1. Factors that Affect the Process of Evolution

2. There are four factors that affect the process of evolution…

3. 1. Overproduction: The potential for a species to increase in number
(More individuals are born in a population than will survive)

4. Natural Selection – High Reproductive Potential
Darwin observed that organisms have the potential for very high fertility.
Organisms have the potential to produce, and often do produce large numbers of offspring.
Population size would quickly become unmanageable if all of the offspring survived.

5. 2. Individual Variation:
The heritable genetic variation of individuals in a species due to mutation and sexual reproduction
(Individuals in a population are different)

6. Natural Selection- Variety
In any population of organisms there is natural variation.
Some of these variations will allow the organisms possessing them to survive and reproduce better than those without these particular traits.

7. 3. Struggle for Existence:
Competition for limited resources
Individuals must compete for limited resources or must escape predators
Food, water, shelter, nesting sites, etc.

8. Natural Selection – Competition
If there are not enough resources for all of the individuals, there will be competition for those resources.
Survivors represent a small part of the individuals produced each generation.

9. 4. Survival of the Fittest:
The proliferation of those organisms that are better able to survive and reproduce in the environment
Those best adapted or “fit” to their environment or niche are more likely to survive

10. Natural Selection – Adaptation
The favored traits will spread through the population.
Over many generations, the species will become adapted to its environment.
Over very long periods of time, these changes can lead to the formation of a new species.