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.