88. There are diverse ecological adaptive strategies in which some organism are favored due to more energy investment on their reproductive rate while other are favoured on basis of
    investing large energy for homeostasis. Such a selection strategies are termed as
    (1) r- and K-selection
    (2) Logistic and exponential selection
    (3) Directional and disruptive selection
    (4) Kin and group selection

Introduction

Ecological systems are filled with a remarkable variety of life-history strategies. Some species thrive by reproducing quickly and in large numbers, while others succeed by investing more energy in survival, growth, and maintaining internal balance (homeostasis). These contrasting approaches are explained by the concepts of r-selection and K-selection, foundational theories in ecology that describe how organisms adapt to their environments.

What Are r- and K-Selection Strategies?

r-Selection

• Focus: Maximizing reproductive rate

• Traits: Early maturity, short lifespan, large number of small offspring, minimal parental care

• Environment: Unstable or unpredictable, where rapid population growth is advantageous

• Examples: Insects (like flies and mosquitoes), annual plants, many small rodents

K-Selection

• Focus: Maximizing survival and competitive ability

• Traits: Late maturity, long lifespan, few large offspring, extensive parental care, high investment in homeostasis

• Environment: Stable and crowded, where competition for resources is intense

• Examples: Elephants, whales, humans, many large mammals and birds

The Core Principle

• r-selected species invest most of their energy in producing as many offspring as possible, betting on numbers to ensure that some survive unpredictable conditions.

• K-selected species allocate more energy to each individual, ensuring better survival rates through parental care, defense, and physiological stability (homeostasis).

Why Are These Strategies Important?

• Adaptation to Environment:
  r-selection is favored in environments where conditions change rapidly or catastrophes are common, making rapid reproduction the best survival tactic.
  K-selection is favored in stable environments where resources are limited and competition is high, making efficiency and survival paramount.

• Population Dynamics:
  r-selected species often show boom-and-bust population cycles, while K-selected species maintain more stable populations near the ecosystem’s carrying capacity (K).

Evaluating the Options

Given the question and the answer choices:

1. r- and K-selection

   • Correct.

   • These terms directly describe the strategies of investing energy in reproduction (r-selection) versus homeostasis and survival (K-selection).

2. Logistic and exponential selection

   • These refer to population growth models, not adaptive strategies.

3. Directional and disruptive selection

   • These are types of natural selection, not specific life-history strategies.

4. Kin and group selection

   • These refer to evolutionary mechanisms involving related individuals or groups, not energy investment strategies.

Conclusion

The selection strategies where some organisms invest more energy in their reproductive rate, while others invest in homeostasis and survival, are termed r- and K-selection. These concepts help ecologists understand how species adapt to different environments and why certain life-history traits evolve.

Correct answer:
(1) r- and K-selection