Chapter 14 INTERACTIONS in Ecosystems


The cows live closely with the grass and the both befit from each other

Three Types

mutualism, where both species benefit (Cows and grass) commensalism, where one species benefits and the other is unaffected(Eyebrow mites and human) parasitism, where one species benefits and the other is harmed.(Catipiller and wasp larva)


For humans, population density is the number of people per unit of area, usually quoted per square kilometer or square mile.Commonly this may be calculated for a county, city, country, another territory, or the entire world.

Population dispersion is the observation of where individuals are found in a habitat. How individuals "disperse" themselves. There are three main types of dispersion: clumped, uniform and random. Examples Cumped-Cows, Uniform-Birds, and Random-Humans


Population size

Birth rate

Death rate



Population size is the actual number of individuals in a population. Population density is a measurement of population size per unit area, i.e., population size divided by total land area. Abundance refers to the relative representation of a species in a particular ecosystem.

The four factors that can affect population size are fertility rate, mortality rate, immigration and emigration.The fertility rate of a population refers to the average amount of children that women have throughout their lifetime, adjusted to births per certain amount of the population in the year. The opposing factor to fertility rate is mortality rate, which is equal to the typical amount of deaths per the same amount of the population in the year. Finally, immigration is a count of how many foreigners become residents of the country, while emigration is a count of how many residents leave the country.


Created with images by Gugelmim - "flowers bugs nature" • boettcherguilherme - "Symbiosis" • FrankWinkler - "country house building home" • jans canon - "gulls in a row" • pcdazero - "herd cow pasture" • kangheungbo - "baby twins 100 days photo" • havankevin - "Rafaels restingplace" • Britt Selvitelle - "Immigration Reform Rally" • greger.ravik - "Airplane"

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