Organisation Of An Ecosystem

Question 1

What is a quadrat?

Answer 1

A square frame of known area used for sampling the abundance and distribution of slow or non-moving organisms.

Question 2

Why is it important to estimate the number of organisms in a population?

Answer 2

To better understand the relationships in a community

This information helpful to monitor conservation projects that aim to conserve endangered species or habitats

Question 3

What is sampling?

Answer 3

The selection of subjects included in a study

Question 4

When looking at plants in a quadrat what sampling can be used?

Answer 4

• number of individual species:
  The total number of individuals of one species (e.g. daises) is recorded
• species richness:
  The number of different plant or animal species is recorded but not the number of individuals within a species
  Percentage cover:
  Percentage of the quadrat area covers by one species (e.g. grass)

Question 5

What is a transect?

Answer 5

A line created with a tape measure along which sampling occurs

Question 6

What are quadrats used for?

Answer 6

Estimating population sizes

Used to measure the abundance and distribution of organisms in an area

Question 7

What can transects be used to investigate?

Answer 7

The effect of a factor on the distribution of a species

Question 8

What do food chains show?

Answer 8

Show the feeding relationship of different organisms and the flow of energy between the organisms

Question 9

Define biomass

Answer 9

The total mass of living material

Question 10

What are trophic levels?

Answer 10

The stages in food chain

Question 11

What is biomass used for in animals?

Answer 11

For respiration to release energy

Question 12

What is the equation to work out biomass efficiency?

Answer 12

Efficiency = gain in biomass
———————
Total biomass intake

Question 13

Describe the water cycle

Answer 13

Water from lakes and oceans evaporates
The water condenses in clouds and returns to earth as precipitation
The precipitation is useful for life on land
The water then returns to rivers and oceans through surface runoff

Question 14

Describe the carbon cycle

Answer 14

Plants absorb carbon dioxide during photosynthesis
The carbon molecules are passed to other organisms when eaten
Carbon dioxide is then released back into the atmosphere during respiration (from animals and plants)
Burin if fossil fuels also releases carbon dioxide into the atmosphere

Question 15

How do decomposers break down dead matter?

Answer 15

Release enzymes which catalyze the break down of dead material into smaller molecules