# Environmental Studies A2 ~ Practical Skills

### 17 terms by hannahmouse

#### Study  only

Flashcards Flashcards

Scatter Scatter

Scatter Scatter

## Create a new folder

### Hypothesis

the theory or explanation that is being investigated.
(states that a relationship exists)

### Independent Variable (IV)

the factor that is deliberately altered or measured to see if it affects the dependent factor

### Dependent Variable (DV)

the factor that may be controlled by the IV, i.e. the 'results' that are measured

### Null Hypothesis

the no-link theory against which the hypothesis is being tested.
(states that there is no relationship)

### Random sampling

the sampling sites within the study area can be chosen using a table of random numbers, or the random number function of a scientific calculator, to select coordinates on a grid

### Systematic sampling

this involves samples taken using a chosen pattern or spacing. (it can be considered to be random in that the samples are not chosen based on observable differences in the study area)

### Stratified sampling

if a study area has clear sub-areas with differences that will influence the results then it may be necessary to study each area individually, then combine the results

### Homogenous

evenly mixed

an area, usually square or circular, in which samples are taken

### Pitfall trap

a method of sampling animal populations by collecting individuals that fall into traps set into the ground

### Transect

a line or belt of sampling sites across an area

### DAFOR abundance scale

a qualitative scale that judges the abundance of organisms:
D = dominant
A = abundant
F = frequent
O = occasional
R = rare

### Lincoln index

a catch, mark, release, recapture method of estimating animal populations:
Total Population = No. in 1st sample x No. in 2nd sample / No. in 2nd sample that have marks

### Kick sampling

the riverbed is disturbed by kicking so that mobile invertebrates are washed into a net downstream

### Surber sampler

an aquatic invertebrate sampling frame and net that provides more quantitative data than kick sampling

### Pooter

a mouth-suction device to pick up invertebrates in soil or leaf litter

### Sweep Nets

lightweight newts with large diameter that can be swept through vegetation to collect invertebrates.
If number and length of the sweeps are standardized then semi-quantitative data can be collected.

Example: