Q.Animal husbandry and plant breeding programmes are the examples of:
Animal husbandry and plant breeding programmes are classic examples of artificial selection, where humans choose which organisms to breed based on desired traits.
The question asks you to identify the evolutionary process that best describes what happens when farmers and breeders deliberately select and mate animals or plants to produce offspring with specific, useful characteristics. This is a core concept in understanding how human intervention can shape the inheritance of traits over generations.
To see why the answer is artificial selection, you first need to understand what natural selection is. In nature, environmental pressures — like predators, climate, or food availability — determine which individuals survive and reproduce. The traits that help an organism survive in its particular environment become more common in the population over time. This happens without any conscious choice; it is driven by the environment itself.
Artificial selection, by contrast, is driven by human choice. Instead of the environment acting as the selective force, a farmer or breeder decides which individuals get to reproduce. For example, if a farmer wants cows that give more milk, they will only allow the highest-yielding cows and bulls to breed. Over many generations, the average milk yield of the herd increases. The same logic applies to plant breeding: if you want wheat with larger grains, you save seeds only from the plants that produce the biggest grains and plant those the next season.
The NCERT textbook explicitly uses these very examples — animal husbandry and plant breeding — to illustrate artificial selection. It contrasts this with natural selection to show that the mechanism is the same (differential reproduction based on inherited traits), but the selecting agent is different: humans instead of nature.
A common point of confusion is thinking that because the traits are inherited, this is somehow "evolution" in the sense of creating new species. Artificial selection usually only changes the frequency of existing traits within a species — it does not typically produce new species, though it can lead to varieties that look very different from their wild ancestors (like the many breeds of dogs).
Now let us briefly consider why the other options are incorrect.
- Reverse evolution is not a standard scientific concept. Evolution does not have a "reverse" gear; populations do not revert to an ancestral state in a directed way. Even if a trait reappears, it is not the same as reversing the entire evolutionary process.
- Mutation refers to a random change in the DNA sequence. While mutations are the ultimate source of all new genetic variation, the deliberate breeding programmes do not cause mutations. They simply select among the variations that already exist (or that arise spontaneously).
- Natural selection is ruled out because the selective pressure here is not the natural environment but human choice. The traits being selected — high milk yield, large grain size, docile temperament — are often not advantageous in the wild. In fact, many domesticated traits would be a disadvantage if the animals had to survive on their own.
The key distinction to remember for exams is this: whenever humans consciously choose which individuals to breed based on desired traits, it is artificial selection. The NCERT uses the examples of cows, dogs, and crop plants to drive this point home.
In short, animal husbandry and plant breeding programmes are examples of artificial selection because they involve humans deliberately selecting and breeding organisms with desirable traits, rather than the environment acting as the selective force.
Unlock everything free for 14 days
- Full step-by-step solutions
- Concept-first explanations
- Methods, shortcuts & mistakes
- PYQ mapping + timed mock tests
Full access for 14 days. No credit card required.