Question 1

The specific parts of foreign proteins that the immune system recognizes and "remembers" are called ________.

Accepted Answer

Antigenic sites are specific parts of foreign proteins, also known as antigens, that trigger an immune response and are recognized and remembered by the immune system. Receptor sites and binding sites are not typically associated with the immune system, while antibody sites are the parts of antibodies that bind to antigens.

Question 2

In the late 1980s and early 1990s,the percentage of Icelandic children whose bacterial infections were caused by bacteria resistant to penicillin rose at an alarming rate.After public health officials initiated a campaign to reduce the use of penicillin,resistance dropped off.(See the accompanying figure.) 
This observation is consistent with the hypothesis that ________.

Accepted Answer

The observed trend of resistance to penicillin in Icelandic children suggests that bacterial populations are evolving in response to the selection pressure imposed by antibiotics. The reduction in resistance following the campaign to reduce the use of penicillin further supports this hypothesis. Option A is incorrect as it suggests that bacteria generate mutations proactively towards becoming better adapted to their environment, while option B only covers one aspect of the hypothesis (i.e. the impact of antibiotics on mutations). Option C is incorrect as it disregards the observed trend and assumes that bacterial resistance fluctuates naturally.

Question 3

Research on conditions that are relatively new to human populations such as myopia,breast cancer,and obesity support the conclusion that ________.

Accepted Answer

Research suggests that myopia, breast cancer, and obesity have become more prevalent in human populations due to the interaction between genetic susceptibility and novel environments, such as changes in lifestyle and diet. These conditions are often attributed to the "diseases of civilization" and are not merely artifacts of evaluation. Genetic drift (A) may contribute to the accumulation of mutations but is not the primary explanation for the increase in these conditions. Changes in lifestyle may account for some of the increase, but genetics also play a significant role (B).

Question 4

Two evolutionary hypotheses on the function of fever have been suggested: A fever may reflect manipulation of the host by the pathogen,to the pathogen's benefit,or a fever may be an adaptive response by the host to help to control the pathogen itself.Studies on whether the use of fever-reducing drugs were helpful or interfered with the body's ability to fight the pathogen ________.

Accepted Answer

Studies on the use of fever-reducing drugs have not definitively supported either hypothesis, indicating that the research was inconclusive in determining whether fevers primarily benefit the host or the pathogen.

Question 5

Analysis of the phylogeny of flu viruses reveals that the two 1968 strains (see the accompanying figures)both carry neuraminidase N2,but their hemagglutinins are distantly related (H2 and H3).Moreover,before the global pandemic of 1968,human flu viruses had never carried H3.This observation suggests that ________.

Accepted Answer

The answer of Analysis of the phylogeny of flu viruses...

Question 6

The statement "The virulence of many pathogens in humans may not be a target of selection itself,but rather an accidental by-product of selection on other traits" describes ________.

Accepted Answer

The statement describes the coincidental evolution hypothesis, which suggests that the virulence of pathogens in humans may be accidental and not directly selected for, but rather a by-product of selection on other traits.

Question 7

Evidence for the evolution of antibiotic resistance in bacteria has been evaluated ________.

Accepted Answer

The evolution of antibiotic resistance in bacteria has been evaluated in all of the above examples. Populations of bacteria within individual patients can show the evolution of resistance over time, and studying the difference between newly diagnosed patients and those who have relapsed after antibiotic treatment can help to identify the impact of previous antibiotic exposure on resistance evolution. Additionally, comparing the fraction of patients with resistant bacteria and society-wide use of antibiotics can help to identify the broader impact of antibiotic use on resistance evolution.

Question 8

A group of lineages―such as viral strains―that all descend from a common ancestor makes up a ________.

Accepted Answer

The answer of A group of lineages―such as viral strains―that...

Question 9

Given that humans shifted from hunter-gathers to an agriculturally based society within the last 10,000 years does NOT mean that ________.

