Why ecology matters

What limits the geographic distribution of organisms?

Populations cannot increase without limit

Favorable and unfavorable habitats exist for every species

Overexploited populations will collapse

Plant and animal communities can recover from disturbances

Communities can exist in several configurations

Keystone species may be essential to the functioning of biological communities

Natural systems are products of evolution

Natural systems recycle essential materials

Solar energy powers natural ecosystems

Climates change, communities and ecosystems change

Extinction is forever and species losses caused by humans are avoidable.