R/K selection theory

A North Atlantic right whale with solitary calf. Whale reproduction follows a K-selection strategy, with few offspring, long gestation, long parental care, and a long period until sexual maturity.

In ecology, r/K selection theory relates to the selection of combinations of traits in an organism that trade off between quantity and quality of offspring. The focus on either an increased quantity of offspring at the expense of reduced individual parental investment of r-strategists, or on a reduced quantity of offspring with a corresponding increased parental investment of K-strategists, varies widely, seemingly to promote success in particular environments. The concepts of quantity or quality offspring are sometimes referred to as "cheap" or "expensive", a comment on the expendable nature of the offspring and parental commitment made.[1] The stability of the environment can predict if many expendable offspring are made or if fewer offspring of higher quality would lead to higher reproductive success. An unstable environment would encourage the parent to make many offspring, because the likelihood of all (or the majority) of them surviving to adulthood is slim. In contrast, more stable environments allow parents to confidently invest in one offspring because they are more likely to survive to adulthood.

The terminology of r/K-selection was coined by the ecologists Robert MacArthur and E. O. Wilson in 1967[2] based on their work on island biogeography;[3] although the concept of the evolution of life history strategies has a longer history[4] (see e.g. plant strategies).

The theory was popular in the 1970s and 1980s, when it was used as a heuristic device, but lost importance in the early 1990s, when it was criticized by several empirical studies.[5][6] A life-history paradigm has replaced the r/K selection paradigm, but continues to incorporate its important themes as a subset of life history theory.[7] Some scientists now prefer to use the terms fast versus slow life history as a replacement for, respectively, r versus K reproductive strategy.[8]

  1. ^ "r and K selection". www.bio.miami.edu. Retrieved 2020-10-27.
  2. ^ Pianka, E.R. (1970). "On r and K selection". American Naturalist. 104 (940): 592–597. doi:10.1086/282697. S2CID 83933177.
  3. ^ MacArthur, R.; Wilson, E.O. (1967). The Theory of Island Biogeography (2001 reprint ed.). Princeton University Press. ISBN 978-0-691-08836-5.
  4. ^ For example: Margalef, R. (1959). Mode of evolution of species in relation to their places in ecological succession. XVTH International Congress of Zoology.
  5. ^ Roff, Derek A. (1993). Evolution Of Life Histories: Theory and Analysis. Springer. ISBN 978-0-412-02391-0.
  6. ^ Stearns, Stephen C. (1992). The Evolution of Life Histories. Oxford University Press. ISBN 978-0-19-857741-6.
  7. ^ Cite error: The named reference ReznickEA2002 was invoked but never defined (see the help page).
  8. ^ Jeschke, Jonathan M.; Kokko, Hanna (2009). "The roles of body size and phylogeny in fast and slow life histories". Evolutionary Ecology. 23 (6): 867–878. doi:10.1007/s10682-008-9276-y. S2CID 38289373.