Natural selection is the process by which organisms with traits that make them better suited to their environment are more likely to survive, reproduce, and pass on their genes to the next generation.

(a) Genetic Variation Within Populations

• In any species, individuals show genetic variation – differences in features caused by different alleles (versions of genes).
• Example: In a population of rabbits, some may have brown fur, others white.
• This variation gives nature options to “choose from”.

(b) Production of Many Offspring

• Most organisms produce more offspring than the environment can support.
• Example: A single oak tree may produce thousands of acorns — but only a few grow into mature trees.
• This overproduction leads to intense competition among offspring.

(c) Struggle for Survival & Competition

• Resources like food, water, shelter, and mates are limited.
• Example: In dry regions, gazelles compete for access to limited watering holes.
• Only those with better traits – speed, strength, or camouflage – are more likely to survive.

(d) Greater Chance of Reproduction by Better Adapted Individuals

• Individuals with traits suited to their environment are more likely to reproduce successfully.
• Example: Insect-eating birds with slightly longer beaks may reach more food and stay healthier – giving them an edge in mating and survival.
• These individuals pass on their beneficial traits to the next generation.

(e) Passing on Alleles to the Next Generation

• The helpful alleles are passed down and become more common in the population over time.
• Example: In peppered moths, the dark-colored variant became more common during the Industrial Revolution because it blended into soot-covered trees — offering camouflage from predators.
• This is how a species gradually becomes better adapted to its surroundings.