Question

During the evolutionary synthesis, biologists conclusively identified natural selection, gene flow, genetic drift, and mutation as the major causes of evolution within species. Using the scientific definition of evolution, explain how these forces cause populations, species, and higher taxa to evolve.

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.

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.

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

Mutations are the sources genetic variation. All mutations do no leads to evolution. Therefore, mutations from one generation to the another depends on other factors such as natural selection.

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.