Succession Flashcards
What is succession
The changes overtime in the species occupying an area
What are the stages in succession
Barren Land
Primary colonisers
Secondary colonisers
Tertiary colonisers
Scrubland
Climax community
What is barren land
Bare rock
What are primary colonisers
Pioneer species
Characteristics of a climax community
High biodiversity
Very stable community
Lots of ecological niches
Complex food webs
High biomass
What are characteristics of a pioneer species?
Can nitrogen fix
Extremophiles
Can photosynthesise
Produced high quantity of wind dispersed seeds
Asexual reproduction
Rapid seed germination
What happens as succession progresses overtime?
Abiotic environment is less hostile
So greater number and variety of habitats and niches
So increased biodiversity
so more complex food webs
leads to increased biomass
What is primary succession?
When area previously devoid of life is colonised by communities of organisms
What is secondary succession and why does it allow succession to begin at a later stage?
Occurs in a previously colonised area in which an existing community has
been cleared e.g forest fire
Soil layer will already be present
How does succession occur?
Colonisation occurs from a pioneer species
Pioneer species cause a change in the environment ( soil formation, greater nutrient abundancy)
Environment becomes less hostile for other species
This allows an increase in biodiversity and biomass
Eventually progresses to form a climax community
What are the effects of succession?
Abiotic environment becomes less hostile
Greater variety and number of habitats and niches
Increased biodiversity
Complex food webs arise
Increased biomass
Is primary or secondary succession faster and why?
Secondary
Soil already exists and some spores and seeds remain in the soil
