Genetics, populations, evolution and ecosystems - Populations in Ecosystems

Question 1

What is the definition of ‘population’

Answer 1

Individuals of the same species occupying one area, at one tome, that can potentially interbreed

Question 2

What is the definition of ‘community’

Answer 2

All the populations of all the species in one area at on time

Question 3

What is the definition of ‘ecosystem’

Answer 3

An ecosystem consists of the community and the non-living components of its environment

Question 4

What is the definition of ‘niche’

Answer 4

The role an organism plays in the ecosystem and how it interacts with the biotic and abiotic factors

Question 5

What is the definition of ‘carrying capacity’

Answer 5

The maximum population size an ecosystem can support

Question 6

What is the definition of ‘biotic factor’

Answer 6

A living factor which affects the distribution of an organism

Question 7

Give some examples of biotic factors

Answer 7

• Competition between organisms
• Predation
• Prey
• Food
• Disease

Question 8

What is the definition of ‘abiotic factor’

Answer 8

A non-living factor which affects the distribution of an organism

Question 9

Give some examples of abiotic factors

Answer 9

• Temperature
• Light intensity
• Wind speed
• soil pH
• The water level in the soil
• Slope of the land

Question 10

Explain the advantage of two different species occupying different niches

Answer 10

It reduces interspecific competition between them

Question 11

Define interspecific competition

Answer 11

The competition between members of different species

Question 12

Define intraspecific competition

Answer 12

The competition between members of the same species

Question 13

Describe and explain the predator and prey graph

Answer 13

• Initially, there is an increase in the prey population
• More prey provides more food for predators
• So, after a delay, there is an increase in predator population
• Predators eat more prey, so the prey population decreases
• With less prey to eat, the predator population then decreases as they die due to starvation
• So then the prey population increases as fewer are being eaten, and the cycle starts again

Question 14

Explain why sampling should be carried out at random

Answer 14

To ensure the data collected is not biased

Question 15

Explain why a large sample should be used

Answer 15

To ensure the data collected is representative, reliable and suitable for statistical analysis

Question 16

Describe the steps of how you would estimate the number of trees in a woodland by random quadrat sampling.

Answer 16

1. Area is divided into a grid and co-ordinates assign

Question 17

Describe the steps of how you would carry out a transect to measure the change in % cover of barnacles down a seashore

Question 18

Describe the process of mark-release-recapture

Question 19

Describe the assumptions that are made when using the capture-release-recapture method

Question 20

Describe the steps of how succession establishes a climax community starting with a pioneer species

Question 21

Describe two features of a climax community

Question 22

Explain how the conservation of habitats will involve managing succession