In this activity, you will research the genetic diversity in two fish variants. The Mexican tetra (Astyanax mexicanus) has two notable variations: the surface variety and the blind cave fish variety. In this activity, you’ll use credible websites to find the following information about these two fish: What type of habitat does each fish live in?

How do their physical characteristics differ?

How are they similar?

Can the two types mate with each other?

Why are their characteristics advantageous to their environments?

When you’ve found the information, answer the following questions.

Part A :

What are the similarities and differences between the two fish varieties?

Part B:

Do you think these fish are an example of natural selection among two populations of the same species? Explain your answer.

Part C:

Explain how the characteristics of the two types of fish relate to the genetic diversity of the species.

Part A-One of the variations have eyes as well as some pigmentation on them. They live near the surface of the water. The other variation does not have eyes and are often albinos. I found that these fish live in deep, dark caves.

Part B-Yes. I think that these fish are an example of natural selection. The blind fish live in caves and eyes take up energy that could be used somewhere else in the fish. So, they developed into fish with no eyes, allowing them to function more efficiently.

Part C- As a species, they have genetic diversity because the two populations have separate genes. The two fish types developed different traits because of their separate habitats.

Explanation:

1) gene flow

- it is described as the transfer of genes from one population to another population so that frequency of gene is increased.

-a zebra migrates to join a different herd of zebras.

2) natural selection

- a mechanism of evolutionary change in which individuals with advantageous traits survive and reproduce whereas the others ( those that can not adapt) eliminate from the population.

-competition for sunlight leads to taller trees.

3) mutation

- permanent change in the nucleotide sequence of dna ( genetic material) that could have harmful or useful consequences.

-the dna of a snake changes to make its venom stronger.

4) genetic drift - it is a random phenomenon ( that occurs by chance such as fire) that results in change in the gene frequency in a small population.    

-a grassfire randomly sweeps through a population of buffalo and kills most of the animals.

explanation:

it will increase due to the time span