Ultimately, evolution is the basis for the classification of organisms. Taxonomists attempt to look at the total pattern of natural diversity and try to understand how it came to be. Environmental limiting factors for the distribution and abundance of various life forms include presence of water, temperature, oxygen, salinity, marine depth and light penetration, and substrate type. As these parameters change in an environment, so does the type of organism found there as well as the relative abundance of that organism. Furthermore, climate, food availability, the existence of predators and competition in the area, as well as the existence of other members of the same species available for reproduction, for example, all play a part in the distribution of life.
Many factors affect natural selection which is the basis for evolution.
Environmental change including plate tectonics, sea level and perhaps catastrophic events, which change competition relationships and isolate species often leaving habitat niches available for opportunistic species to expand into. Time Travel 6 Examine figs on pages 24A, 24B, 27A and B in Course Reader Examine Ch. 11, pp. Large continental landmasses develop when smaller microcontinents come together along a convergent margin, and are sutured together. As a result, smaller landmasses that formed at different times come together to form one large landmass. Accompanying the orogenic events are widespread metamorphic events and pluton emplacement that resets the isotopic clocks.