Biology Quote by Ronald Fisher
“We may consequently state the fundamental theorem of Natural Selection in the form: The rate of increase in fitness of any organism at any time is equal to its genetic variance in fitness at that time.”
About This Quote
Source Book: The Genetical Theory of Natural Selection, 1930
Fitness rises proportionally to how much genetic variation exists in a population at a given moment.
In simple terms: More genetic variation means faster fitness improvement.
Preserve genetic diversity.
Themes
Mood
Type
When to use this quote
- conservation breeding
- crop improvement
- medical genetics
- environmental change
Key Concepts
Questions to Reflect On
- How does maintaining diversity affect long‑term adaptation?
- What limits the rate of fitness increase?
Assumes additive genetic effects and ignores epistasis.