The Geologic time scale makes it easier to see the age of rock layers
Answer:
Parapatric speciation
Explanation:
There are different types of speciation. Parapatric speciation consists of new species evolving from a continuous distribution. That is, there is no physical barrier that might impede the gene flow, in fact, it might continue during the speciation process.
There is an environmental gradient that determines different phenotypes for different environmental conditions. One phenotype is more adapted to one of the distribution extremes than the other phenotype. In the exposed case, the environmental gradient is given by the differences in pH.
In the border between the environmental extremes, there is the primary hybrid zone, where both phenotypic forms might meet and hybridize.
The variety of traits a species has best defines genetic diversity.
