each complete turn of the helix (Watson, 1965).Diagram to illustrate the double helix of DNA with the two-polynucleotide chains linked by complementary base-pairs (Adenine (A) with Thymine (T), and Guanine (G) with Cytosive (C). Replication occurs when the two strands separate and both act as templates on which new complementary strands are formed (Moriarty, 62).Occasionally, something goes wrong with the replication process and one or more genes may be altered, lost or gained. These changes, or mutations are usually less favorable to the organism than the original gene, and are often sufficiently unfavorable to be lethal. Nevertheless, mutations in the reproductive cells are of crucial importance: these are in favorable, the source of new genetic variation in subsequent generations. This knowledge about gene structure and function modifies the Mendelian view of inheritance.Now, after the brief introduction and history of genetics it is time to consider the relevance of ecological genetics to pollution. Most current problems of pollution occur on a much shorter time-scale than that required for the evolution of new species. The critical difference between evolutionary change and that wrought by pollution is the speed: populations can disappear very rapidly from pollution and if unchecked, we would have a very impoverished fauna and flora (Moriarty, 81).One very popular example of the effects of pollution on wildlife, and perhaps the most striking evolutionary change over to be actually witnessed was the occurrence of melanism in moths. This effect is commonly associated with industrial development. White moths would rest on white lichen on trees and were well-nigh visible on them. But with industrial pollution (between 1848 and 1990) lichen turned a black color exposing and making the white moth (f. typica) prey to birds. Birds posed a selective pressure against the white moths. Now black moths were favored evolutionary. This is known ...
