87. The characteristic of a population with low value of intrinsic growth (r = 0.2) is
    (1) Late sexual maturity and small clutch size
    (2) Early sexual maturity and small clutch size

(3) Late sexual maturity and large clutch size
(4) Early sexual maturity and large clutch size

Introduction

Intrinsic growth rate (r) is a fundamental concept in population ecology, reflecting how quickly a population can increase under ideal conditions. Populations with a low intrinsic growth rate (for example, r = 0.2) tend to grow slowly and exhibit specific life-history traits. Understanding these characteristics helps explain the differences between r-selected and K-selected species and their adaptations to various environments.

What Is Intrinsic Growth Rate?

The intrinsic growth rate (r) measures the potential for population increase when resources are unlimited and environmental resistance is minimal. Species with a high r value reproduce rapidly and in large numbers, while those with a low r value grow slowly and invest more in individual offspring.

Characteristics of Populations With Low r

Populations with a low intrinsic growth rate typically exhibit the following features:

• Late Sexual Maturity: Individuals take longer to reach reproductive age, often investing more time in growth and development before reproducing.

• Small Clutch Size: These species produce fewer offspring per reproductive event, focusing on quality and survival rather than quantity.

• Longer Lifespans: Many low-r species live longer, allowing for multiple reproductive events over their lifetime.

• High Parental Investment: Offspring receive more care and resources, increasing their chances of survival.

These traits are hallmarks of K-selected species, which are adapted to stable environments where competition for resources is intense and population sizes are close to the carrying capacity (K).

Evaluating the Options

Let’s analyze the provided choices:

1. Late sexual maturity and small clutch size

   • Correct.

   • These are classic features of populations with a low intrinsic growth rate, reflecting a strategy focused on survival and competitive ability rather than rapid population increase.

2. Early sexual maturity and small clutch size

   • Early maturity is typical of fast-growing, r-selected species, not those with low r.

3. Late sexual maturity and large clutch size

   • Large clutch sizes are more typical of r-selected species, not those with low r.

4. Early sexual maturity and large clutch size

   • Both features are associated with high intrinsic growth rates (r-selected strategy).

Why These Traits Matter

Populations with low r values are less likely to experience rapid population booms and busts. Instead, they grow slowly and maintain stability over time, making them more resilient to environmental fluctuations but slower to recover from declines.

Conclusion

A population with a low intrinsic growth rate (r = 0.2) is characterized by late sexual maturity and small clutch size. These traits are typical of K-selected species, which prioritize survival and long-term stability over rapid reproduction.

Correct answer:
(1) Late sexual maturity and small clutch size