Ecosystems

What is an Ecosystem? Ecosystem – A community of organisms in a given area and the abiotic/biotic factors that affect them.

Abiotic vs. Biotic Factors Abiotic – All the nonliving factors in an area. Examples: water availability, amount of sunlight, temperature, precipitation, etc. Also includes Nutrient Cycles Biotic – All the living and once living factors in an area. Examples: plants, animals, bacteria.

List the abiotic and biotic factors in the picture:

Habitat and Niche Habitat – A place where animals and plants naturally live and grow. Niche – A habitat that supplies the factors necessary for existence. Also, the ecological role of an organism in its community.

Populations in Ecosystems Population – A group of organisms belonging to the same species that live in a particular area. What kinds of things influence a Population? What makes Population Numbers increase? What makes Population Numbers decrease?

Population Factors Density-Dependent Factors – Factors triggered by overpopulation or overcrowding. Examples: Competition (food, water, shelter) Predation, Parasitism, and Disease. Density-Independent Factors – Factors that occur regardless of the Population. Examples: Weather or climate change, Natural disasters, and Human activities (pollution)

Population Simulation Watch the Simulation and observe how the bunny population changes when Biotic and Abiotic Factors are introduced. http://phet.colorado.edu/en/simulation/natural-selection

Population Simulation What does the bunny population need to live and grow? What biotic factors change the bunny population? What abiotic factors change the bunny population? Why does color of the bunnies make them more successful (wolves don’t eat them) in the one location or the other?