Question

Harbor seals live in northern oceans and have a layer of blubber (fat) that keeps them warm. Seals can have blubber of different thicknesses.

Seals with thicker blubber are more likely to stay warm and survive in cold ocean waters. But, in warm ocean waters, thicker blubber can make the seals overheat and die.

The diagrams below show three possible seal populations.

Diagram titled Population 1 containing a row of 6 seal icons labeled Thin Blubber.
Diagram titled Population 2 containing 2 rows of 4 seal icons each, one labeled Thin Blubber and one labeled Thick Blubber.
Diagram titled Population 3 containing a row of 6 seal icons labeled Thick Blubber.
6. If their environment changes to have warm water, which of the following seal populations will most likely survive?
Responses

a
Populations 1 and 2 will most likely survive.
Populations 1 and 2 will most likely survive.

b
Populations 2 and 3 will most likely survive.
Populations 2 and 3 will most likely survive.

c
Only Population 2 will survive because it is the only population with variation.
Only Population 2 will survive because it is the only population with variation.

d
All the populations will survive because the seals will change the thickness of their blubber if they need to.

Answer 1

The correct response is:

**c** - Only Population 2 will survive because it is the only population with variation.

In warm water, seals with thick blubber would struggle due to overheating, while seals with thin blubber would be better suited to the warmer environment. Population 1 has only thin blubber seals, and Population 3 has only thick blubber seals. Only Population 2 has both thin and thick blubber seals, allowing for some individuals to thrive in the warmer conditions.