Density-Sensitive Selection Explained

The question asks to identify the term for selection favoring traits that are advantageous when population density is high.

Understanding Selection Strategies

Ecological and evolutionary biology describes different selection strategies based on population density and environmental conditions. We need to find the strategy specifically linked to high population densities.

• Semelparity: Refers to organisms that reproduce only once in their lifetime. This is a life history strategy, not directly tied to density-dependent selection.
• k-selection: This strategy occurs in stable, high-density populations. Organisms focus on traits that improve competitive ability and resource efficiency, like slower growth and fewer, larger offspring. This aligns with selection favored at high densities.
• Natural selection: This is the broad, overarching mechanism of evolution where organisms better adapted to their environment tend to survive and produce more offspring. It encompasses various specific types of selection, including density-dependent ones.
• r-selection: This strategy is common in unstable, low-density environments. It favors traits that maximize rapid reproduction, like fast growth, early maturity, and producing many small offspring, often before resources become scarce.

Identifying the Correct Term

k-selection is the specific term for selection pressures that are strongest in populations near their carrying capacity (high density). Traits favoured under k-selection help organisms survive and reproduce efficiently when competition for limited resources is intense.

Therefore, selection for traits sensitive to population density and favoured at high densities is known as k-selection.