unit 7, succession Flashcards
what is succession?
change in ecological community over time
what is lichen and what does it do?
- they are made up of fungus and algae
- the fungus releases enzymes that break down rocks to release minerals
- the fungus acts like a sponge, holding water and nutrients
- the algae photosynthesises t make organic substances like glucose
- lichen makes conditions lss harsh as they are the pioneer species
what are the stages of primary succession?
1) the pioneer species (like lichen) colonise bare rock/sand where there are harsh conditions.
2) due to pioneer species making conditions less harsh mosses and smaller plants can now survive which further increases the nutrients and depths of the soil
3) this continues, each time the abiotic factors become less harsh, until larger plants can survive
4) each new species may change the environment so much that the previous species can no longer survive there and they become out competed
5) climax community is now reached , increase of biodiversity, and a less hostile environment
what is secondary succession?
this occurs when the primary succession land is destroyed and just soil left. it ALWAYS starts from soil, not bare rock/sand
causes for secondary succession?
-flood
-fire
- deforestation
what is the result of succession?
-larger plants/ animals species colonise area
- biodiversity increases
- food webs become more complex
what is coppicing and why is it beneficial?
- trees are not completely cut down, they are cut at the trunk, they are not pulled out of the ground
- this allows smaller plant species to grow due to the increase of light
- humans still gain resources for the humans growing population like timber for furniture
- allows tree to survive
how can you provide conservation of habitats?
-preventing/ managing succession
-preventing climax community means greater variety of species are conserved and a greater range of species, increase of biodiversity
