Sucession Flashcards
What does autogenic succession mean?
“Self-made”, caused by biological processes of the organisms themselves.
Define facilitation
When a community alters the conditions of an environment in a way that favours other species and not themselves.
What are the trends during autogenic succession?
Increase in species diversity, food web complexity, niche and habitat variety, stability.
What happens to productivity during succession?
Increases but may decrease as climax community matures.
What are the stages of primary succession?
- colonisation of barren grounds
- formation of soil through production of humus
- increase in soil depth, nutrient content and stability
Who are pioneer species?
Lichens (firm attachments using fine threads of fungal partner) and mosses(root like hairs get into crevices).
What’s the main characteristic of pioneer species?
They can survive in very unfavourable conditions.
Describe the action of pioneer species.
Slowly open up crevices which fill with dead bits of lichen and moss. Content of crevices decays into humus, which holds water and nutrients.
Describe the next stages of primary colonisation.
- more complex plants can grow in the pockets of soil
- they increase nitrogen content and stabilise the soil
- climax community will eventually be able to colonise
Define secondary succession.
Occurs on plant soil that has already been formed but which has been cleared of plant life.
What’s the difference between primary and secondary succession?
Primary succession involves the colonisation of barren grounds, secondary succession occurs in already formed nutrient rich soil
Define allogenic succession.
Means “Made by others”, the replacement of one community by another which is caused by forces outside the plant community.
Give an example of a cause for allogenic succession
Climate change: may alter abiotic factors meaning some communities cannot survive and are replaced by others.
Define degradative succession.
It is the sequence of detritivore organisms associated with the break down and decomposition of a dead animal or plant
What is another name for degradative succession?
Heterotrophic succession.
