Examine the two squirrel populations in the following figure. the populations are separated by a geographic barrier. if after a long period of the time the two species are no longer separated what evidence is needed to determine if speciation has occurred?

Choices:

1. Hybrid offspring of the two population begin to appear.

2. the two populations are not interbreeding freely.

3. polyploidy is creating new species.

4. one species will increase into a population size twice as large as the other species.