The total weight of all organisms in an ecosystem is called the

What do environmental scientists use to show a simple pattern of energy flow from producer to a consumer through to a decomposer.

The two individuals of different species help each other

A long term relationship in which one animal is helped and the other is harmed

The entire span of conditions in which a species can survive is called the

Any conditions not suitable for the survival of an individual is that individual's

The aging of an area that has not previously been occupied is gradually invaded by life forms. When it begins there is no soil.

This type of species is one that can invade areas that have experienced Volcanoes, Land- slides, Glacial movement

All living things must work against other individuals to acquire the resources they need. This is called