Speciation

 

I believe that speed of speciation is heavily dependent on the type of speciation occurring and natural selection. "When selection is intense, rapid speciation is likely to occur". Comparatively, if natural selection is weaker/ less intense it would take longer for the speciation process to completely happen. You also need to include generation time in your factors as animals that can multiply quickly with short and quick generation times will have a shorter speciation process. For example, the female Flea can live for up to 3 months and lay over 2,000 eggs within 50 days at about 50 eggs per day. The speciation process would be shorter in the Flea compared to an Elephant which only produce 1 young on average and live up to 70 years. Still, we have to take the types of speciation into consideration. 

Allopatric speciation is when a population is divided and isolated by a geographical barrier. There is no gene flow happening between the two populations. An example of allopatric speciation is the squirrels in the Grand Canyon. Back when the Grand Canyon was forming, it isolated a squirrel population. It created two species of squirrels; the Kaibab(left) and Abert(right) squirrel 

Parapatric speciation occurs when there is partial spatial isolation. Therefore there is partial gene flow. An example of this is the fish we recently studied in our RStudio assignment. One fish population was found in non-sulfidic waters while the other was found in sulfidic waters. Some individuals were able to go freely between the two waters but individualds on the extreme ends of the spectrum would die crossing over into the other water they're not adapted for. This separates the population rather quickly. But not as quickly as allopatric as there is some gene flow fond in Parapatric speciation. 

Sympatric speciation occurs when populations are inhabiting the same area but are isolated by either sexual selection, genetic polymorphism, or habitat differentiation (if applicable). An example of this would be two populations of fish sharing a lake but one stays near the shore and the other stays at the bottom of the lake. This one is much more rare to find. 

All in all, many factors influence the speciation process. 

References: https://biologydictionary.net/allopatric-speciation/