Question 1

The mutation accumulation and antagonistic pleiotropy hypotheses for senescence both make which of the following predictions about extrinsic mortality?

Accepted Answer

A)  Senescence occurs earlier in populations with higher rates of extrinsic mortality. 
B)  Senescence occurs later in populations with higher rates of extrinsic mortality. 
C)  Extrinsic mortality decreases in response to selection for later senescence. 
D)  Extrinsic mortality rate is not correlated with senescence.

Question 2

All of the following are true of V(D)J recombination EXCEPT it

Accepted Answer

A)  leads to the production of B-cell antibodies and T-cell receptors. 
B)  relies on a random process of somatic recombination. 
C)  can create millions of different receptors by combining a relatively small number of subunits. 
D)  produces receptors that bind to only nonself proteins.

Question 3

The size difference between most multicellular hosts and their pathogens results in which of the following evolutionary advantages for the pathogen?

Accepted Answer

A)  Pathogens have larger population sizes and shorter generation times than hosts, allowing for increased rates of adaptation. 
B)  Pathogens have lower mutation rates than hosts, resulting in more stable populations. 
C)  Hosts evolve more rapidly due to mutations induced by the pathogen. 
D)  Host population sizes increase in the presence of a pathogen, providing more potential hosts for infection.

Question 4

These graphs show how world-record performance in (A) track and (B) field events vary with age. What phenomenon do these data demonstrate?

Accepted Answer

A)  rate of living 
B)  senescence 
C)  age-specific mortality 
D)  natural selection

Question 5

Patients with severe bacterial sepsis who develop a fever have higher survival rates than those who do not develop a fever. Does this observation provide causative evidence for the beneficial role of fever in fighting infections?

Accepted Answer

A)  Yes; patients who develop a fever will have a higher mean fitness. 
B)  Yes; developing a fever is correlated with a strong immune system. 
C)  No; the disease in patients without fever may have been too severe to allow the body to develop a fever. 
D)  No; fever has been shown by other studies to be inconsequential in fighting infections.

Question 6

Does this graph provide evidence in support of the rate-of-living hypothesis for senescence?

Accepted Answer

A)  No; the rate-of-living hypothesis does not make any predictions about the relationship between metabolic rate and life span. 
B)  Yes; these data demonstrate that high metabolic rates cause longer life spans. 
C)  No; the rate-of-living hypothesis predicts that life span should increase with increasing metabolic rate. 
D)  Yes; this graph shows the expected inverse relationship between metabolic rate and life span.

Question 7

Explain why it was beneficial for primitive fish to have a pouch of esophagus or gut tissue that trapped gas bubbles, but why it was problematic for humans.

Accepted Answer

The answer of Explain why it was beneficial for primitive...

Question 8

Which of the following is a mechanism that many pathogens have evolved to subvert the host immune system?

Accepted Answer

A)  down-regulation of various aspects of the innate immune system 
B)  increased rate of evolution in the host 
C)  clonal selection and clonal expansion 
D)  high mutation rate in the adaptive immune system

Question 9

Name Niko Tinbergen's four levels of explanation. Write one question about fever that addresses each level of explanation. Limit your answer to one sentence for each level.

Accepted Answer

The answer of Name Niko Tinbergen's four levels of explanation....

Question 10

Which of the following describes a proximate explanation for fever in mammals?

Accepted Answer

A)  Immune cells recognize the presence of a pathogen and release cytokines, which signal a shift in body temperature. 
B)  Fevers result in better disease outcomes. 
C)  Fevers increase metabolic rate and exacerbate tissue damage. 
D)  Natural selection has tuned the defensive response so fevers are induced even when they may not be needed.

Exam 20: Evolution and Medicine