1.1 Biotic and Abiotic Factors in Ecosystems

(sec 2.1 pg 21-24)

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

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

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

• The environment is divided into different levels:• Level 2: population = all of the organisms of the

same species that share a habitat.

• The environment is divided into different levels:• Level 3: community = all of the different

populations in a particular area that interact.

• 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

• The environment is divided into different levels:• Level 5: Biosphere = is the total area of Earth where

living things are found.

• Each environment has two kinds of factors:– Abiotic = non-living factors– Biotic = living factors

ABIOTIC FACTORS BIOTIC FACTORS

• 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).

• 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.