Evolution Rules

Evolution is the biological concept often associated with the history of life on the planet or the origin of new species.  Evolution is also an important consideration for biologists focused on the interaction of living things in an ecosystem.  For these biologists, populations change over time periods that are measured by a few years, not thousands or millions of years.  Changes in crop pests can render control methods ineffective, so the study of pest evolution is important in crop management.

Knowing the following facts is the basis for understanding evolution.

1. Evolution rewards the successful individual and success means reproduction.  The more offspring an individual produces, the more biologically successful it is or has become.

2. Populations evolve. Individuals do not change their genetic makeup and evolve.  Groups of individuals that live in the same place at the same time can change their collective genetic makeup over time. That change is then passed on to succeeding generations.  This is evolution.

3.  Genetic variation among the individuals in a population is required before a population will evolve.  The variable genes must control traits that impact reproductive success.

4. Evolution requires a change in the environment that makes some individuals more successful than others.

5. The rate at which a population will evolve depends on the selection pressure imposed by the factor that has been changed in the environment. Selection pressure is the degree to which  the environmental factor is lethal.  There is a high level of selection pressure on a population when the environmental factor impacts the individuals’ reproductive success.

6. Sexually reproducing individuals pass on their genes, not their genotypes. Therefore, reproductively successful individuals can produce unsuccessful offspring which can slow the rate of population evolution.