10.1 succession

Question 1

what is primary succession?

Answer 1

this is the progressive colonisation of bare rock or barren terrain by living organisms.

Question 2

what is succession?

Answer 2

succession is the changing of an ecological community overtime

Question 3

what are the stages of primary succession?

Answer 3

1) Starts off with bare rock and no organism (empty inorganic surface)
this occurs because new land has been created due to volcanic eruption or landslide.
2)The first organism to live in that area is a pioneer species, which colonise the rock(break down) as they grow on it.
3) pioneer species are adapted to survive in harsh abiotic conditions
4) when they die and decomposition occurs they form a thin layer of soil called humus, this changes the abiotic factors to become less harsh because the soil retains some water and minerals allowing smaller plants to begin to grow .

Question 4

what is the second stage ?

Answer 4

5) more complex small plants begin to grow such as mosses and they further increase the depth ad nutrient content in the soil. reducing the harshness of abiotic factors further. now larger plants can survive and change the environment further.
6) each time a new species grows and changes the environment , they make it less suitable for the previous species. e.g when mosses and smaller plants began to grow, they covered the lichen so they couldn’t get any sunlight, so they where outcompeted by the new species colonising.
7) forests start to grow.
8) finally we are left with a climax community and the abiotic factors are much less hostile, so biodiversity increases.
climax community is dominated by trees

Question 5

what is a climax community?

Answer 5

all the organisms which make up the final stages of a ecological succession

Question 6

what is a secondary succession?

Answer 6

the recolonisation of an area after an earlier community was removed or destroyed

Question 7

what are the stages of a secondary succession ?

Answer 7

1) soil is already created so it does not start from bare rock. life is already present but has been altered in some way
usually faster than primary.
there are 3 main causes:
- natural catastrophe- fires, volcanic blast
- human destruction - burning forests, draining marshes.
- human management - ploughing, grazing.
2) successions occurs in the same way.l