Life on Earth - Distribution of Organisms and Sampling Techniques

Question 1

Abiotic factor

Answer 1

term used to refer to a factor that relates directly to a non-living feature of an ecosystem

Question 2

Biotic factor

definition

Answer 2

term used to refer to a factor that relates directly to some aspect of living organisms in an ecosystem

Question 3

Sampling techniques, their use, and how to set them up (include problems and solutions)

quadrat and pitfall traps

Answer 3

Quadrats:
- used for estimating the abundance of low lying plants or slow moving animals in an ecosystem
- an error that can occur is determining whether an individual organism is in a certain square or not
- the solution is to follow certain rules when using quadrats, for example if its on the line then it is in the quadrat
- they should be thrown multiple times randomly and an average should be taken for an accurate sample of the environment

Pitfall Trap:
- used to sample invertebrates which live on the ground
- dig a hole and put a plastic pot inside. make sure its level with the ground so the organisms can fall in. camouflage the trap and leave to collect results
- problems include water getting in when it rains, birds taking eating trapped animals, the animals eating each other in the trap
- the solution is to put small holes in the bottom for drainage, camouflage so birds don’t see trap and to check the trap often or add a preservative such as ethanol

Question 4

Indicator species

Answer 4

organisms whose presence or absence shows the state of an environments health or quality

Question 5

Abundance

Answer 5

measure to the extent to which an organism occurs in an ecosystem (such as rare, common etc.)

Question 6

Distribution

Answer 6

location or spread of a type of living organism in an ecosystem

Question 7

Line transect

Answer 7

method used to sample an ecosystem at intervals along a straight line using a sampling method