Q4_Fall_2016_AlertDiver

While the Earth’s tectonic plates have been in

constant movement, sea levels have risen and fallen

during periods of cooling and warming, forming

and razing barriers to fish and invertebrate dispersal

through the oceans. When sea levels fall, these

intermittent barriers, such as land bridges between

islands, ultimately lead to new species evolving through

what is known as allopatric speciation. This is the

most common means of species creation; it occurs

when a population that is geographically separated and

genetically isolated from its ancestors eventually adapts

to its slightly different environment due to random

beneficial genetic mutations that arise in the course of

sexual reproduction. This process explains how one