Succession Flashcards
What is succession?
The process by which an ecosystem changes over time. The biotic conditions (e.g plant and animal communities) change as the abiotic conditions (e.g water availability) change. There are two types of successions
What is primary succession?
This happens on land that’s been newly formed or exposed e.g a volcano has erupted forming a new surface of rock. There is no soil or organic matter to start with, e.g just bare rock
What is secondary succession?
This happens on land that’s been cleared of all plants, but where the soil remains e.g after a forest fire where a forest has been cut down by humans
What is deflected succession? Give some examples
- When the natural cause of succession is interrupted/ deflected
- if this occurs the climax community is called a plagioclimax
- humans through controlled burning, mowing or grazing live stock, so the resulting climax community will differ from the natural community
What is a pioneer species?
- the first species to occupy a new habitat, starting new communities
- have rapid reproductive strategies enabling them to quickly occupy an uninhabited area
- many have asexual stage to reproduction
What is a climax community species?
-stable community that is reached, beyond which no further succession occurs
What are the characteristics of a pioneer species?
- can tolerate extreme conditions
- early arrivals
- have good means of dispersal, usually by wind
- are not able to compete for resources e.g light
- are not influenced or dependent on animal species
- may be able to fix nitrogen
What are the characteristics of a climax community species?
- strongly influenced by other organisms e.g competitors
- species found in the end point community
- have large seeds so seedlings can survive low light intensity
- have a specialised niche
- unable to tolerate great fluctuations in the water content of soil
