Describe the steps of speciation beginning with geographic isolation?

Answer 1

Two populations are isolated geographically (or mechanically - perhaps there is a mutation that prevents physical copulation, like a change in the direction of the turn of snail shells). One undergoes some selective pressure that the other does not, such as a change in the environment or new predators moving in. The population under stress adapts to the changes, and the genetic mutations involved are extensive enough such that if the two populations do meet again, they can no longer produce viable offspring.

Answer 2

Geographic isolation refers to a situation where a species, or a population of a species, becomes separated by a physical barrier (a lake, ocean, mountains, etc.), allowing each group to diverge along separate evolutionary paths.

The effect of geographic isolation is that the two populations are subjected to different selection pressures, since the conditions in the two areas will be different. So different alleles will be selected for, and genetic differences will gradually accumulate between, the populations.

In time, enough genetic differences will occur so that the two populations will no longer interbreed. Then, by definition, they have become different species.

Answer 3

geographic barrier/geographic barrier - genetic divergence - reproductive isolation -speciation