Question

Describe and give an example of four (4) other factors besides natural selection that could lead to evolution (changes in allele frequency at the population level).

Answer 1

Evolution is defined as change in genetic makeup of population over generations.

Population may change because of forces of evolution. It includes

- Natural Selection
- Genetic Drift
- Mutations
- Gene Flow.
- Non-Random Mating

1) Evolution because of natural selection depends on fitness. It means individuals with more heritable traits and which makes them more fit will survive in given environment. It means individual who is better to survive and reproduce will produce more offspring than other members of the population.

2) Genetic drift results in evolution by chance events due to sampling error. It randomly select alleles for the next generation.

Example:

A plant has blue or yellow flowers and during fire, yellow flowers are burned and thus blue is now the dominant allele. Therefore, plant reproduces only blue flowers.

3) Mutations are the sources genetic variation. It is defined as error while copying the DNA. All mutations do no leads to evolution. It depends on the type of cell and the amount of DNA affected by mutation. Therefore, mutations from one generation to the another depends on other factors such as natural selection.

Example:

In hunan beings, bone density is governed by low-density lipoprotein receptor-related protein 5 and mutations can increases its function, and thus causing increases bone density.

4) Gene flow means movement of genes out or in of a population. It is because of movement of individual organisms or their gametes such as eggs and sperm.

Example:

Blue-eyed people from one place move to another place where people have brown eyes and during mating, some children will now have blue eyes. It shows flow of genes.


5) Non-Random Mating is defined as strategically choosing mates and est genes are transferred. It is called sexual selection.

Example:

Females fron different organisms do not mate with a random male, even their mating choice based on physical traits.