Distribution of organisms

Question 1

Name some biotic factors

Answer 1

competition for resources(food), predators, disease, grazing, parasites

Question 2

Name abiotic factors

Answer 2

light intensity, temperature, pH, soil moisture

Question 3

Which abiotic factor will affect the number of plants growing in a shady area and why

Answer 3

light intensity, plants need light for photosynthesis for growth

Question 4

What effect will competition have on biodiversity

Answer 4

other species will die out decreasing biodiversity

Question 5

What is used to measure light intensity

Answer 5

light meter

Question 6

What is the source o error and how do you minimise them for a light meter

Answer 6

a person shades meter- make sre nobody shades the meter
sensor not facing the light source- ensure sensor si facing light source

Question 7

What is used to measure moisture?

Answer 7

moisture meter

Question 8

what are the sources of error when measing moisture and how do you minimise them

Answer 8

probe wet from previous reading- dry probe between reading
reading taken at different depths- insert probe to same depth

Question 9

What are quadrats used for

Answer 9

to sample for abundance of plants in an ecosystem

Question 10

What are the sources of error when using a quadrat and how do you minimise them

Answer 10

insufficient number of samples- take more samples
avoid choosing good looking areas to sample- sample at random
do you include plants partly in or out of the quadrat- a plant should only be counted if more than half of it is within the quadrat

Question 11

What is a transect line?

Answer 11

uses a series of quadrats placed at specific points along the line to investigate a pattern in the distribution of organsims

Question 12

What is a pitfall trap?

Answer 12

are used to sample animals in an ecosystem

Question 13

What are the sources of error when using pitfall traps and how are they minimised

Answer 13

Animals do not fall into the trap- ensure trap is level with the ground
the number and types of animals may not be representative of the ecosystem as a whole- use more traps
birds may eat trapped animals- use a cover supported by stones

Question 14

What is the most common source of air pollution

Answer 14

combustion of fossil fuels

Question 15

What are indicator species?

Answer 15

Species that by their presence or absence indicate the level of pollution

Question 16

Name the apparatus which could be used to measure the rate of respiration in an earthworm and describe its use

Answer 16

Respirometer
Set up a container with earthworm
Add a chemical to absorb carbon dioxide
Measure the volume of oxygen consumed in a period of time