Topic 7C - Populations And Ecosystems

Question 1

What is an ecosystem?

Answer 1

All the organisms living in a community aswell as all the abiotic conditions in the area which they live

Question 2

What are biotic conditions of an ecosystem?

Answer 2

Living features of an ecosystem. E.g. the presence of predators or food

Question 3

What are abiotic conditions of an ecosystem?

Answer 3

The non living features. E.g. the temperature or soil

Question 4

What is a habitat?

Answer 4

The place where an organism lives

Question 5

What is a niche?

Answer 5

The role of a species in a habitat

Question 6

What is an adaptation?

Answer 6

Feature that members of a society have that increases their chances of survival

Question 7

What’s is a population ?

Answer 7

All the organisms of one species in a habitat

Question 8

What is a community?

Answer 8

Population of different species in a habitat

Question 9

What is the carrying capacity?

Answer 9

The maximum stable population size of a species that an ecosystem can support

Question 10

What are 3 biotic factors ?

Answer 10

Interspecific competition
Intraspecific competition
Predation

Question 11

What is abundance?

Answer 11

Number of individuals of one species in a particular area

Question 12

What is distribution?

Answer 12

Where a particular species is within the area you are investigating

Question 13

Give a brief method for random sampling? (5)

Answer 13

1. Choose an area to sample
2. Ensure sample is random to avoid bias - use random number generator
3. Use appropriate technique to take a sample of the population
4. Repeat and take as many samples as possible
5. Conclude results and work out the mean aswell as percentage cover

Question 14

What is a running mean? What is the purpose of a running mean?

Answer 14

• Where you work out the mean of all the data each time you collect a new sample
• once the mean no longer changes your should have data that gives a REALISTIC ESTIMATE FOR THE WHOLE AREA

Question 15

What are transects?

Answer 15

Lines to help find out how organisms are distributed across an area

Question 16

What are the 2 types of transects?

Answer 16

Belt transects
Interrupted belt transects

Question 17

What are belt transects?

Answer 17

Quadrats are placed next to each other along the transect to work out species frequency and percentage cover along the transect

Question 18

What is interrupted belt transects?

Answer 18

Placing quadrat at regular intervals instead of measuring the whole transect

Question 19

What is ‘mark-release-recapture’ method? (6)

Answer 19

1. Capture a sample of species using an appropriate technique
2. Mark them in harmless way
3. Release them back into their habitat
4. Wait a week, then take a second sample from same population
5. Count how many of the second sample are marked
6. To estimate total population size = number of 1st sample size x number of 2nd sample / number of 2nd sample marked

Question 20

What is succession?

Answer 20

The process by which an ecosystem changes over time. Happens in a series of stages

Question 21

What is a pioneer species?

Answer 21

The first species to colonise the area

Question 22

How do pioneer species change abiotic conditions?

Answer 22

Die and microorganisms decompose the dead organic material, which forms a basic soil
This makes condition less hostile, so new organisms can grow there
Continues to happen and environment gets less and less hostile allowing a wider range of species being able to grow in it

Question 23

What occurs during the later stages of succession?

Answer 23

Ecosystem becomes more complex, eventually leading to a climax community

Question 24

What is secondary succession?

Answer 24

Happens on land that’s been cleared of all plants but where the soil remains
Similar to primary succession but the new pioneer species are usually larger plants

Question 25

What is plagioclimax?

Answer 25

When succession is stopped articifically (due to humans)

Question 26

What is conservation?

Answer 26

Protection and management of species and habitats in a sustainable way

Question 27

What are the 5 conservation methods?

Answer 27

Management of succession
Seed banks
Captive breeding
Fishing quotas
Protected areas