Paper 2: Topic 7 Ecology - Organisation of an ecosystem Flashcards Preview

Mrs P's GCSE Biology > Paper 2: Topic 7 Ecology - Organisation of an ecosystem > Flashcards

Flashcards in Paper 2: Topic 7 Ecology - Organisation of an ecosystem Deck (59)
Loading flashcards...
1

Define the term food web

  • A representation of the feeding relationships within the community
  • It shows the flow of energy and biomass between organisms

HINT: do not say it “shows who eats who”

2

Define the term food web

A series of interconnected food chains

3

Define the term producer

  • An organism at the start of a food chain
  • They have the ability to make glucose by photosynthesis using energy from the sun
  • E.g. plants, algae

4

Define the term trophic level

The feeding level of an organism within the food chain

5

Define the term biomass

The mass of the living material that makes up an organism

6

Define the term consumer

An organism that eat other organisms

7

Define the term herbivore

A primary consumer that feeds ONLY plants

8

Define the term carnivore

A consumer that feeds ONLY on animals

9

Define the term omnivore

A consumer that feeds on BOTH animals and plants

10

Define the term detritivore

An animal that feeds on dead animal, algal and plant material e.g. worms, beetles

11

Define the term predator

A consumer that hunts and kills another animal to obtain its food

12

Define the term prey

An organism that is hunted, killed and eaten by another animal

13

Describe the pattern between predators and prey in a stable community

  • In a stable community the numbers of predators and prey rise and fall in cycles.
  • The levels of both populations oscillates (fluctuates) in cycles

14

Describe the relationship between predators and prey in a stable community

  • The population of any species is determined by the availability of food
  • If the population size of the prey increases the population size of the predators will increase (a little time afterwards)
  • The increase in the population size of the predators will cause a decrease in the population size of the prey
  • If the population size of the prey decreases the population size of the predators will decrease (a little time afterwards)

15

State the term to describe a trend line that constantly fluctuates (goes up and down)

Oscillates

16

Explain why predator-prey cycles are always a little out of phase with each other

  • It takes a period of time for the population to respond to changes in the other population
  • E.g. it takes time for the foxes to reproduce if more rabbits become available

17

Place the following organisms in the correct sequence in a food chain:

Primary consumer

Producer

Tertiary consumer

Secondary consumer

Producer → Primary consumer → Secondary consumer → Tertiary consumer

18

Predator prey graph

19

Food chains

20

State the name of the piece of apparatus that s often used to study organisms in their habitats

Quadrat

21

State 2 methods that can be used to study organisms in their environment

  1. Quadrats
  2. Transects

22

Describe how to use a quadrat to study the distribution of small organisms

  1. Lie a 10m tape measure along the environmental gradient to be studied e.g. from the base of a tree out of the canopy
  2. Use a calculator to generate 10 random numbers
  3. Convert the random numbers to positions along the 10m tape measure e.g. 720 = 7m20
  4. Place the left hand corner of a 1m x 1m (1m2) quadrat at the first position on the tape measure
  5. Count all the organisms within the quadrat
  6. Repeat for each of the 10 positions
  7. Calculate the mean number of organisms per m2
  8. Repeat the above steps in the second sample site e.g. environment from a different species of tree
  9. Compare the two means (one from each sample site)

23

Describe how to calculate a mean

Remember: Maths will count for a minimum of 10% of the marks of each paper

Add all the data in the sample together then divide the total by the number of pieces of data 

24

Describe how to determine the mode

Remember: Maths will count for a minimum of 10% of the marks of each paper

Identify the number that appears the most frequently in the data set

 

25

Describe how to determine the median

Remember: Maths will count for a minimum of 10% of the marks of each paper

Arrange all the data in ascending order of size

Count the number of pieces of data

Divide the number of pieces of data by 2

Then count along the ascending order of numbers until you reach this point

 

26

State how the distribution of organisms across an area can be studied

Setting up a transect and using quadrats along the line

27

Describe how quadrats can be placed along a transect to prevent bias

  • Use random numbers to decide where to place the quadrat

OR

  • Place quadrats at specified intervals e.g. every 2m along the tape measure

28

Describe how to estimate the percentage cover of organisms in a quadrat

  • Use a grid quadrat (a frame divided into smaller squares)
  • Count the number of squares covered by the first organism
  • Convert this to a percentage:
    • (Number of squares covered by the organism divided by total number of squares ) multiplied by 100
  • Repeat for all other organisms

29

State 3 environmental changes that can affect the distribution of organisms

  1. Availability of water
  2. Temperature
  3. Composition of atmospheric gases (carbon dioxide, oxygen)

30

Explain how the availability of water can affect the distribution of organisms

The distribution of some animals e.g. wildebeasts, elephants, lions, camels varies in the wet and dry seasons

Decks in Mrs P's GCSE Biology Class (26):