Question

Development of hybrid varieties of plants and better milk yielding varieties of cows is an example of
A. Natural selection
B. Artificial selection
C. Mutation
D. Divergent evolution

Answer 1

Hint: Hybrids are formed from fusion of two different species, which have some advantages over original species.

Complete Answer:
- Natural selection is the process of adaptation of organisms to changing environment by bringing changes in their genetic constitution. But due to this one cannot have desired results yield in case of cow and desired variety in case of plants.
- Therefore, natural selection cannot develop hybrid plants and better varieties of cows. Mutation is a sudden heritable change in the form of genes.
- Mutation arises when there is adaptation to environmental conditions.Hence, mutation cannot give rise to desired hybrids.
- Artificial selection is the process by which desired traits for breed can be generated in plants and animals consisting of improved characters. Plants which have drought resistance genes are inserted into other plant varieties for better results.
- The technique used for generating improved quality breeds or varieties is genetic engineering. Example, for better milk yield cows producing more and healthy milk is interbreed with low productivity breeds.

Therefore, the correct answer is option B. Artificial selection.

Additional information: Genetic engineering is the technique by which a gene of interest is then incorporated in the host. This technique is widely used for producing pharmaceutical products, animal breeding, plant breeding. A well known example of genetic engineering is production of Humulin which is genetically engineered insulin.

Note: Such artificial selection is useful for human welfare. Many plant varieties are produced by artificial selection which includes, wide mustard, Brassicas, cabbage, broccoli,etc.