Ecology

Organism, population, community, ecosystem, and biosphere, in order of increasing scale and complexity.

A group of individuals of the same species living in the same area and capable of interbreeding.

All the populations of different species that live and interact in a particular area.

A community of organisms together with the abiotic (nonliving) factors of their environment, interacting as a system.

Exponential growth produces a J-shaped curve under unlimited resources; logistic growth produces an S-shaped curve that levels off at the carrying capacity.

The maximum population size that an environment can sustain indefinitely given available resources.