investigating populations and succession

Question 1

what is mark-release-recapture?

Answer 1

1)Animals in a specific area are ethically collected( usually by a netting or trap technique) and counted

2)The animals are then marked in some way that does not ability to feed or increase chance of predation( pant dots, UV)

3)the animals are then released and are left to redistribute into their population

4) After a reasonable time (hours, days or weeks depending on organism) a second capture is carried out and the total number caught is recorded, as well as how many out of those released and recaptured which were previously marked

Question 2

Describe random quadrating (4 marks)

Answer 2

1) use a grid/ split area into squares / sections
2) method of obtaining random coordinates eg: random number generator
3) place suitable amount of quadrats (20 quadrats)
4) count number of plants in quadrat
5) calculate mean average of section
number of quadrats x Area of section

Question 3

Name 3 common Abiotic factors

Answer 3

1) Temperature
2) Light intensity
3) pH

Question 4

Name 2 biotic factors

Answer 4

Competition between organisms, predations, disease, human impact, decomposers, paracites

Question 5

Describe intra and inter specific competition

Answer 5

1) intra - between members of the same species

2) inter - between members of different species

Question 6

succession occurs in natural ecosystems. Describe and explain how succession occurs ( 5 marks )

Answer 6

1) colonised by NAMED pioneer species ( the species that first colonize new habitats created by disturbance)
2) change in environment / example of change caused by organism present
3) enables other NAMED species to colonise/survive
4) change in diversity/biodiversity
5) stability (population numbers and biodiversity) increases / less hostile environment
6) climax community is presented by NAMED species

Question 7

What is an eco-system?

Answer 7

An eco-system is a community made up of living organisms and their interactions with non-living (abiotic) components such as air, water and mineral soil

Question 8

Why do no two species have exactly the same niche?

Answer 8

“Competitive exclusion principle” states that when two species compete for exactly the same resources, one is likely to out-compete the other and be more successful.

Question 9

What happens when niches overlap?

Answer 9

One species has adaptations that “outcompete” the other species, and eventually the second species is eliminated.

Question 10

Why is it incorrect to say that no two organisms have the same niche?

Answer 10

Different organisms may occupy the same ecological niche whilst competing until one species is eliminated

Question 11

When estimating what must be taken into consideration? (5)

Answer 11

• Data must be random to remove bias
• Data must be representative: large sample size enables statistical analysis
• Repeatable means reliable
• Running mean should show little change (concordant)
• Appropriate method used for that species