Introduction

In ecology, species are often classified along a continuum from r-selection to K-selection based on their reproductive strategies and adaptations to their environments. While r-selected species thrive in unpredictable habitats by reproducing rapidly, K-selected species are adapted for stability and efficiency, investing heavily in fewer offspring and long-term survival. Understanding the hallmark features of K-selected species is essential for grasping population dynamics and conservation strategies.

What Are K-Selected Species?

K-selected species are those that have evolved to maximize survival and competitive ability in environments where population sizes are near the ecosystem’s carrying capacity (K). These environments are typically stable, with intense competition for limited resources.

Core Characteristics of K-Selected Species

Let’s examine the options to identify the defining trait:

(1) High Intrinsic Rate of Growth

• Not characteristic of K-selected species.

• K-selected species typically have a low intrinsic rate of growth because they invest more in individual offspring and reproduce less frequently.

(2) Small Size and Large Number of Offspring

• Not characteristic of K-selected species.

• These features are typical of r-selected species, which focus on quantity over quality.

(3) First Reproduction at Later Stage of Life

• Correct!

• K-selected species mature slowly and reproduce later in life. This delayed reproduction allows them to grow larger, develop survival skills, and invest more in each offspring.

• Examples include elephants, whales, humans, and many large mammals and birds.

(4) Short Life Span

• Not characteristic of K-selected species.

• K-selected species generally have longer life spans, enabling them to reproduce multiple times over their lives.

Why Delayed Reproduction Is Key

• Survival Advantage: Delayed reproduction allows individuals to reach a larger size and gain experience, increasing their survival and reproductive success.

• Parental Investment: With fewer offspring produced at a time, K-selected species can afford to invest more resources and care in each, enhancing offspring survival.

• Population Stability: These traits help maintain stable population sizes near the carrying capacity, reducing the risk of boom-and-bust cycles.

Comparison Table: r-Selected vs. K-Selected Species

Examples of K-Selected Species

• Elephants: Long gestation, few calves, extensive parental care.

• Whales: Slow to mature, few offspring, high survival rates.

• Humans: Delayed maturity, long childhood, significant parental investment.

• Large birds: Eagles and albatrosses, with long life spans and few chicks.

Conclusion

The characteristic feature of K-selected species is first reproduction at a later stage of life. This delayed maturity is part of a broader strategy focused on quality over quantity, ensuring offspring survival in competitive, stable environments.

Correct answer:
(3) First reproduction at later stage of life