Exam 3: Living Primates

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Being k-selected refers to a reproductive strategy adopted by certain species in ecology, as described by the r/K selection theory. This theory was proposed by ecologists Robert MacArthur and E.O. Wilson in the 1960s and is used to describe how species allocate resources to reproduction and survival.

In the r/K selection theory, the "r" stands for the intrinsic rate of increase (reproduction), while "K" stands for the carrying capacity of the environment. Species that are k-selected tend to live in stable environments where the population size is near the carrying capacity. These species have evolved traits that are advantageous under such conditions.

Characteristics of k-selected species include:

1. **Longer Lifespans**: K-selected species often have longer lifespans, which allows them to invest more time and energy into their offspring.

2. **Fewer Offspring**: They produce fewer offspring compared to r-selected species, but provide a high level of parental care to ensure that a larger percentage of those offspring reach maturity.

3. **Late Reproduction**: These species tend to reproduce later in life, and may have fewer reproductive events over their lifetime.

4. **High Investment in Offspring**: There is a significant investment in each individual offspring, which may include long gestation periods, extended parental care, and teaching of survival skills.

5. **Greater Competitive Ability**: K-selected species are often strong competitors in crowded niches, and their populations are regulated by competition rather than by external factors such as predation or climate events.

6. **Stable Population Size**: The population size of k-selected species tends to be stable and close to the carrying capacity of the environment, with fluctuations being less dramatic than in r-selected species.

Examples of k-selected species include large mammals like elephants, primates, and whales, as well as some long-lived plants like oak trees. These species are contrasted with r-selected species, which live in unstable environments, reproduce quickly and in large numbers, and have a high mortality rate with little parental care.

It's important to note that the r/K selection theory is a simplification and that many species do not fit neatly into either category. Instead, they may exhibit a range of traits along the r-K continuum. Additionally, the theory has been supplemented by more complex models of life-history evolution as the field of ecology has advanced.