Ecosystems essays

Ecosystems essays Ecosystems: Populations and Succession- in May and June of 1988, after an extended drought, Yellowstone National Park was covered with a large number of fire because of lightning. Although the fires were devastating, nature had started its process of vegetation all over again within two weeks. As time progressed, so did vegetation. I. Populations Dynamics- each species in an ecosystem exists as a population * population equilibrium- a state of balance between births and deaths in a population A. Population Growth Curves- when the size of a population is plotted over time. Two basic kinds of curve can be seen: s-curves and j-curves. B. Biotic Potential versus Environmental Resistance- see definitions below * biotic potential- the inherent capacity of an organism or species to reproduce and survive * recruitment- the process of adding new individuals to a population or subpopulation (as of breeding individuals) by growth, reproduction, immigration, and stocking * reproductive strategies- to produce massive numbers of young, but then leave survival to the whims of nature is the first reproductive strategy, the second strategy is to have a much lower reproductive rate, but then care for and protect the young to enhance recruitment * exponential increase- the growth produced when a base population increases by a given percentages each year * population explosion- a pyramiding of numbers of a biological population; especially : the recent great increase in human numbers resulting from increased survival and exponential population growth * environmental resistance- the totality of factors such as adverse weather conditions, shortages of food or water, predators, and diseases that tend to cut back populations and keep them from growing or spreading * replacement level- the fertility rate that will just sustain a stable population * carrying capacity- the population (as of deer) that an area will support without unde...