Research methods Flashcards
(112 cards)
1
Q
What is accuracy?
A
A measure of how close the recorded result is to the real value
2
Q
What is precision?
A
The intervals between the possible results, e.g. rulers measuring in mm is more precise than cm
3
Q
What is a representative sample?
A
A subsample that accurately reflects the complete data set
4
Q
What is a reliable method?
A
Provides consistent, accurate results
5
Q
What is an anomalous result?
A
A result that differs from other results with which it was expected to be
6
Q
What is a valid study?
A
Produces precise, accurate, reliable results upon which conclusions can be based
7
Q
What are some standard ecological techniques?
A
Quadrats, pond nets, kick sampling, surber sampling, plankton net, sweep nets, aerial insect nets, colonisation media, pitfall traps, beating trays, light traps, Tüllgren funnel, suction samplers, earthworm extraction from soil, soil flooding and soil pit extraction
8
Q
What does the Lincoln Index do?
A
Estimates the total population by catching a proportion of the population (capture-mark-release-recapture)
9
Q
What is the Lincoln Index formula?
A
Total population= number in 1st sample x number in 2nd sample over number in 2nd sample that have marks
10
Q
What does the Simpsons Index of Biodiversity do?
A
Assesses the variety and abundance of species in an area
11
Q
What is the Simpsons Index formula?
A
D = N(N-1) over n(n-1)
12
Q
What is the p value?
A
The significance level: the % confidence that the results were NOT produced by random chance
13
Q
What is the required p value within the scientific community?
A
0.05
14
Q
What statistical test compares the relationship between two variables?
A
Spearman’s Rank Correlation Coefficient
15
Q
What statistical tests compare the means of two data sets?
A
T test and Mann-Whitney U test
16
Q
What statistical test compares the frequencies of items or events?
A
Chi-squared
17
Q
When should the T test be used?
A
When comparing the means of two data sets, when the data is normally distributed and measured
18
Q
When should the Mann Whitney U test be used?
A
When comparing the means of two data sets that were calculated or counted
19
Q
What does a soil auger do?
A
Collect a sample of known cross-sectional area and depth
20
Q
How is soil temperature measured?
A
Using a soil thermometer: place into soil at standard depth and wait until it’s stable and read while in the soil
21
Q
What are the methods of determining soil texture?
A
Soil sieves and sedimentation
22
Q
What’s the first step in sedimentation of soil?
A
2mm sieve or hand removal of twigs and pebbles etc
23
Q
What happens during sedimentation?
A
A cylinder is filled with soil then topped with water, sealed and inverted to mix
24
Q
When is the depth of soil measured during sedimentation and why?
A
2 minutes (sand settles), 2 hours (silt settles) and 2 days (clay settles)
25
What is systematic samplng?
Sampling at chosen intervals
26
Why should more samples be collected?
Makes the results more representative
27
What are the different types of quadrats?
Open frame, grid and point
28
What are the limitations of quadrats?
Subjective judgement may be involved, the quadrat frame may flatten or move plants
29
How can pond nets be standardised?
Number of sweeps, length of sweep and person
30
What are the limitations of pond nets?
Mobile species may escape
31
What is kick-sampling used for?
Collecting invertebrates that live on riverbeds
32
How is kick-sampling standardised?
Controlling the number and intensity of kicks as well as the person doing them
33
What are the limitations of kick-sampling?
Accurate standardisation is difficult, not all organisms can be dislodged, some can swim, water flow rate is variable and fragile organisms may be harmed
34
What is surber sampling used for?
Collection of invertebrates from the riverbed (kick-sampling)
35
What is the method to Surber sampling?
A fixed area of riverbed is sampled within a box-like frame, the riverbed is disturbed with a trowel and stones are inspected manually
36
What are the limitation of surber sampling?
They can only be used where the water flow is fast enough to carry organisms into the net
37
What's the method for use of plankton nets?
A fine mesh is pulled through the water, different mesh sizes are used for different organisms
38
What are the limitations of plankton nets?
Nets with a coarse mesh size do not catch smaller organisms and nets with a fine mesh may become clogged by phytoplankton, preventing water flow
39
What is colonisation media?
Monitoring populations by providing suitable habitats that they may colonise
40
What are the limitations of colonisation media?
Not all species can be colonised as they may not use the media and accurate population estimates are not possible as the proportions that colonise the media are not known
41
What are pitfall traps?
A container is placed in a hole in the ground with it's open end making a close-fit with the soil and the top being level with ground-surface
42
What is the method for pitfall traps?
A cover is supported over the opening to exclude predators and rain flooding, the trap is checked after a standardised measure of time, a preservative fluid may be used to kill captured animals for later study
43
What are the limitations of pitfall traps?
Only mobile species of ground-surface are caught, trapped carnivorous animals may kill each other, if a preservative is used it may attract or repel certain animals and some species avoid traps or can escape
44
What are beating trays used for?
Sample invertebrates present on vegetation above ground
45
What's the method for beating trays?
A sheet or tray is placed beneath the vegetation which is beaten several times with a stick, the invertebrates are dislodged and removed for counting
46
What are the limitations for beating trays?
