Q.1 Which one of the following most accurately describes the process of natural selection?
(A) Selection of one species over a competing species
(B) Selection of individuals that successfully defend themselves against enemies
(C) Selection of individuals that produce more than the average number of offspring
(D) Selection of individuals that are more attractive to the opposite sex

Natural selection is the process where individuals with traits that enhance survival and reproduction pass on more genes to the next generation, driving evolutionary change. Option (C) most accurately describes this core mechanism.

Introduction

The natural selection process forms the foundation of Darwinian evolution, favoring individuals that produce more offspring in competitive environments. This MCQ tests core concepts for CSIR NET Life Sciences aspirants, emphasizing reproductive success over other traits. Mastering the natural selection process ensures clarity in evolutionary biology questions.

Option Analysis

Option (A): Species-Level Selection

This describes interspecies competition, like one species outcompeting another for resources, but natural selection operates on individuals within a population, not entire species. It overlooks genetic variation and heritability at the individual level.​

Option (B): Defense Against Enemies

Successful defense is one survival advantage, such as camouflage in prey species, yet natural selection encompasses broader factors like foraging efficiency or disease resistance. Limiting it to enemies ignores comprehensive fitness components.​

Option (C): More Offspring Than Average (Correct)

Natural selection selects individuals whose heritable traits enable higher reproductive success, measured by offspring that survive to reproduce. This differential reproduction shifts allele frequencies over generations, as seen in Darwin’s finches where beak size correlates with seed availability and breeding output.​

Option (D): Attractiveness to Opposite Sex

This refers to sexual selection, a subset of natural selection focusing on mating success, like peacock tails. However, it excludes non-sexual traits vital for survival and overall reproduction.​

Key Examples

• Peppered Moth: During industrialization, darker moths produced more offspring in polluted areas due to camouflage, exemplifying the natural selection process via survival and reproduction.​

• Antibiotic Resistance: Bacteria with resistance genes replicate faster under antibiotics, increasing their proportion in populations.​

• Galapagos Finches: Drought favored finches with larger beaks for tough seeds, leading to higher offspring numbers and trait prevalence.​