Deck 14: Evolution and Human Health

Question 1

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

A) receptor sites
B) binding sites
C) antibody sites
D) antigenic sites
E) None of the above.

Answer 1

D

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 ________.

A) bacteria generate mutations so that they can evolve in order to become better adapted to their environment
B) the use of antibiotics generates mutations in bacteria that affects their resistance
C) antibiotics really have no effect on bacterial resistance; such fluctuations are natural and occur whether we use antibiotics or not
D) bacterial populations evolve in response to the selection pressure imposed by antibiotics

Answer 2

D

Question 3

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

A) human populations have accumulated a number of mutations that have become fixed by genetic drift
B) the changes in human lifestyle account for all of the increase in frequencies of these conditions
C) these conditions are indeed "diseases of civilization" and are likely caused by the interaction between genes (genetic susceptibility) and novel environments
D) these human conditions are mere artifacts of the way in which they have been evaluated

Answer 3

C

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 ________.

A) supported the hypothesis that fevers are a manipulation of the host by the pathogen
B) supported the hypothesis that fevers are an adaptive response to the pathogen
C) supported both of these hypotheses, but in different contexts
D) were inconclusive

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 ________.

A) H3 was acquired from a nonhuman strain which, in turn, allowed the virus to infect humans on a global scale
B) flu strains, when present together in the same host cell, can trade genes
C) the 1968 human flu strain acquired its H3 gen from a bird virus
D) All of these conclusions are supported by this data.

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 ________.

A) the coincidental evolution hypothesis
B) the shortsighted evolution hypothesis
C) the trade-off hypothesis
D) the energy-balance hypothesis

Question 7

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

A) in populations of bacteria within individual patients
B) in studies comparing newly diagnosed patients v. patients who have relapsed after antibiotic treatment
C) in studies comparing the fraction of patients with resistant bacteria and society-wide use of antibiotics
D) in all of the above examples
E) in no empirical studies; there is no evidence that antibiotics act as a selective agent

Question 8

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

Question 9

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

A) we cannot expect evolution by natural selection in human populations to have kept pace with our changing way of life
B) humans still retain many, if not most, of the features that made us well adapted to living in the hunter-gatherer societies of the stone age
C) we can use knowledge of the differences between our current lifestyle and the lifestyle of our pre-agricultural lifestyle to better understand both the peculiarities of humans and risks associated with our modern lifestyle
D) humans are unique in that we have the capacity evolve by natural selection much more rapidly in response to changes in our environment than other organisms do

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 ________.

A) all of the cells of the population are genetically identical, since they are derived by mitosis from the zygote
B) mutations can occur, but only in cells that develop into tumors
C) mutations could occur in any cell, and if so, they may be still be capable of division, leading to cells with heritable genetic variation
D) 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
E) Both C and D are possible outcomes.

Question 11

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

A) influenza A actually has DNA as its genetic material
B) selection is causing influenza A to become more virulent over time
C) selection by the immune system drives change in hemagglutinin's antigenic sites
D) protein evolution in influenza A is consistent with the neutral theory
E) flu strains from one host cannot exchange genetic material with strains from another

Question 12

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

A) the virus causing these outbreaks were derived from a single strain within which significant mutations changed the protein hemagglutinin
B) these viruses switched from using RNA to using DNA
C) the virus ultimately arose in birds, jumped to pigs, and then was able to switch to humans
D) strong selection produces particularly virulent flu strains with predictable periodicity

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 ________.

A) compensatory evolution by way of mutation events in other genes may very well make antibiotic resistant strains as fit, or even more fit, than sensitive strains
B) an energy balance trade-off outweighs the advantages that antibiotic sensitive strains have otherwise
C) strains sensitive to antibiotics will readily and spontaneously mutate at will to achieve antibiotic resistance, even in the absence of antibiotics
D) None of the above.

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.

Question 15

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

A) one disentangles the effects of culture from evolutionary history in detailed, controlled studies of a single culture
B) groups of humans are separated into control and treatment groups for extensive experimentation
C) data is collected cross-culturally to eliminate the effects of culture on behavior
D) We cannot study human behavior in an evolutionary context.

