01Diversity as insurance
Populations with more genetic variation are more likely to survive environmental change, disease and new predators. Low-diversity populations (cloned bananas, inbred cheetahs) can be devastated by one pathogen.
The Irish potato famine happened partly because potatoes were genetically uniform.
02Notebook box
More alleles → more chance some individuals survive change.
Worked example: Why are monoculture crops risky? → No variation for resistance; one disease can destroy the whole crop.