Accepted Answer

While humans have the capacity for rapid evolution by natural selection, this does not mean that we have necessarily kept pace with our recent transition to an agriculturally based society. Additionally, while it is true that humans retain many features adapted to our hunter-gatherer societies, this does not negate the possibility of evolutionary changes occurring in response to recent environmental shifts. The knowledge gained from understanding the differences between our pre-agricultural and modern lifestyles is still valuable in better understanding human health and physiology.

Question 10

Multicellular organisms such as humans could be thought of as populations of cells,where each member of the population is derived from a single ancestor: the zygote.In such populations,we would expect to see that ________.

Accepted Answer

Mutations can occur in any cell, and if so, they may be still be capable of division, leading to cells with heritable genetic variation. Mutation events that lead to increased cell survival or more rapid reproduction could, in effect, develop into tissues which evolve by natural selection within the organism. Therefore, both C and D are possible outcomes. Option A is incorrect because mutations can occur in cells during replication. Option B is incorrect because mutations can occur in any cell, not just those that develop into tumors.

Question 11

Initial studies of the influenza A virus by Walter Fitch and colleagues showed that ________.

Accepted Answer

Selection by the immune system drives change in hemagglutinin's antigenic sites, allowing the virus to evade the immune response.

Question 12

Analysis of the 1918 and 2009 flu epidemics reveals that the most likely scenario was that ________.

Accepted Answer

Both the 1918 and 2009 flu viruses are believed to have originated in birds, then jumped to pigs, and subsequently adapted to infect humans.

Question 13

Despite some evidence that antibiotic resistance can confer a fitness disadvantage to bacteria in nonantibiotic environments as compared to susceptible strains,research has also documented that ________.

Accepted Answer

While there is some evidence that antibiotic resistance can confer a fitness disadvantage, research has also shown that compensatory evolution through mutation events in other genes can make antibiotic-resistant strains as fit, or even more fit, than sensitive strains.

Question 14

An unusually dangerous strain of flu that infects humans was reported from China in the spring of 2013.The strain is called H7N9.In this coding scheme,H and N refer to ________ and ________ proteins.

Accepted Answer

The answer of An unusually dangerous strain of flu that...

Question 15

Determining the effects of natural selection on human behavior is much more robust if ________.

Accepted Answer

Collecting data across multiple cultures helps to identify patterns and behaviors that are not solely the result of cultural influences, thereby providing a clearer view of the potential evolutionary aspects of human behavior.

Question 16

The modern lifestyle of humans has generated an apparent increase in the frequency of some conditions,as compared to our hunter-gatherer ancestors.Which of the following is NOT one of them?

Accepted Answer

Lactose intolerance is not a condition that has increased due to modern lifestyle; rather, it is a natural condition for most of the world's population. The ability to digest lactose into adulthood is a relatively recent adaptation in some human populations.

Question 17

Which of the following are NOT one of Stuart Levy's guidelines for limiting the development of antibiotic resistance?

Accepted Answer

Stuart Levy does not recommend always using antibacterial soaps and cleaners, as this can contribute to the development of antibiotic resistance. Instead, good hand hygiene with regular soap and water is recommended unless a specific bacterial threat is present.

Question 18

The statement "Natural selection should favor pathogens that strike an optimal balance between the costs and benefits of harming their hosts" describes ________.

Accepted Answer

The statement describes the trade-off hypothesis, which suggests that pathogens evolve to strike a balance between the costs of harming their hosts (e.g., reducing the host's ability to reproduce or survive) and the benefits of spreading and reproducing within the host.

Question 19

The immune system recognizes and reacts to ________,[two words] specific parts of a foreign protein.

Accepted Answer

The answer of The immune system recognizes and reacts to...

Question 20

The biggest issue facing the successful production of influenza vaccines is that ________.

Accepted Answer

All of the options listed are serious issues facing the successful production of influenza vaccines. The flu virus populations are known to evolve rapidly, which can diminish the effectiveness of a particular vaccine. Making flu vaccines can be time-consuming since they need to be prepared months before the flu season. Researchers must try to predict which flu strains are likely to become the next season’s epidemic. These are fundamental issues that can make it difficult to produce effective vaccines against the flu.

Quiz 14: Evolution and Human Health