Question

can you answer
A population of squirrels lived together in a forest. An event occurred that caused the population to diverge into two different species over a long period of time. Which of the following is most likely the event that occurred?
There was an increase in the predators in the forest.
A natural disaster occurred that separated squirrels.
The winters were unusually cold in the forest.
A disease affected the squirrel population in the forest.

A population of pigs lives on an island together with burrowing termites. Pigs that have the longest snouts tend to survive more frequently than those with shorter snouts. Over time, most of the pig population is made up of individuals that have very long snouts. This is an example of which type of selection?
directional selection
disruptive selection
stabilizing selection
ecosystem selection

A scientist wrote a paper titled “Directional Selection in Action” after observing a population of mice for 15 years. The mice typically preferred to eat berries, although a few would also eat insects. After a drought in year 3, the scientist observed that more mice were eating insects. By year 10, most of the mice in the population ate insects in addition to berries. Which best describes her article?
Her title is accurate because two opposite extremes are favored.
Her title is accurate because one extreme is favored.
She should change her title because she is observing stabilizing selection.
She should change her title because she is observing disruptive selection.

Which process drives Darwin’s theory of evolution?
natural selection
artificial selection
population diversity
ecosystem diversity

Your teacher describes a population of fish that live in a coral reef. Some fish are dark orange (the same color as the coral). Some fish are nearly white. Most of the fish exhibit a color between dark orange and nearly white. Human activity has led to the bleaching of the coral reefs, making them very pale in color. Over time, the population of fish will be affected. Which graph represents the type of selection that you expect to occur?
A graph has trait value on the horizontal axis and population of individuals on the vertical axis. The original population and population after selection have similar curves, but the original population peaks before the population after selection.
A graph has trait value on the horizontal axis and population of individuals on the vertical axis. The population after selection increases, decreases, increases, and then decreases again. The original population increases at the point that the original population drops.
A graph has trait value on the horizontal axis and population of individuals on the vertical axis. The original population peaks at the same time as the population after selection but the population after selection peaks higher and at a more rapid speed.
A graph has trait value on the horizontal axis and proportion of individuals on the vertical axis. The original population and population after selection have similar curves but the original population is slightly higher at all points.

Answer 1

1) A natural disaster occurred that separated squirrels.
- Geographic separation (allopatric isolation) is most likely to lead to divergence into two species.

2) directional selection
- Pigs with longer snouts are favored and the trait distribution shifts toward that one extreme.

3) Her title is accurate because one extreme is favored.
- The population shifted toward insect-eating (one extreme), so this is directional selection.

4) natural selection

5) The first graph (original peak occurs before the after-selection peak) — the graph showing a shift in the population peak (directional selection).