Question 1

The great diversity of life on Earth is caused by the formation of new species in a process known as ________.

Accepted Answer

speciation

Question 2

Adaptive evolution

Accepted Answer

A)  is large-scale movement of a single species over a new geographic area.
B)  occurs when a more adapted species causes the extinction of a less adapted one.
C)  is the process by which natural selection improves the match between an organism and its environment over time.
D)  is an increase in the adaptiveness of many species that have already evolved. C

Question 3

Choose two different reproductive barriers that lead to sympatric speciation and explain how they work.

Accepted Answer

Sympatric speciation occurs when new species form in the same geographic location. Ecological, behavioral, and mechanical isolation all prevent mating from occurring. Gametic isolation prevents fertilization after mating has occurred. There are also two postzygotic barriers-zygote death and hybrid performance-that act as barriers after fertilization has occurred.

Question 4

This figure shows two squirrels that represent two separate species. Explain how the geographic barrier between these two populations led to the formation of two distinct species.

Accepted Answer

The answer of This figure shows two squirrels that represent...

Question 5

A large population of animals is split in two by a physical barrier. Over time, the genetic makeup of the two resulting populations becomes more and more different until each population becomes a separate species. This is an example of

Accepted Answer

A)  sympatric speciation.
B)  allopatric speciation.
C)  genetic drift.
D)  natural selection.

Question 6

Speciation

Accepted Answer

A)  can result from geographic isolation.
B)  occurs in the absence of genetic divergence.
C)  occurs only in species living on remote islands.
D)  reduces variation.

Question 7

Two species live near each other but do not respond to each other's courtship displays. This is an example of ________ isolation, a type of prezygotic barrier.

Accepted Answer

The answer of Two species live near each other but...

Question 8

Which of the following correctly indicates a relationship between the morphological species concept and the biological species concept?

Accepted Answer

A)  Organisms that reproduce asexually cannot be defined as a species based on morphology.
B)  Organisms capable of interbreeding always have the same physical traits.
C)  Organisms capable of interbreeding might have different physical traits.
D)  The morphological and biological species concepts are always in agreement.

Question 9

How does geographic isolation lead to speciation?

Accepted Answer

A)  Geographic isolation allows mechanisms of evolution to cause genetic divergence.
B)  Populations that are geographically isolated develop reproductive barriers.
C)  The habitats for geographically isolated species are always different and this leads to morphological differences.
D)  Geographic isolation does not lead to speciation.

Question 10

For which of the following would a mountain range most likely represent a geographic barrier that would block gene flow?

Accepted Answer

A)  birds
B)  deer
C)  mice
D)  butterflies

Question 11

Close ecological interactions between two different species may lead to

Accepted Answer

A)  allopatric speciation.
B)  sympatric speciation.
C)  coevolution.
D)  geographic isolation.

Question 12

Two species evolving together in response to interactions between the two species is referred to as ________.

Accepted Answer

The answer of Two species evolving together in response to...

Question 13

Which of the following does NOT provide an example of geographic isolation?

Accepted Answer

A)  Two populations live in two valleys on opposite sides of a mountain range.
B)  Two populations live on different mountains with a valley between them.
C)  Two populations live on opposite sides of a river.
D)  Two populations live in different parts of a small lake.

Question 14

Sympatric speciation

Accepted Answer

A)  occurs only in plants.
B)  is impossible, because the populations of a species must be isolated from one another for speciation to occur.
C)  is always a result of polyploidy.
D)  occurs when a new species emerges from a population in the absence of a geographical barrier.

Question 15

Which of the following statements gives an example of coevolution?

Accepted Answer

A)  Two unrelated species form at the same time after ancestral species populate a newly formed volcanic island.
B)  Two closely related mice species on different mountaintops in the southwest United States both adapt the same trait because food sources are similar.
C)  An ant species and a plant species both develop adaptations in response to changes in the other species.
D)  A wild cat species and a wild dog species both have similar bacteria living in their guts, which allow them to produce vitamin K.

Question 16

The two squirrel species shown in the figure arose from the same ancestor. The Kaibab squirrel lives on the north rim of the Grand Canyon and Abert's squirrel lives on the south rim. Which is the most likely explanation for their speciation?

Accepted Answer

A)  The population of ancestral squirrel occupied only one of the rims of the Grand Canyon. As the population grew, some members of the population crossed the Grand Canyon to form a new population.
B)  The population of the ancestral squirrel was split by the formation of the Grand Canyon. Since the habitats were different on each rim, the populations evolved differently and became reproductively isolated.
C)  When the Grand Canyon formed, competition for food and shelter became fierce. The two species arose through sympatric speciation as some individuals gathered food on the north rim rather than on the south rim.
D)  The ancestral squirrel was actually a hybrid of two squirrel species. When the populations were separated and could no longer mate, the characteristics of the two species became more obvious.

Question 17

Some freshwater snail eggs are accidentally introduced into a new habitat that is geographically isolated from the original population. Which of the following must occur before these snails are described as two separate species?

Accepted Answer

A)  gene flow
B)  sympatric speciation
C)  adaptation
D)  genetic divergence

Question 18

Adaptive evolution allows species to

Accepted Answer

A)  reduce mutation rate.
B)  decrease genetic variation.
C)  adjust to environmental changes.
D)  hybridize.

Question 19

If two populations of beetles living in isolated areas are physically different but genetically similar, would they be considered one species or two? Explain your answer.

Accepted Answer

The answer of If two populations of beetles living in...

Question 20

Some species of orchids attract wasps to assist them in reproduction by producing flowers that look like female wasps. The flowers fool male wasps into attempting to mate with them. As a result, the wasp is covered with pollen that it takes with it to the next flower it attempts to mate with. This example shows adaptive evolution by

Accepted Answer

A)  the orchids.
B)  the wasps.
C)  all flowering plants.
D)  ancestral wasps.

Exam 12: Adaptation and Species