1. Elements of Ecosystems  Biotic Factors: The living organisms in an ecosystem  plants, animals, fungi, etc.  Abiotic Factors: The non-living portions of an ecosystem  Air, water, rocks, soil, etc.  Habitat: The physical location where an organism lives. A habitat supplies the organism with everything it needs to survive.

2. Example: habitat of a beaver:  Slow moving streams and rivers  Ponds and marshes  Must include woody vegetation (trees, shrubs)

3.  Community: All the organisms that live in the same place at the same time and interact with each other –A forest community would include trees, bushes, birds, squirrels, deer, mushrooms. Etc.

4. Population: All the organisms of the same species that live in the same place at the same time –Examples:  a population of deer in a forest  a population of pine trees in a forest

5.  Limiting Factor: Any biotic or abiotic factor that restricts the number of individuals in a population –Examples:  Water is a limiting factor in a desert  Sunlight is a limiting factor deep in the ocean  Other limiting factors: –Temperature (heat or cold) –Oxygen –Disease –Lack of soil