isolated genetically because of:
hybrid infertility
Habitat loss, natural catastrophes, and/or excessive harvesting of a species often result in:
population bottlenecks
Natural selection can act on a certain trait only if the trait is:
Sparrows with average-sized wings survive severe storms better than those with longer or shorter wings, illustrating:
stabilizing selection