Answer
Observations:
1. All species have such great potential fertility that their population size would increase exponentially if all individuals that are born go on to reproduce successfully.
2. Populations tend to remain stable in size, except for seasonal fluctuations.
3. Environmental resources are limited.
4. Individuals of a population vary extensively in their characteristics (to the extent that no two individuals are exactly alike).
5. Much of this variation is heritable.
Work Step by Step
Interferences:
1. Due to the limited resources, production of more individuals than the environment can suppot leads to a struggle for existence among individuals - often with only a fraction of offspring surviving through each generation.
2. It is not a random process that determines which individuals will reproduce and which will not, as it depends in part on the genetic constitution of those surviving individuals. Those individuals whose inherited characteristics best suit them to that environment in which they live are likely to have more offspring than those that are not so well adapted to the environment.
3. This unequal ability between individuals to survive and reproduce will lead to gradual evolution of the population, with favourable characteristics accumulating over the generations.
