Chapter 6: Change in ecosystems

Question 1

What is succession?

Answer 1

The process of change on community composition and structure, towards the establishment of a stable ecosystem.

Question 2

What are the 3 steps of succesion?

Answer 2

1. Primary succession
2. Secondary succession
3. Climax community

Question 3

What occurs in primary succession?

Answer 3

Occurs after catastrophic events that leave barren sites with no organisms.
- Pioneer plants colonise
- Soil formation
- R-selected species increase population rapidly
- New communities form
- Succession slowly continues and biodiversity increases

Question 4

What occurs in secondary succession?

Answer 4

Occurs when there is a change in an ecosystem, and there was a previous community there before. When there is a natural disturbance (fire or flood) or human intervention (deforestation)
- Natural disturbance occurs
- R-selected plants colonise area, invertebrates enter ecosystem
- Slower growing trees grow and stabalise community, herbivores, carnivores and omnivores join food web
- New community is formed an eventually becomes a climax community

Question 5

What is a climax community?

Answer 5

The stable community present at the final stage of succession.
It is stable as long as environmental factors remain unchanged

Question 6

What are 2 advantages of prescribed burning?

Answer 6

• Removes dominant plant species and opens up space for other living thngs
• Smoke can promote germination