1. 1.1 Biotic and Abiotic Factors in Ecosystems (sec 2.1 pg 21-24)

2. The study of how organisms interact with each other and with their physical environment is called ecology.

3. For practical reasons, ecologists divide the environment into different levels:

4. The environment is divided into different levels: Level 1: organism = single living thing.

5. The environment is divided into different levels: Level 2: population = all of the organisms of the same species that share a habitat.

6. The environment is divided into different levels: Level 3: community = all of the different populations in a particular area that interact.

7. The environment is divided into different levels: Level 4: ecosystem = includes the living community as well as the physical environment in which the organisms live

8. The environment is divided into different levels: Level 5: Biosphere = is the total area of Earth where living things are found.

10. Each environment has two kinds of factors: – Abiotic = non-living factors – Biotic = living factors ABIOTIC FACTORS BIOTIC FACTORS

11. A limiting factor is the most critical factor in determining the types of organisms that exist in an ecosystem. Many organisms compete for the same limiting factor(s).

12. Many ecosystems are in a state of dynamic equilibrium, where there is a balance between the abiotic and biotic factors and their connection to each other, but there is also continuous change. Most ecosystems experience continuous change, but the overall system is still stable.