Explain and illustrate how the long-term survival of a species depends on resources that may be limited from time to time?

Answer 1

Even if a number of individuals survive, the population size may become too small for the species to continue. Small populations may have breeding problems. They are susceptible to random environmental fluctuations and genetic drift to a greater degree than are larger populations. The chance of extinction increases exponentially with decreasing population size.

The MVP is the smallest population size that can avoid extinction by the two reasons listed above. If no severe environmental fluxes develop for a long enough time, a small population will recover. The MVP depends heavily on reproductive rates of the species.

The environment is the ultimate cause of population stabilization. Two categories of factors are commonly used: physical environment and biological environment. Three subdivisions of the biological environment (BIOTIC factors) are competition, predation, and symbiosis.

Physical environment (ABIOTIC) factors include FOOD, SHELTER, WATER supply, SPACE availability, and (for plants) SOIL and LIGHT. One of these factors may severely limit population size, even if the others are not as constrained. The LAW OF THE MINIMUM states that population growth is limited by the resource in the shortest supply.

The biological role played by a species in the environment is called a niche. Organisms/populations in competition have a NICHE OVERLAP of a scarce resource for which they compete. COMPETITIVE EXCLUSION occurs between two species when competition for resources is so intense that one species completely eliminates the second species from an area.

Population Decline and EXTINCTION

Extinction is the elimination of all individuals in a group. Local extinction is the loss of all individuals in a population. Species extinction occurs when all members of a species and its component populations go extinct. Scientists estimate that 99% of all species that ever existed are now extinct. The ultimate cause of decline and extinction is ENVIRONMENTAL CHANGE. Changes in one of the physical factors of the environment may cause the decline and extinction; likewise the fossil record indicates that some extinctions are caused by migration of a competitor.

Answer 2

When 2 species directly compete for a limited resource, only 1 will ultimately be sustained in that space. The other will die out