ecological succession succession is a result of changing conditions in an ecosystem

Ecological Succession

Succession is a result of changing conditions in an ecosystem.

Succession regenerates or creates a new community.

• a sequence of biotic changes

• damaged communities are regenerated

• new communities arise in previously uninhabited areas

2 types of succession: Primary and Secondary

• primary succession — started by pioneer species, such as lichens and mosses

• occurs in previously uninhabited area

• example: when bare rock is exposed by receding glacier

Secondary succession is started by remaining species

• occurs after fires or natural disasters

Primary or Secondary?• Early settlers cleared forests and

replanted with crops.• An abandoned parking lot cracks and

weeds begin to grow.• A volcano erupts, but within years plants

begin to inhabit the barren lava.• A farmer stops growing crops in a field and

lets it return to nature. • Sand dunes develop due to wind. Soon

pioneer species begin living on the dunes.

A small group of people are stranded on a barren desert island.

They have 500 bushels of wheat and one cow. What should they do to survive for the greatest length of

time?

A small group of people are stranded on a barren desert island. They have 500 bushels of wheat and one cow. What

should they do to survive for the greatest length of time?

A. Eat the wheat and then eat the cow

B. Eat the cow and then eat the wheat

C. Feed the wheat to the cow, drink the milk, and then eat the cow.

Only ___ % of the energy from one trophic level passes to the next.

What happens to the remaining 90%?

It is used by the organisms or converted to heat

A small group of people are stranded on a barren desert island. They have 500 bushels of wheat and one cow. What

should they do to survive for the greatest length of time?

A. Eat the wheat and then eat the cow

B. Eat the cow and then eat the wheat

C. Feed the wheat to the cow, drink the milk, and then eat the cow.