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 upon either increased quantity of offspring at the expense of individual parental investment, r-strategists, or reduced quantity of offspring with a corresponding increased parental investment, K-strategists, varies widely, seemingly to promote success in particular environments.
...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.[4][5] A life-history paradigm has replaced the r/K selection paradigm but continues to incorporate many of its important themes.[6]
... r comes from rate while K comes from carrying capacity. In German, the word for capacity is Kapazität and K stands for the "Kapazitätsgrenze" (capacity limit).
...In unstable or unpredictable environments, r-selection predominates as the ability to reproduce quickly is crucial. Among the traits that are thought to characterize r-selection are high fecundity, small body size, early maturity onset, short generation time, and the ability to disperse offspring widely. (Fecundity means fruitfulness and fertility).
...By contrast, K-selected species display traits associated with living at densities close to carrying capacity, and typically are strong competitors in such crowded niches that invest more heavily in fewer offspring, each of which has a relatively high probability of surviving to adulthood (i.e., low r, high K).
By contrast, K-selected species display traits associated with living at densities close to carrying capacity, and typically are strong competitors in such crowded niches that invest more heavily in fewer offspring, each of which has a relatively high probability of surviving to adulthood (i.e., low r, high K).
In stable or predictable environments, K-selection predominates as the ability to compete successfully for limited resources is crucial and populations of K-selected organisms typically are very constant in number and close to the maximum that the environment can bear (unlike r-selected populations, where population sizes can change much more rapidly).
Traits that are thought to be characteristic of K-selection include large body size, long life expectancy, and the production of fewer offspring, which often require extensive parental care until they mature. Organisms whose life history is subject to K-selection are often referred to as K-strategists or K-selected.[9] Organisms with K-selected traits include large organisms such as elephants, humans and whales, but also smaller, long-lived organisms such as Arctic terns.[10]
Is that more than you ever wanted to know about r/K selection theory? so where are we now in the United States? r, or K?
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