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A Level Environmental Science > Research Methods > Flashcards

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
Q

How does a pitfall trap work?

A

A small container is placed in the ground level to the surface and covered before being left for a period of time

26
Q

What are the limitations of a pitfall trap?

A
  • More mobile organisms are caught
  • Possible predation in the trap
27
Q

How can a pitfall trap be standardised?

A
  • Same sized container
  • Same preservation fluid
  • Same period of time it is left for
28
Q

What is a sweep net used for?

A

Sampling of invertebrates in ground vegetation

29
Q

How does a sweep net work?

A

A net is swept in a figure of eight configuration and repeated

30
Q

What are the limitations of a sweep net?

A
  • Flying organisms may escape
  • Some organisms may be harmed
31
Q

How can a sweep net be standardised?

A
  • Same number of sweeps
  • Same sweep length
32
Q

What is a beating tray used for?

A

Sampling of invertebrates in tall vegetation

33
Q

How does a beating tray work?

A

Vegetation is shaken and anything that falls out is collected in a tray

34
Q

What are the limitations of a beating tray?

A
  • Difficult to standardise
  • Flying organisms may escape
35
Q

What is a light trap used for?

A

Sampling of night-flying insects (e.g. moths)

36
Q

How does a light trap work?

A

Flying insects are attracted to the UV light and are trapped, allowing for counting and identification the next day

37
Q

What are the limitations of a light trap?

A
  • No moths will be present if it rains
  • Different insects are attracted to different wavelengths of light
38
Q

What is a tullgren funnel used for?

A

Sampling of mobile invertebrates in leaf litter or soil

39
Q

How does a tullgren funnel work?

A

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
Q

What are the limitations of a tullgren funnel?

A
  • Only species repelled by heat or light will be collected
  • Only small organisms fit through the mesh
41
Q

What is earthworm extraction used for?

A

Sampling of earthworms in soil

42
Q

How does earthworm extraction work?

A

Irritant is added to the soil to force earthworms to the surface for counting and identification

43
Q

What are the limitations of earthworm extraction?

A
  • Earthworms may move deeper
  • Earthworms may die
44
Q

What is the most common abundance scale?

A

DAFOR

45
Q

What does DAFOR stand for?

A

Dominant
Abundant
Frequent
Occasional
Rare

46
Q

What is species frequency?

A

A measure of the dispersal of a species by recording the proportion of samples in which they were found

47
Q

What does the Lincoln Index calculate?

A

An estimate of species’ population size (capture, re-capture)

48
Q

What are the limitations of the Lincoln Index?

A
  • Assumes no population change
  • Assumes marked individuals mix freely with the rest of the population
49
Q

What does Simpson’s Index of Biodiversity calculate?

A

Biodiversity of an area

A Level Environmental Science (17 decks)

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