Succession

Question 1

🔴️Climax community

Answer 1

Stable community so no further succession occurs

Question 2

🔴️Succession

Answer 2

• Change in community over time
• caused by a change in abiotic factor
• or due to a species being present

Question 3

Describe and explain the process of succession

Answer 3

1. Population of Pioneer species colonises, grows, dies and forms humus
2. They change the environment by adding nutrients e.g nitrates, making it less hostile;
3. The change in conditions allows new SPECIES to colonise and survive
4. These are better competitors so the pioneer species are outcompeted
5. The new species increases in population but the pioneer species decreases
6. The biodiversity changes
7. The environment is more stable its more hospitable
8. This occurs until the climax community is reached

Question 4

How can conservation be used to prevent succession?

Answer 4

• used to prevent formation of woody forests
• involves: deforestation and using herbicides

Question 5

Conservation

Answer 5

• Management of our environment to maintain species diversity

Question 6

Problems with deforestation

Answer 6

Soil

• Trees normally protect soil from rain
• exposure of soil may lead to erosion
• Less habitats and variety of food, leading to reduced biodiversity

CO2

• Less CO2 taken in as less photosynthesis occurs
• Combustion of trees releases CO2;
• Saprobiotic microorganisms decompose trees, and respire, releasing CO2
• Greenhouse effect may lead to changed rainfall patterns

Question 7

How trees can be used as a sink

Answer 7

• Absorb extra carbon dioxide during photosynthesis;
• Carbon used in forming permanent biomass
• Carbon is incorporated in organic molecules e.g starch

Question 8

Suggest advantages of vegetative propagation (reproduction) of clover

Answer 8

• Rapid process;
• Large number produced from only one plant

Question 9

How exactly do pioner species (plant) increase the soil nitrate concentration?

Answer 9

• Plants die, and saprobiotic microorganisms decompose them, forming humus
• Pioneer species can be leguminous so nitrogen fixation occurs
• Leading to increase in nitrification, so more ammonia to nitrate by nitrifying bacteria;

Question 10

Explain what limits the size of populations in a climax community

Answer 10

Plants

• availability of nutrients e.g nitrates ;
• numbers of producers providing energy for a food chain
• limiting factors e.g light intensity affecting the rate of photosynthesis;

Animals

• disease may kill weaker members of species;
• size of niches;
• balance between rate of reproduction and death rate;
• intra and interspecific competition for resources e.g water
• predator size may increase leading to more predation

Question 11

When measuring succession across a place, why lay the quadrat at regular intervals

Answer 11

• Systematic sampling used
• To establish pattern and trends

Question 12

Reasons to conserve woodlands

Answer 12

• Protects habitats
• Source of medicines
• More Tourism so economic benefits

Question 13

3 features of a climax community

Answer 13

1. abiotic factors constant
2. populations are stable
3. same species present over time (stable community)