Research Methods Flashcards

1
Q

What is a hypothesis?

A

An educated guess as to what will happen during an experiment

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2
Q

What is a null hypothesis?

A

A hypothesis that states there will be no change during an experiment (no statistical relationship)

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3
Q

What is random sampling?

A

A subsample is chosen randomly from a larger set (e.g. random number generator)

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4
Q

What is the importance of random sampling?

A

Avoids bias

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5
Q

What is systematic sampling?

A

A subsample is chosen from a larger set with a fixed periodic interval (e.g access points along a river)

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6
Q

What is the importance of systematic sampling?

A

Regular sample intervals

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7
Q

What are the 2 types of transect?

A
  • Line transect
  • Belt transect
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8
Q

Where are transects applied?

A

To environmental gradients

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9
Q

Why is sample timing important?

A

To ensure variability is detected

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10
Q

What is sample size dependent on?

A

Homogeneity

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11
Q

What is sample number dependent on?

A

Variability

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12
Q

Why is standardisation important?

A

To allow comparisons between different experiments and ensure consistent reliability

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13
Q

What are the 3 types of quadrat?

A
  • Frame
  • Grid
  • Point
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14
Q

What do the 3 types of quadrat measure?

A
  • Frame - percentage frequency
  • Grid - percentage cover
  • Point - local frequency
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15
Q

What are the limitations of quadrats?

A
  • Subjective observations
  • Plants may be flattened
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16
Q

What are kick sampling and surber sampling used for?

A

Sampling of freshwater invertebrate species

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17
Q

How does kick sampling work?

A
  1. Net held downstream in a river
  2. Agitation through kicking
  3. Invertebrates are caught in the net
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18
Q

What are the limitations of kick sampling?

A
  • Organisms may swim away
  • Difficult to standardise
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19
Q

How does surber sampling work?

A
  1. Net attached to a frame is held downstream in a river
  2. Agitation in the frame using a trowel or a stick
  3. Invertebrates are caught in the net
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20
Q

What are the limitations of surber sampling?

A
  • Difficult on uneven river beds
  • Water flow must be fast
21
Q

How can kick sampling and surber sampling be standardised?

A
  • Same amount of kicks
  • Same sized net
22
Q

What is colonisation media?

A

Providing a suitable habitat which is attractive to species that an individual wants to monitor (e.g. beetle banks)

23
Q

What are the limitations of colonisation media?

A
  • Habitat may not be colonised
  • Affects true population size
24
Q

What is a pitfall trap used for?

A

Sampling of small terrestrial species (e.g. insects)

25
How does a pitfall trap work?
A small container is placed in the ground level to the surface and covered before being left for a period of time
26
What are the limitations of a pitfall trap?
- More mobile organisms are caught - Possible predation in the trap
27
How can a pitfall trap be standardised?
- Same sized container - Same preservation fluid - Same period of time it is left for
28
What is a sweep net used for?
Sampling of invertebrates in ground vegetation
29
How does a sweep net work?
A net is swept in a figure of eight configuration and repeated
30
What are the limitations of a sweep net?
- Flying organisms may escape - Some organisms may be harmed
31
How can a sweep net be standardised?
- Same number of sweeps - Same sweep length
32
What is a beating tray used for?
Sampling of invertebrates in tall vegetation
33
How does a beating tray work?
Vegetation is shaken and anything that falls out is collected in a tray
34
What are the limitations of a beating tray?
- Difficult to standardise - Flying organisms may escape
35
What is a light trap used for?
Sampling of night-flying insects (e.g. moths)
36
How does a light trap work?
Flying insects are attracted to the UV light and are trapped, allowing for counting and identification the next day
37
What are the limitations of a light trap?
- No moths will be present if it rains - Different insects are attracted to different wavelengths of light
38
What is a tullgren funnel used for?
Sampling of mobile invertebrates in leaf litter or soil
39
How does a tullgren funnel work?
A sample is placed on mesh beneath a light which causes organisms to move downward away from the light and through the mesh into a funnel and collection pot
40
What are the limitations of a tullgren funnel?
- Only species repelled by heat or light will be collected - Only small organisms fit through the mesh
41
What is earthworm extraction used for?
Sampling of earthworms in soil
42
How does earthworm extraction work?
Irritant is added to the soil to force earthworms to the surface for counting and identification
43
What are the limitations of earthworm extraction?
- Earthworms may move deeper - Earthworms may die
44
What is the most common abundance scale?
DAFOR
45
What does DAFOR stand for?
Dominant Abundant Frequent Occasional Rare
46
What is species frequency?
A measure of the dispersal of a species by recording the proportion of samples in which they were found
47
What does the Lincoln Index calculate?
An estimate of species' population size (capture, re-capture)
48
What are the limitations of the Lincoln Index?
- Assumes no population change - Assumes marked individuals mix freely with the rest of the population
49
What does Simpson's Index of Biodiversity calculate?
Biodiversity of an area