Glossary of "Ecology (6th ed.)" by Krebs (2009)
- the ability of a particular genotype or phenotype to leave descendants in future generations, relative to other organisms.
Glossary of "Life (9th ed.)" by Sadava et al. (2011)
- The contribution of a genotype or phenotype to the genetic composition of subsequent generations, relative to the contribution of other genotypes or phenotypes. (See also inclusive fitness.)
Glossary of "Evolution (4th ed.)" by Futuyma & Kirkpatrick (2017)
- The success of an entity in leaving descendants to the next generation. Most often refers to the average contribution of an allele, genotype, or phenotype; canalso refer to the contribution of a specific entity (e.g., an individual). See also relative fitness.
- Futuyma, D. J. & Kirkpatrick, M. 2017. Evolution, 4th ed. -xviii + 602 pp. Sinauer Associates, Inc., Sunderland.
- Krebs, C. J. 2009. Ecology, 6th ed. -xvi + 655 pp. Pearson Benjamin Cummings, San Francisco.
- Sadava, D., Hillis, D. M., Heller, H. C. & Berenbaum, M. R. 2011. Life: The Science of Biology, 9th ed. -xliv + 1266 pp. Sinauer Associates, Inc., Sunderland.