9.Two species of sunflowers of a mountain. For a while, the two sunflower populations evolve separately.With the climatic changes , an animal population crosses from one side of the mountain chain to the other,bringing some sunflower pollen with it. Identify the evolutionary mechanism that is at work in this example , and explain your answer.

## Step 1<br />The problem describes a situation where two species of sunflowers are evolving separately on either side of a mountain. This is an example of allopatric speciation, a type of speciation that occurs when biological populations of the same species become isolated due to geographical changes such as mountains or rivers.<br /><br />## Step 2<br />The sunflower populations on either side of the mountain are evolving separately, which means they are not exchanging genetic material. This is a form of reproductive isolation, which is a key factor in speciation.<br /><br />## Step 3<br />However, the situation changes when an animal population crosses from one side of the mountain to the other, carrying some sunflower pollen with it. This introduces new genetic material into the previously isolated sunflower populations, leading to gene flow.<br /><br />## Step 4<br />Gene flow is the transfer of genetic variation from one population to another. It can occur when individuals from different populations interbreed, leading to the mixing of genetic material.<br /><br />## Step 5<br />In this case, the animal population acts as a vector, carrying pollen from one sunflower population to the other. This introduces new genetic material into the previously isolated sunflower populations, leading to gene flow.