ecological successions

Question 1

what is meant by succession ?

Answer 1

• the change in an ecological community over time

Question 2

what does a primary succession start with ?

Answer 2

• starts with a pioneer species colonising bare rock or sand

Question 3

why may bare rock be present first ?

Answer 3

• due to new land being created
• or due to a volcanic eruption

Question 4

what is meant by a pioneer species ?

Answer 4

• it is the first species to colonise the bare rock

Question 5

example of a pioneer species ?

Answer 5

• lichen

Question 6

what are pioneer species adapted to do ?

Answer 6

• they are adapted to survive in harsh abiotic factors

Question 7

through the lichen’s death and decomposition what can they do ?

Answer 7

• they can change their abiotic factors to become less harsh and form a thin layer of soil (humus)

Question 8

because the thin layer of soil is produced (humus), what does this allow to survive ?

Answer 8

• mosses and smaller plants can now survive

Question 9

what do the creation of mosses and smaller plants do to the soil ?

Answer 9

• they further increase the depth and nutrient content of the soil

Question 10

As the pattern continues,what does this do to the abiotic factors around the previously bare rock ?

Answer 10

• the abiotic factors continue to become less harsh
• larger plants can survive and change the environment further

Question 11

what can each new species do to the environment and what does this cause ?

Answer 11

• they change the environment in such a way that it becomes less suitable for the previous species

Question 12

what happens to the previous species on the bare rock ?

Answer 12

• each species becomes outcompeted by a new species colonising

Question 13

what can the changes that that organisms produce in their abiotic environment result in ?

Answer 13

• less hostile environment
• abiotic factors are much more favourable
• increase in biodiversity

Question 14

what is the final stage in succession known as ?

Answer 14

• the climax community

Question 15

what is the climax community dominated by ?

Answer 15

• by trees

Question 16

what is meant by secondary succession ?

Answer 16

• when a community at its climax or previous stage is disrupted and plants are destroyed

Question 17

what are examples of disruptions ?

Answer 17

• natural disasters
• deforestation
• overgrazing by animals

Question 18

how is secondary succession different to primary succession ?

Answer 18

• the soil is already created in secondary succession
• so you do not start with bare rock seral stage

Question 19

what is the result of succession ? (5)

Answer 19

• species richness increases
• number of organisms increases
• biodiversity increases
• as succession occurs, larger plant species and animals start to colonise the area
• food webs become more complex

Question 20

how do you prevent succession from progressing ?

Answer 20

• through conservation of habitats

Question 21

what does the destruction of habitats, ususally by humans, result in ?

Answer 21

• loss of food and space for organisms and can lead to extinction

Question 22

what do we do to conserve habitats ?

Answer 22

• succession is often managed

Question 23

why do humans destroy habitats ?

Answer 23

• as human population grows
• there is a need for land for agriculture and for housing
• timber found in forests can be coppiced for fuel and furniture

Question 24

when discussing conservation, what does there have to be a compromise between ?

Answer 24

• human needs and conservation

Question 25

what is 1 strategy for conservation of habitats to manage successions ?

Answer 25

- by maintaining earlier staged of succession and preventing a climax community - greater variety of habitats are conserved - therefore greater range of species