heridity and evelution
why variations are important?how variations occur.how we can see variations
A species must have genetic variation (different alleles at the same gene positions in DNA) in order to adapt to changing environmental conditions so the species survives.
Imagine that every member of a population is genetically identical. Then a disease, predator, climate or some other factor attacks that population. Every member of that population is equally susceptible and all or most will die – end of that population or species.
What happens when there is little genetic variation is that the species becomes weak. This is why inbreeding in domesticated animals (or people) is a bad thing. Genetic diversity is a guarantee against all of a species being equally affected by something bad happening to them.
This is a risk we run in growing crops from seeds that have little genetic diversity. One insect, mold, disease or climate event can wipe out the entire crop.