3.29 Species Variation

3.29 Understand that variation within a species can be genetic, environmental, or a combination of both.

Variation = differences that we can see in the phenotype's of individuals. So basically differences in how things appear. It is possible to measure these differences and show them in graphic form.

An individuals have a phenotype, and the appearance of an individual is because of their genotype which will be modified by the environment.

Phenotype = Genotype + Environment

Variation in a population is the variation in all these individuals (talked about above).

V population = V genotype + V environment

So variation in the population; is because of the variation in genotype and because of the variation in the environment in which the species occupy and develop in.

Class 1: Variation in the population/ species is solely down to variation in genotypes. This is discontinuous variation.
- An example of this would be blood groups. Individuals would be typically, A, AB, O or B

Class 2: Variation in the population/ species is down to variation in genotypes and variation in the environment. This is continuous variation.
- An example of this would be an individuals height. One may inherit genes to be very tall, but this will be modified by changes in the environment such as the quality of ones diet.

Class 3: Variation in the population/ species solely down to variation in the environment.This cannot be inherited.
- An example of this would be the home language which you speak. You do not inherit the ability to speak English or French. You speak one of these languages because of your parents or because the place you are born and grow up.