An organism's relative contribution of offspring to the next generation.
Darwinian fitness is lifetime reproductive success, including survival to reproduce, mating success and fecundity. Inclusive fitness also counts effects on relatives. Fitness is context-dependent and measured relative to others.
Common mistake: fitness is not physical strength.
An organism's relative contribution of offspring to the next generation.
Fitness is one of the 53 topics in Evolution. It is rated Intermediate, so it suits learners who already know the core vocabulary. Related topics in this area include Adaptation, Natural Selection, Sexual Selection.
An organism that is small but produces many surviving offspring is fitter than a large one that produces few.
Work through the Beginner topics in Evolution first, such as Evolution, Natural Selection, Charles Darwin, then return to Fitness. Intermediate topics assume the Beginner vocabulary.
The closest topics to Fitness are Adaptation, Natural Selection, Sexual Selection, Evolutionary Stable Strategy. Comparing them side by side is a good way to see how the ideas connect.
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Fitness. To practise the whole of Evolution, use the Evolution quiz.
Fitness: An organism's relative contribution of offspring to the next generation. Adaptation: A heritable trait that improves an organism's survival and reproduction in its environment. Read both side by side and note what each one explains.
Fitness is not physical strength.
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Adaptation and explain the difference aloud. Finally, take the Evolution quiz and come back to this page for any question you miss.
A heritable trait that improves an organism's survival and reproduction in its environment.
🦎 EvolutionIndividuals with traits better suited to their environment survive and reproduce more, passing those traits on.
🦎 EvolutionSelection arising from competition for mates or mate choice, creating traits like peacock tails.
🦎 EvolutionA strategy that, once common in a population, cannot be invaded by any rare alternative.
🦎 Evolution