Short Answer
Natural selection is a natural process through which organisms that are better suited to their environment survive and reproduce more successfully than others. These organisms pass their useful traits to the next generation.
Over time, helpful traits become more common, while less useful traits decrease. This process slowly changes populations and helps species adapt to their environment and survive changing conditions.
Detailed Explanation :
Working of Natural Selection
Natural selection is one of the most important concepts in biology and is a key mechanism of evolution. It explains how living organisms change over long periods of time to become better adapted to their environment. Natural selection does not happen suddenly; it is a slow and continuous process that acts over many generations.
The idea of natural selection was proposed by Charles Darwin. According to this concept, nature itself selects organisms that are best suited to survive. Those organisms that cannot cope with environmental conditions are less likely to survive and reproduce.
Variation Among Organisms
Natural selection begins with variation.
In every population of plants or animals, individuals are not exactly the same. They show differences in size, color, shape, strength, speed, resistance to disease, and many other traits. These variations arise due to genetic differences and are passed from parents to offspring.
Some variations are helpful, some are neutral, and some may be harmful depending on the environment.
Struggle for Existence
Living organisms produce more offspring than the environment can support.
There is limited food, space, water, and other resources. As a result, organisms must compete with each other to survive. This competition is called the struggle for existence.
Only those individuals that are better adapted to their environment can successfully survive this struggle.
Survival of the Fittest
The term “survival of the fittest” explains the core of natural selection.
Here, “fittest” does not mean strongest, but best suited to the environment. Organisms with helpful traits such as better camouflage, sharper senses, stronger immunity, or efficient use of food are more likely to survive.
Less adapted organisms are more likely to die before reproducing.
Reproduction and Inheritance
Surviving organisms reproduce and pass their traits to the next generation.
The useful traits that helped parents survive are inherited by their offspring. Over many generations, these traits become more common in the population.
At the same time, traits that do not help survival gradually disappear.
Role of Environment
The environment plays a major role in natural selection.
Changes in climate, food availability, predators, and diseases affect which traits are useful. A trait that is helpful in one environment may be useless or harmful in another.
Thus, natural selection depends on environmental conditions.
Gradual Change Over Time
Natural selection works slowly.
Small changes accumulate over long periods of time. These gradual changes may lead to noticeable differences in a population. Eventually, a population may become so different that a new species is formed.
This explains how biodiversity develops on Earth.
Examples of Natural Selection
Natural selection can be observed in many organisms.
Animals with protective coloring survive better from predators. Plants with deeper roots survive drought better. Bacteria that are resistant to antibiotics survive treatment and multiply.
These examples show natural selection in action.
Natural Selection and Adaptation
Natural selection leads to adaptation.
Adaptation means developing features that improve survival and reproduction. These adaptations can be structural, physiological, or behavioral.
Through natural selection, organisms become better adapted to their environment over time.
Natural Selection and Extinction
Natural selection can also lead to extinction.
If organisms cannot adapt to rapid environmental changes, they may disappear. Extinction occurs when no individuals survive to reproduce.
This highlights the importance of adaptation for survival.
Conclusion
Natural selection works by favoring organisms with traits that help them survive and reproduce in a given environment. These traits are passed to future generations, leading to gradual changes in populations. Over time, natural selection results in adaptation, evolution, and diversity of life. It is a natural and continuous process that explains how living organisms survive, change, and develop on Earth.