Deck 8: Evolution and Natural Selection

Question 1

Which one of the following statements best describes the difference between artificial and natural selection?

A) Natural selection is limited to physical traits and artificial selection is not.
B) Artificial selection has produced many of the most delicious food items for humans; natural selection has not.
C) Natural selection acts without the input of humans; artificial selection requires human input.
D) Charles Darwin understood natural selection but, at that time, was unaware of artificial selection.
E) Natural selection works on all species; artificial selection works only on laboratory-raised species.

Answer 1

Humans have been forcing evolution for tens of thousands of years by intentionally breeding livestock and plants to suit our needs. This is known as artificial selection. We select for the traits we want and selectively breed organisms with those traits to amplify the frequency of the trait. Charles Darwin proposed a similar mechanism, which he called natural selection, to describe how evolution works. Natural selection is when one organism has an adaptive trait which gives it an advantage over the other individuals. This organism has a better chance of living longer and producing more offspring, which amplifies and passes on the adaptive trait.
The correct Answerto this question is c) Natural selection acts without the input of humans; artificial selection requires human input. The major underlying difference between natural and artificial selection is that humans do the selecting in artificial selection and nature does the selecting in natural selection by giving the organism with an adaptive trait an advantage over the other members in its population.
The same traits can be selected for in both natural and artificial selection. In many cases, humans take a trait that is already prevalent in a species due to natural selection and build on it using artificial selection. The Answerto a) is incorrect.
Both artificial and natural selection has produced good food crops. The Answerto b) is incorrect.
Artificial selection had been around for thousands of years before Darwin was born, so he would have been aware of it. The Answerto d) is incorrect.
Both artificial and natural selection can be used on the same species. The Answerto e) is incorrect.

Question 2

What can be concluded about comparing differences in molecular biology between different species?

A) Extremely different species are fundamentally unrelated in any way.
B) Only DNA sequences can be used to compare relatedness between species.
C) Birds are more closely related to humans than dogs are.
D) Genetic similarities and differences demonstrate species relatedness.
E) The longer two species have been evolving on their own, the fewer the genetic differences between them.

Answer 2

Since Darwin first proposed his theory of evolution by natural selection, there have been ongoing studies done that support his theory and fill in some of the gaps in his understanding. One of these is the information provided from the study of molecular biology. This is when the deoxyribonucleic acid (DNA) of organisms are compared to determine what the differences and similarities are. Individuals within a species will share more similar DNA that individuals from different species. The more unrelated species are, the more their DNA is dissimilar.
The correct Answerto this question is d) Genetic similarities and differences demonstrate species relatedness.
Extremely different species, such as humans and whales, do have some similar DNA since we evolved from the same ancestor. The Answerto a) is incorrect.
Both DNA and amino acid sequences can be used to determine species relatedness. The Answerto b) is incorrect.
Dogs are actually more closely related to humans than birds. The Answerto c) is incorrect.
The number of differences between two species increases the longer these species have been evolving. The Answerto e) is incorrect.

Question 3

Define the following Term:
adaptation

Answer 3

The process by which, as a result of natural selection, a population's organisms become better matched to their environment; also, a specific feature, such as the quills of a porcupine, that makes an organism more fit.

Question 4

Which of the following statements about Charles Darwin is incorrect?

A) He spent five years traveling the world, observing living organisms and collecting fossils.
B) He was under constant pressure from his father to make something of himself.
C) He dropped out of medical school.
D) He was enthusiastic about unleashing his theory of natural selection on the world as soon as he thought of it.
E) He and Alfred Russel Wallace independently came up with the theory of evolution by natural selection.

Question 5

Evolution:

A) occurs too slowly to be observed in nature.
B) can occur in the wild but not in the laboratory.
C) is responsible for the increased occurrence of antibiotic-resistant bacteria.
D) does not occur in human-occupied habitats.
E) None of these statements is correct. Short-Answer Questions

Question 6

Define the following Term:
biogeography

Question 7

Evolution occurs:

A) only when the environment is changing.
B) only through natural selection.
C) almost entirely because of directional selection.
D) only via natural selection, genetic drift, migration, or mutation.
E) by altering physical traits but not behavioral traits.

Question 8

Distinguish between evolution and natural selection. (Restrict your answer to 30 words or fewer.)

Question 9

Define the following Term:
bottleneck effect

Question 10

Which of the following statements about mutations is incorrect?

A) Mutations are almost always random with respect to the needs of the organism.
B) A mutation is any change in an organism's DNA.
C) Most mutations are harmful or neutral to the organism in which they occur.
D) The origin of genetic variation is mutation.
E) All of these statements are correct.

Question 11

What is genetic drift? Why is it a more potent agent of evolution in small populations than in large populations?

Question 12

Define the following Term:
convergent evolution

Question 13

Genetic drift has the strongest effects in populations that are:

A) small.
B) large.
C) characterized by extensive gene flow.
D) in Hardy-Weinberg equilibrium.
E) undergoing natural selection.

Question 14

In The Origin of Species, Charles Darwin wrote: "We may look with some confidence to a secure future of great length. And as natural selection works solely by and for the good of each being, all corporeal and mental endowments will tend to progress towards perfection." Describe three reasons why he is wrong.

Question 15

Define the following Term:
fixation

Question 16

When a group of individuals colonizes a new habitat, the event is likely to be an evolutionary event, because:

A) members of a small population have reduced rates of mating.
B) gene flow increases.
C) mutations are more common in novel environments.
D) new environments tend to be inhospitable, reducing survival there.
E) small founding populations are rarely genetically representative of the initial population.

