Deck 15: Extinction and Evolutionary Trends

Question 1

Which of the following observations would be expected if an infectious disease were a contributor to amphibian decline?

A)Amphibian decline occurs simultaneously at many points throughout the entire range of amphibian populations.
B)Amphibian decline correlates with habitat alteration.
C)When transplanted into declining populations, individuals from nondeclining populations show the same symptoms as in-decline individuals.
D)Symptoms of in-decline individuals can be cured by medication.
E)C and D

Answer 1

E

Question 2

Elevated levels of iridium are found in the geologic layer at the K-T boundary.Is this unusual?

A)Yes. Iridium is a common metal on Earth but rarely accumulates in a singe layer.
B)No. Iridium is a rare element on Earth, but geological layers of iridium are not uncommon.
C)Yes. Iridium is a rare metal on Earth.
D)Yes. Composition differences between geological layers tend to equilibrate over time.

Answer 2

C

Question 3

Native plant A is endangered.You suspect that part of the reason for its decline is competition with an introduced exotic plant,B,that occupies a similar ecological niche.Which of the following experiments would help you decide whether competition with B contributes to the decline of A?

A)Raise each species by itself in the absence of competition in a greenhouse, and measure growth and reproductive rates.
B)Establish experimental plots in which you remove plant B.
C)Count the number of seeds produced by A and B in nature.
D)Quantify damage by herbivores on A and B in nature.
E)All of the above

Answer 3

E

Question 4

While studying a group of ammonites (an extinct lineage of cephalopods)that lived during the Mesozoic,you measure the shell diameter of different fossil ammonite species.The table below represents the data you collected for each of six different time periods.What rule does the data conform to?

A)Biogenetic rule
C)Cope's rule
B)Allen's rule
D)Bergmann's rule

Question 5

What is a sink population?

A)A large panmictic population comprising all members of a species
B)A metapopulation
C)A local population that would likely decline to extinction without immigration
D)A local population in which emigration rate exceeds immigration rate
E)A and B

Question 6

Where would you place the actual extinction date of a taxon if you knew that the Signor-Lipps effect was at work?

A)Exactly at the date of the last known fossil
B)Before the date of the last known fossil
C)After the date of the last known fossil
D)It is not possible to determine when extinction occurred relative to the date of the last known fossil.

Question 7

The graph below shows extinction rates during different periods of Earth's history.How many mass extinction events do scientists commonly infer from these data?

A)Two
C)Five
B)Thirteen
D)Three

Question 8

The figure below shows the increasing morphological complexity in crustacean legs in 12 different phylogenetic comparisons.Why did the authors of this study choose to analyze the data independently for each comparison?

A)The lower sample size in each comparison makes for a more powerful statistical test.
B)This methods allows testing for species selection within each of the 12 comparisons.
C)The observed pattern allows the exclusion of species selection as a possible evolutionary mechanism.
D)This method controls for phylogenetic correlations.

Question 9

Extinction of a species means that

A)all members of the species have died out and have left no descendents.
B)researchers are unable to find individuals of the species in nature.
C)members of the species are not reproducing.
D)the species has died out in part of its geographic range.

Question 10

Which of the following conditions favor(s)fossilization?

A)A dead organism remains exposed for a long time.
B)A dead organism is covered by soft sediment.
C)A dead organism is covered by water.
D)A dead organism is exposed to scavengers that clean the bones.
E)C and D

Question 11

The probability of extinction via predation is particularly high when

A)predator and prey have coevolved over long periods of time.
B)prey populations are stressed by additional environmental factors.
C)predators are a new arrival to the prey's habitat.
D)the prey species is long lived and has a low birthrate.
E)B, C, and D

Question 12

The earliest Homo sapiens fossils are about 200,000 years old.Could you use radiocarbon dating to determine the age of fossils from that period? Briefly justify your answer.

Question 13

What is the hallmark trait of aquatic organisms that survived the Permian extinction?

A)They lived in shallow seas.
B)They were exceptionally small.
C)None of them inhabited reefs.
D)They were able to withstand anoxic conditions.
E)All of the above

Question 14

Why are endemic species particularly endangered by global climate change?

A)Endemic species occur predominantly in colder regions.
B)All endemic species have long generation times that make evolutionary adaptation to climate change prohibitively slow.
C)All endemic species are already stressed by other human impact.
D)Small and isolated geographic ranges make avoiding unfavorable climate conditions difficult.
E)C and D

Question 15

Data on extinction rates pre- and post-mass extinction rates suggest that the extinction rate remains elevated for some time after the mass extinction event.Which of the following statements is a plausible explanation for this observation?

A)The negative effects of the original cause for the mass extinction persist after the original event.
B)Although not completely extinct, many surviving species are confined to small geographic ranges that make them vulnerable to local extinction events.
C)High mortality led to the loss of genetic diversity in survivors.
D)Adaptive radiations after mass extinctions produce new predators and competitors that led to the extinction of mass extinction survivors.
E)All of the above

Question 16

The graph below shows the extinction rates for families of marine organisms over different periods of Earth's history.What is the best estimate for the background extinction rate given these data?

A)14-20 families per million years
C)2-5 families per million years
B)8-12 families per million years
D)2-20 families per million years

Question 17

Which mass extinction led to the disappearance of the dinosaurs?

A)K-T mass extinction
C)Triassic mass extinction
B)Permian mass extinction
D)Devonian mass extinction

Question 18

Approximately what percentage of marine species was lost during the Permian extinction?

A)40%-50%
C)70%-80%
B)50%-60%
D)80%-90%

Question 19

Which of the following is the greatest known mass extinction to date?

A)K-T mass extinction
C)Triassic mass extinction
B)Permian mass extinction
D)Devonian mass extinction

Question 20

What kinds of evolutionary trends are represented by each of the two diagrams below? The x-axis represents an arbitrary scale for a trait value,in this case eyespot diameter on a butterfly's wing.

A)A = active trend; B = passive trend
C)A = passive trend; B = active trend
B)A and B = active trend
D)A and B = passive trend

Question 21

You are a paleontologist studying the fossil marine fauna immediately after the K-T mass extinction.You find ammonite fossils in the post-K-T layer even though ammonites are believed to have vanished in the K-T extinction.You submit your sensational findings to a journal,but one of the reviewers questions your claim of ammonite survival.He points to the fact that your ammonite fossil was found in rock that shows extensive burrowing activity by benthic organisms.Why does the reviewer question your conclusion?

Question 22

Describe how mean and variance of a trait value change in the absence of an evolutionary trend as a lineage diversifies.Use +,-,or = to indicate an increase,a decrease,or no change,respectively.You can use one,two,or all of the symbols to describe the possible changes in both mean and variance.Mean:
Variance:

Question 23

Explain how the figure below suggests that extinction probability is independent of a taxon's age.Keep in mind that the y-axis is measured on a logarithmic scale.

Question 24

What effect of mass extinctions is described by the expression "dead clade walking"?

Question 25

Which of the following scenarios may produce an active trend in evolutionary change? Briefly justify your answer.
A.The mechanic stability of the exoskeleton of a group of terrestrial arthropods imposes an upper limit on the body size of these organisms.B.The evolution of an endoparasitic lifestyle results in overall smaller body size as parasite species diversify to utilize small-bodied hosts,which are more common than large bodied hosts.