Populations Science Bennett

Can any population of organisms keep growing forever? Changes in a population in one part of a food web affects populations in other parts of the web. The largest population of a species that an environment can support is called the carrying capacity. Species = a group of organisms that can interbreed and produce fertile offspring

What factors determine the carrying capacity? 1. Materials and Energy 2. Food Chains- populations are limited by their food supplies. 3. Competition- among individuals for resources – Intraspecific competition = competition among members of the same species. – Interspecific competition = competition between species.

4. Population Density = how many individuals can live in an area at one time – Density-dependent factors = factors that increase in significance as a population grows, ex. overcrowding, aggression – Density-independent factors = factors that can limit the population, regardless of size, ex. forest fire

Ecological Niche = the way that an organism occupies a position in an ecosystem including all the necessary biotic and abiotic factors. Predator = an organism that kills and consumes other organisms Prey = an organism that is eaten as food by a predator

Bottom-up population regulation = when the size of the prey population decreases causing a decrease in the predator population, due to the lack of food. Top-down population regulation = when the size of the predator population increases causing a decrease in the prey population. Eventually this results in a decrease in the number of predators.

Mutualism = a symbiotic relationship between two species in which both species benefit from the relationship. Parasite = an organism whose niche is dependent on a close association with a larger host organism.

Continue to “Monitoring Changes in Populations”