LIFE SCIENCE

Detailed explanation-1: -The organisms exhibit different characteristics due to different genotypes (variation). If these characteristics are favoured by the natural environment, the organisms with these variations survive and propagate, and may form different species. Thus, evolution is the outcome of natural selection.

Detailed explanation-2: -Natural selection is the process through which species adapt to their environments. It is the engine that drives evolution.

Detailed explanation-3: -Natural selection is an inevitable outcome of three principles: most characteristics are inherited, more offspring are produced than are able to survive, and offspring with more favorable characteristics will survive and have more offspring than those individuals with less favorable traits.

Detailed explanation-4: -Four (4) conditions for natural selection. Four conditions are needed for natural selection to occur: reproduction, heredity, variation in fitness or organisms, variation in individual characters among members of the population. If they are met, natural selection automatically results.

Detailed explanation-5: -Natural selection on polygenic traits can affect the distributions of phenotypes in three ways: directional selection, stabilizing selection, or disruptive selection.