Glossary of "Cladistics (2nd ed.)" by Kitching et al. (1998)
- The number of steps required to account for the transformation of one character state into another on a cladogram.
Glossary of "Evolution (4th ed.)" by Futuyma & Kirkpatrick (2017)
- A reduction in fitness caused by a correlated effect of a feature that provides an increment in fitness (i.e., a benefit).
- Futuyma, D. J. & Kirkpatrick, M. 2017. Evolution, 4th ed. -xviii + 602 pp. Sinauer Associates, Inc., Sunderland.
- Kitching, I. J., Forey, P. L. Humphries, C. J. & Williams, D. M. 1998. Cladistics, 2nd ed.: the Theory and Practice of Parsimony Analysis. -xii + 228 pp. Oxford University Press, New York.