Question 17

How does the increasing frequency of antibiotic-resistant strains of bacteria represent an example of the occurrence of evolution?

Question 18

Define the following Term:
fossil

Question 19

To establish that evolution by natural selection is operating in a population, one must demonstrate variability for a trait, heritability of that trait, differential reproductive success based on that trait, and:

A) increased complexity of the organism.
B) random mating.
C) progress.
D) continuous change in the environment.
E) nothing else.

Question 20

Define the following Term:
differential reproductive success

Question 21

Define the following Term:
founder effect

Question 22

"Survival of the fittest" may be a misleading phrase to describe the process of evolution by natural selection, because:

A) it is impossible to determine the fittest individuals in nature.
B) survival matters less to natural selection than does reproductive success.
C) natural variation in a population is generally too great to be influenced by differential survival.
D) during population bottlenecks, it is the least fit individuals that have the greatest survival.
E) reproductive success on its own does not necessarily guarantee evolution.

Question 23

Define the following Term:
directional selection

Question 24

Define the following Term:
gene flow

Question 25

Evolutionary adaptation:

A) refers both to the process by which populations become better matched to their environment and to the features of an organism that make it more fit than other individuals.
B) cannot occur in environments influenced by humans.
C) is possible only when there is no mutation.
D) is responsible for the fact that porcupines are at an unusually high risk of predation.
E) occurs for physical traits but not behaviors.

Question 26

Define the following Term:
disruptive selection

Question 27

Define the following Term:
genetic drift

Question 28

Adaptations shaped by natural selection:

A) are magnified and enhanced through genetic drift.
B) are unlikely to be present in humans living in industrial societies.
C) may be out of date, having been shaped in the past under conditions that differed from those in the present.
D) represent perfect solutions to the problems posed by nature.
E) are continuously modified so that they are always matched to the environment in which a population lives.

Question 29

Define the following Term:
evolution

Question 30

Define the following Term:
heritability

Question 31

Artificial selection was used on corn to produce a single strain of corn with increased growth rates and greater resistance to a fungus. Although farmers have continued to select for these traits, the productivity of this strain is no longer increasing. This suggests that:

A) the population size has been decreasing.
B) all or most of the natural variation for these traits has been eliminated.
C) gene migration is a major evolutionary agent in corn.
D) long-term disruptive selection may lead to speciation.
E) artificial selection is not as strong as natural selection.

Question 32

Define the following Term:
fitness

Question 33

Define the following Term:
population

Question 34

In a population in which a trait is exposed to stabilizing selection over time:

A) neither the average value nor the variation for the trait changes.
B) both the average value and the variation for the trait increase.
C) the average value increases or decreases, and the variation for the trait decreases.
D) the average value for the trait stays approximately the same, and the variation for the trait decreases.
E) the average value for the trait stays approximately the same, and the variation for the trait increases.

Question 35

Define the following Term:
homologous structure

Question 36

Define the following Term:
radiometric dating

Question 37

Maze-running behavior in rats:

A) is too complex a trait to be influenced by natural selection.
B) is a heritable trait.
C) is not influenced by natural selection, because it does not occur in rats' natural environment.
D) shows no variation.
E) is influenced primarily by mutation in the laboratory.

Question 38

Define the following Term:
inheritance

Question 39

Define the following Term:
sexual selection

Question 40

The average time to death from starvation in a fruit fly is about 20 hours. Selecting for increased starvation resistance in fruit flies:

A) has no effect, because starvation resistance is not a trait that influences fruit fly fitness.
B) has little effect, because ongoing mutation continuously reduces starvation resistance, counteracting any benefits from selection.
C) cannot increase their survival time, because there is no genetic variation for this trait.
D) has no effect, because starvation resistance is too complex a trait, dependent on the effects of too many genes.
E) can produce populations in which the average time to death from starvation is 160 hours.

Question 41

A fossil is defined most broadly as:

A) the preserved pieces of hard parts (e.g., shell or bone) of extinct animals.
B) any preserved remnant or trace of an organism from the past.
C) the preserved bones of vertebrates.
D) a piece of an organism that has turned into rock.
E) the process of preservation of intact animal bodies.

Question 42

Define the following Term:
migration

Question 43

Define the following Term:
stabilizing selection

Question 44

Georges Cuvier's discovery of fossils of Irish elk and giant ground sloths:

A) supports scientific evidence for extinction.
B) was possible because of Buffon's determination that the earth was more than 6,000 years old.
C) was possible only following Darwin's publication of The Origin of Species.
D) was made in deep ocean trenches.
E) suggested that species are immutable.

Question 45

Which of the following statements about marsupial mammals is correct?

A) They fill many niches in Australia that are occupied by placental mammals in other parts of the world.
B) They are less fit than placental mammals.
C) They have become extinct as a result of the greater fitness of placental mammals.
D) They are more closely related to each other than they are to placental mammals.
E) Both a) and d) are correct.

Question 46

Define the following Term:
mutation

Question 47

Define the following Term:
trait

Question 48

While on the voyage of the HMS Beagle, Darwin:

A) wrote The Origin of Species.
B) nurtured his love of studying nature, exploring plant and animal diversity, and collecting fossils.
C) discovered a love for sea travel.
D) studied Malthus's book Essay on the Principle of Population.
E) corresponded extensively with Alfred Russel Wallace about their ideas on evolution.

Question 49

Convergent evolution can occur only when two species:

A) have a recent common ancestor.
B) live in the same geographic area.
C) are separated by a barrier such as a new river.
D) evolve under similar selective forces.
E) are both unpalatable to predators.

Question 50

Define the following Term:
natural selection

Question 51

Define the following Term:
vestigial structure