Climate Change and Organisms' Evolution

Living organisms are confronted with two different and opposing forces, one internal (genetic changes) and the other external (environmental changes). The outcome of this interaction is the evolution of organisms over time. The environmental changes that lead to the evolution of organisms can be divided into four groups: A. Ecological changes leading to Microevolution and natural selection become more or less stable in communities. B. Milankovitch cycles that cause severe changes in climate through cycles of twenty to one hundred thousand years, with the result of destruction of living communities and elimination of changes accumulated through ecological changes. C: Geological changes that cause the isolation of different populations of a species and cause major evolutionary changes (Macroevolution). D: Mass extinctions of organisms that averagely occur on the Earth every 26 million years and cause destruction of large groups of organisms in a very short time.