2.5

Question 1

Primary Succession

Answer 1

Occurs on bare rock with no soil (e.g., lava flows, retreating glaciers). Life starts from scratch.

Question 2

Secondary Succession

Answer 2

Happens after a disturbance (e.g., fire, floods, logging) but soil remains, allowing faster recovery.

Question 3

Which is Faster? Primary or Secondary succsession

Answer 3

Secondary succession is faster because soil and seeds remain, unlike primary succession, which starts from bare rock.

Question 4

Causes of Succession

Answer 4

Driven by biotic and climatic factors like wind, fire, soil erosion, and natural disasters

Question 5

Pioneer Species

Answer 5

First species to colonize, starting a simple ecosystem. Examples: Lichens, bacteria, plankton, fungi.

Question 6

Climax Species

Answer 6

Species that dominate in a stable ecosystem. Example: White spruce (Picea glauca) in northern forests.

Question 7

Climax Community

Answer 7

A stable ecosystem with multiple possible states, not just dense forests. Stability depends on climate, soil, and random events.

Question 8

Climax Community features

Answer 8

Greater biomass & species diversity
More complex food webs (increased stability)
Deeper soil & taller plants
Steady-state equilibrium (input ≈ output)

Question 9

Plagioclimax

Answer 9

When human activities alter natural succession, leading to a different stable state.

Question 10

Causes and impact of plagioclimax

Answer 10

Causes:
Trampling (e.g., footpaths compacting soil)
Burning (e.g., controlled fires for agriculture)
Agriculture (e.g., crop planting prevents forest regrowth)
Grazing (e.g., livestock eating young plants)
Resource Extraction (e.g., deforestation halts succession)

Impact:
➡ The resilience of the ecosystem determines how much it can recover.

Question 11

Succession

Answer 11

gradual process of change in an ecosystem over time, where new species replace older ones until a stable community forms.