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?

A) breast cancer
B) myopia
C) obesity
D) lactose intolerance
E) None of these.

Question 17

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

A) To avoid contracting food-borne bacteria, consumers should wash fruits and vegetables and avoid raw eggs and undercooked meat.
B) Consumers should always use antibacterial soaps and cleaners, even when no perceived bacterial threat is present.
C) Patients should not request antibiotics for viral infections, such as colds or flu.
D) When they take antibiotics, patients should complete the course of treatment.
E) To avoid spreading infections from patient to patient, physicians should wash their hands thoroughly between patients.

Question 18

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

A) the coincidental evolution hypothesis
B) the shortsighted evolution hypothesis
C) the trade-off hypothesis
D) the energy-balance hypothesis

Question 19

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

Question 20

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

A) flu virus populations evolve rapidly
B) flu vaccines can take months to prepare
C) researchers must successfully predict which flu strain(s) will survive from among the existing strains to become the next season's epidemic
D) All of these are serious issues.
E) Generalized vaccines are easy to produce; none of these are serious issues.

Question 21

Your text discusses one of the most well-known examples in which human populations have evolved in response to selection imposed by changes in lifestyle.Specifically,this example has to do with a change toward the life-long production of an enzyme that allows humans to digest something our ancestors normally would have ingested only as infants.What is the name of this enzyme?

Question 22

Strokes,cancer,and heart disease are sometimes called ________ [three words] because they are/were rare in hunter-gatherer populations.

Question 23

The relation between the variation in a phenotypic trait and the variation in an environmental variable―in other words,the pattern of phenotypic plasticity in a trait―is called a ________.[two words]

Question 24

The 2011 medical thriller film Contagion revolves around a fictional virus called MEV-1,which causes flu-like symptoms followed by seizures and encephalitis; about 25% of infected patients die.MEV-1 appeared as a result of accidental genetic exchange between a bat virus and a pig virus.Discuss the plausibility of this scenario in the light of recent work on viruses and their evolution.

Question 25

The frequency of antibiotic-resistant bacteria tends to go down when the bacterial population is no longer being exposed to the antibiotic.This implies that bacterial antibiotic resistance mechanisms have a significant ________ to the bacterial population.

Question 26

The idea that fundamental aspects of human behavior are "hardwired" or "programmed" by human genes is sometimes called ________.[two words]

Question 27

Your text discusses Paul Ewald's studies of how evolutionary trade-offs might have influenced the evolution of virulence in human pathogens.One thing your text did not mention is disease caused by food-borne pathogens such as Salmonella,Campylobacter,and Escherichia coli O157:H7.In industrialized nations,fresh food is often shipped in bulk quantities for thousands of miles from where it is grown.This means that food-borne outbreaks can sicken large numbers of people,and also may force the costly recall of large amounts of contaminated food,over wide regions.This is a relatively recent development; for almost all of human history,fresh food had to be eaten close to where it was produced.Apply Ewald's ideas to food-borne diseases.Can we make any predictions of future trends in virulence? Are there steps we can take,specifically based on evolutionary biology,to decrease the incidence and severity of food-borne disease?

Question 28

An insect or other organism that transmits disease from one host to another is called a ________.

Question 29

The ________ [two words] hypothesis for the evolution of virulence states that pathogens may evolve traits that enhance their chances of survival within a host,but that decrease their chances of being spread to a new host.

Question 30

In most vertebrates,full siblings share as many genes with each other,on average,as each one does with either parent.One might predict that serious conflict between siblings should be rare and altruistic behavior should be the norm,given that siblings share the same "genetic interests." As anyone who has ever had a brother or sister knows,this is not always the case.In fact,in a number of bird species,notably eagles and other raptors (birds of prey),females usually lay two eggs; soon after hatching,the larger chick pushes the other chick out of the nest,or otherwise attacks it and tries to kill it.(This behavior is known as Cainism,after the Bible story of Cain and Abel.)Generate a hypothesis to explain this behavior in evolutionary terms.Can you apply this hypothesis to human behavior?