7C Populations in ecosystems

Question 1

What is an ecosystem?

Answer 1

This is where all the organisms living in a community plus all the abiotic conditions as well

Question 2

What are biotic conditions

Answer 2

Living features of an ecosystem eg predators

Question 3

What are abiotic condition?

Answer 3

Non living features eg temp or soil

Question 4

What is the place an organism lives?

Answer 4

Habitat

Question 5

What is a niche?

Answer 5

This is the role of a species within a habitat eg what it eats, when and where it feeds

Question 6

What does the niche a specie occupy include

Answer 6

• Its biotic interactions : eg the organism it eats and those its eaten by
• Its abiotic interactions : eg the temp range an organism can live, the time of day it is active

Question 7

What will happen if 2 species try to occupy the same niche?

Answer 7

They will compete until one specie is left as one is more successful than the other

Question 8

What is an adaptation?

Answer 8

A feature that members of a species have that increases their chance of survival and reproduction

Question 9

What are the types of adaptations?

Answer 9

Physiological - processes inside their body
Anatomical - structural features
Behavioral - the way an organism acts

Question 10

What is a population?

Answer 10

A population is all the organisms of one species in a habitat

Question 11

What is a community?

Answer 11

populations of different species in a habitat make up a community

Question 12

What is population size

Answer 12

Total number of organisms of one species in a habitat

Question 13

What is the carrying capacity ?

Answer 13

Total number of organisms of one species in a habitat

Question 14

What is interspecific competiton?

Answer 14

Organisms of different species compete with eachother for the same resources.

If two species are competing but one is better adapted to the surroundings than the less well adapted species is likely to be outcompeted

Question 15

What is intraspecific competition?

Answer 15

Organisms for the same species compete with eachother for the same resources

If the population grows beyond the carrying capacity there wont be enough resources for all organisms and the population will decline, so there is less competition for space and food which is better for growth and reproduction so the pop can grow again

Question 16

What is predation?

Answer 16

Organisms kill and eats another organism

Population sizes of predator and prey are interlinked so as the pop of one changes the pop of another will change

Question 17

What is abundance

Answer 17

This is the number of individuals of one species in a particular area

Question 18

How do you measure abundance

Answer 18

• Frequency : the number of samples a species is recorded in
• Percentage cover : how much of the area you’re investigating is covered by a species

Question 19

How does random sampling work ?

Answer 19

1. Choose an area to sample
2. Should be random to avoid bias therefore use a random number generator
3. Use an appropriate technique eg quadrats and transects
4. Repeat so less results are due to chance
5. Take mean of all samples

Question 20

What is a running mean

Answer 20

Work out the mean of all the data each time you collect a new sample

Question 21

What are the methods for investigating populations

Answer 21

Quadrats
Transects

Question 22

How does quadrats work

Answer 22

It is a square frame divided into a grid of 100 smaller squares

1. Placed on the ground at different points
2. Measure species frequency or number of individuals of each species

Question 23

How does transects work and the different types

Answer 23

1. Belt Transects : quadrats placed next to eachother along transect to work out species frequency and percentage cover along transect
2. Interrupted Belt Transects : Instead of investigating the whole transect you can take measurements using a quadrat placed at regular intervals

Question 24

How do you capture motile organisms

Answer 24

• Net
• Pitfall trap

Question 25

What is Mark Release capture?

Answer 25

1. Capture a sample of species using an appropriate technique 2. Mark in a harmless way 3. Release back into habitat 4. Wait a week, and take a 2nd sample from same population 5. Count how many of second sample are marked

Question 26

How do you calculate Mark Release capture?

Answer 26

number caught in 1st sample x number caught in 2nd sample / number marked in 2nd sample

Question 27

How do you ensure Mark Release capture method is accurate ?

Answer 27

- The marked sample has enough time and opportunity to mix back in with the population - The marking hasnt affected the individuals chances of survival and is still visible -There are no changes in population size due to birth, migration and deaths

Question 28

What is succession

Answer 28

The process by which an ecosystem changes over time

Question 29

What is primary succession

Answer 29

1. Species colonise a new land surface 2. Seeds and Spores are blown in by the wind and begin to grow 3. First species to colonise area are called PIONEER SPECIES 4. Only pioneer species cope as they have adapted to cope with harsh conditions 5. The new organisms then die and are decomposed adding more organic material so the soil is richer in materials 6. Nitrogen fixing bacteria turn nitrogen from the atmosphere into ammonia forming ammonium ions so it can be used 7. Dominant species will out compete the plants and animals already there 8. Ecosystem becomes more complex as more species move in, plants create more habitats, abiotic conditions less hostile and biomass increases 9.Climax community

Question 30

What are some examples of hostile abiotic conditions

Answer 30

- Limited water available as theres no soil to retain water - Few minerals or nutrients as theres no soil - High Light intensity and fluctuating temperatures

Question 31

What is secondary succession

Answer 31

This happens on land that has been cleared of all the plants buy where the soil remains

Question 32

What is plagioclimax

Answer 32

This is where succession was stopped artificially

Question 33

What is a climatic climax community

Answer 33

Where the climax community is dependent on the climate in an ecosystem

Question 34

What is conservation

Answer 34

The protection and management of species and habitats in a sustainable way but as a dynamic process

Question 35

How is seed banks a conservation method?

Answer 35

They act as backup for the conservation of plant species

Question 36

How is captive breeding a conservation method?

Answer 36

- Breed Animals in controlled environments so they can then be reintroduced into the wild

Question 37

How is fishing quotas a conservation method?

Answer 37

Limit to the amount of fish species that fishermen are allowed to catch so less are killed

Question 38

How is protected areas a conservation method?

Answer 38

They restrict urban development, industrial development and farming