Final answer:
The first step in speciation is the separation of two populations from a single original population, known as allopatric speciation.
Step-by-step explanation:
The first step in the process of speciation is usually the separation of two populations from a single original population. This separation can occur due to geographic barriers such as mountains, rivers, or oceans, leading to allopatric speciation. Once the populations are geographically isolated, they can evolve independently and develop distinct characteristics.
An example of allopatric speciation is the case of squirrels on opposite sides of the Grand Canyon. The populations became reproductively isolated due to the barrier created by the canyon, resulting in the formation of different species over time.