Question

1. Variation is key to the survival of life on this planet. Why is this, where does variation come from, and what helps select for it in a population of animals?

Answer 1

Ans. Variations at genetic level leads to morphological variations in organisms. This variation is required for the survival of life on this planet. It is because the environmental conditions of the planet changes from earlier times. Temperature, gaseous content change and the organisms need to change to cope with the changing environment. If the earlier organisms do not change genetically and morphologically the organisms won't be able to survive. It is because the protein function depends on temperature, phynotypic changes including skin hair, lipid content, presence of cuticle (in case of members of arthropoda), all these changes need to be made to survive on this planet. The variations are created through mutations ( random changes in nucleotide sequences in DNA) leading to altered protein function. The ultimate source of variations is mutation. Natural selection favours the selection of organisms with higher fitness ( ability to produce more viable offsprings). Natural selection leads to the survival of more fit individuals in the changing environment.