Question

Rarely, hybridization has occurred between polar bears and grizzlies. The presence of grolars and pizzlies:

a. suggests that polar and grizzly bears are not different species based on the biological species concept.
b. suggests that polar and grizzly bears are not different species because there are no barriers to reproduction.
c. suggests that polar and grizzly bears are different species because neither hybrid is like the parent.
d. suggests that the time since divergence may not be sufficient for complete reproductive isolation to have occurred.
e. suggests that another glaciation event is needed for polar bears to become another species.

Answer 1

The correct answer is d. suggests that the time since divergence may not be sufficient for complete reproductive isolation to have occurred.

Step-by-step explanation:

Polar bears are evolved from brown bear and grizzly bears are subspecies of brown bear so polar bears and brown bears are different species. These two species habitat is different so they are geographically isolated but due to the melting of ice by global warming, their niche started overlapping.

Commonly they do no reproduce with each other because of the reproductive isolation but they can produce viable hybrids called growlers and pizzlies if interspecies reproduction takes place which shows that the time interval since divergence is not enough that can make these two species completely reproductive isolated. So the right answer is d.