1. 4 Factors Required for Natural Selection

2. 1. Variation
Diversity in a population by random mutations

3. 2. Overpopulation More offspring are born than can survive
They may lay from 200 to 2000 eggs in a single week in the water. A lot of the eggs and tadpoles do not survive due to fish eating on them.

4. 3. Selection Pressure Survival depending on fitness/adaptations
The struggle for survival

5. 4. Time
Evolution takes a long time because mutations are random and have to be advantageous

6. Natural Selection Lab