Limiting Factors Page 77

Levels of Organization Biosphere – the collection of all the ecosystems on the planet Ecosystem – an area made up of all living organisms, as well as the climate, soil, water, rocks, and other non-living things Community – a group of different species that live together in one area Population – a group of the same species that lives in one area Organism – one individual living thing

Sizes of Populations The size of a population is constantly changing for one of any of the following reasons: Births – an increase in the number of individuals in a population Deaths – a decrease in the number of individuals in a population Immigration – the movement of individuals into a population from another population Emigration – the movement of individuals out of a population and into another population

How much can an ecosystem hold? Carrying capacity – the maximum number of individuals of a particular species that the environment can support Why can an environment only support so many individuals? Food Water Space Mates Predators Parasites Disease These are called limiting factors.

Types of Limiting Factors Density-dependent limiting factor Density-independent limiting factor Competition Unusual weather Predation Natural disasters Parasitism Human activities Disease Density-dependent limiting factor – factors affected by the number of individuals living in a given area Density-independent limiting factor – factors that affect the size of the population, no matter what density of individuals live in an area.