What happens when members of a single species population are separated from the others? In the following, we will define allopatric speciation, how it occurs, and what different types there are. We will also provide examples of allopatric speciation and discuss what differentiates it from sympatric speciation.
What is the Definition of Allopatric Speciation?
Speciation occurs when populations of a species, due to certain factors, evolve to become new, distinct species. Allopatric speciation,commonly referred to as geographic speciation, occurs when populations are split due to geographic isolation.
You are viewing: Which Is The First Step In Allopatric Speciation
How Does Allopatric Speciation Occur?
Let’s delve deeper into allopatric speciation.
Allopatric Speciation Requires Geographical Isolation
When a population is geographically connected, its gene pool is relatively homogenous, meaning the allele frequencies among its members are similar. Its gene flow is unrestricted: individuals can move into new areas and mate with individuals there.
Read more : Which Of These Is The Summer Italian Delicacy Semifreddo
When populations of a species are geographically isolated, gene flow across the groups is restricted, and the allele frequencies between the groups become more different over time. Suppose the groups are separated for a long enough period of time. In that case, the differences between their alleles become greater due to the differences in their environment (climate, predation, food sources, and other factors). Eventually, new species may form.
Allopatric Speciation can be Summarized in the Following Steps:
-
Geographic changes cause a single species population to separate into two or more groups.
-
The physical separation prevents the two groups from interbreeding with each other.
-
The groups undergo genetic divergence: each group develops new, distinct traits based on the demands of their specific habitat or the genetic makeup of the parent population.
-
Over time, the groups evolve into reproductive isolation: they become so different that the members of each group no longer interbreed, even if they are in the same habitat at the same time.
Read more : Which Outlander Character Are You
Figure 1 shows an experiment demonstrating allopatric speciation in the fruit fly (Drosophila pseudoobscura). A single population was split into two: one group was fed starch-based food, while the other group was fed maltose-based food. Over time, the populations diverged. When the two groups were mixed, they no longer mated with the other group members.
This diagram shows how allopatric speciation occurred in a fruit fly experiment.
We have mentioned that geographical changes, such as the formation of valleys and rivers, can cause allopatric speciation. But human activities such as the construction of roads and highways and environmental pollution can displace species from their habitat and cause allopatric speciation.
What Are the Types of Allopatric Speciation?
There are two types of allopatric speciation: peripatric speciation and vicariant speciation. In this section, we will briefly discuss each type.
Peripatric Speciation
Peripatric speciation—also known as founder effect speciation—occurs when members of a population become isolated in a location peripheral to the main population and establish a new population. The new population will have alleles selected at random (not because they produced more favorable traits). At the same time, gene flow is restricted between the original and new populations.
Source: https://t-tees.com
Category: WHICH