It is difficult to standardise the method between researchers, some species aren't dislodged, thicker branches shake less, some species fly away and higher branches cannot be reached
47
What are light traps used for?
Collect night-flying insects that are attracted by bright lights usually UV lights
48
What are the limitations of light traps?
Moths only fly during their adult phase and activity is affected by the weather and seasons so failure to find a species doesn't mean species is absent and the brightness and light wavelengths emitted by the light can affect their attractiveness
49
What are Tüllgren funnels used for?
Sample mobile invertebrates in leaf litter or soil
50
What's the method for Tüllgren funnels?
A sample of leaf litter or soil is placed on a mesh beneath a light, the light and heat repel some mobile organisms which move down and away into a container, this is left for a standard period of time
51
What are the limitations to Tüllgren funnel?
Only species that are repelled are collected, some organisms may die or stop moving, some organisms are too large to pass through the mesh
52
What suction samplers used for?
Capture airborne insects or invertebrates that were dislodged from vegetation
53
What's the method for a suction sampler?
The suction sampler will capture the insects through various methods and the cross-section is known to calculate population density
54
What are the limitations of suction samplers?
Some invertebrates may not be caught by an air sampler, they may sense it and fly away and some insects may not be dislodged from vegetation
55
What are the methods of earthworm extraction from soil?
Soil flooding and soil pit extraction
56
What is the method of soil flooding for earthworm extraction?
Mark out an area and remove any vegetation, add irritant to area and surrounding area until saturated, continue and remove any earthworm that surface for standardised time period
57
What are the limitations of soil flooding for earthworm extraction?
Irritant solution may not percolate some soils, worms may move sideways or down, worms may not move, worms may die and worms may move too slowly for time period selected
58
What is the method for soil pit extraction for earthworm extraction?
A pit of standardised size is collected and the sample is searched by hand
59
What are the limitations of soil pit extraction?
Smaller worms may be overlooked and digging may disturb worms that move sideways or down, out of the sample site
60
What are the limitations to the use of species ID keys?
Some species lack characteristic features and look the same as other species and the characteristic features may not always be present (flowers, seeds and breeding plumage)
61
How are species categorised by abundance?
DAFOR
Dominant, abundant, frequent, occasional, rare
62
What are the limitations to the use of abundance scales?
Judgement is subjective and results aren't quantitative so statistical tests cannot be done
63
What is species frequency?
Measure of the dispersal of species by recording the proportion of all samples in which it was found
64
What are the limitations to the Lincoln index?
Marked organisms more susceptible to predation, paint may wear off, paint may damage organisms, marked individuals may not mix freely with the rest of population
65
How can we help ensure samples are representative?
Random/systematic sampling, method of picking sample sites, standardisation of methods
66
What are some examples of imagery being used in ecological research?
Image databases, motion-sensitive cameras and closed circuit TV (CCTV),
67
How are image databases used for ecological research?
Recognition of individuals using unique features
68
What unique features can be identified in image databases?
Stripes, Cheetah tail markings, Whale Shark spot patterns, dolphin fin marks and injuries
69
What are the limitations of image databases?
Few species have features that make them identifiable
70
What can motion-sensitive cameras be used for?
Habitat monitoring to detect the presence or activity of animals
71
What are some specialist techniques used in ecological research?
Imagery, marking, DNA databases, auditory monitoring, position monitoring, data recorders, sensor carrier systems, indirect evidence
72
What can DNA profiles be used for?
Identify individuals, gene pools and other genetic relationships
73
What is eDNA?
Environmental DNA found in shedding of cells in the environment (particularly fish)
74
When is auditory monitoring used?
For the detection of species that cannot be seen
75
What are sonograms used for?
Evidence of animals such as dolphins, bats and some insects' presence, abundance and activity
76
What can be used to track animals in freshwater or air?
GPS, radio and acoustic transmitters
77
What is position monitoring used for?
Measuring the movement of individuals
78
What can be used to track animals in seawater?
Acoustic transmitters as they give real-time info fo the current position
79
When are geolocators used?
When transmitter may be too heavy or the battery won't last long enough for a long-term study
80
What do geolocators detect?
Time and light
81
What are the disadvantages to geolocators?
The animal has to be recaptured to download the data
82
What is some indirect evidence of a species presence?
Nests, droppings, feeding marks, owl pellets, footprints and territorial marks
83
What abiotic factors can be measured with electronic meters?
Temperature, pH, dissolved oxygen, light levels and wind or water velocity
84
How can the accuracy of electronic meters be improves?
Calibration must occur
85
How can humidity be measured?
Whirling hygrometer and electronic humidity meter
86
How does the whirling hygrometer work?
It has two thermometers, one of which is wet, it's then spun and as the water evaporates it cools, the rate of cooling is measured and then compared to a table of results
87
What measure wind velocity?
Anemometer
88
How can an anemometer be standardised?
Distance from ground, no obstacles from air flow, axis of rotation controlled and impeller type anemometers must face into the wind
89
What are the methods of measuring water turbidity?
Secchi disc and turbidity bottle
90
What is the method to using a secchi disc?
Lower the disc into the water until the black and white sectors cannot be distinguished and record the depth of the disc
91
What are the limitations to secchi disc?
Depth judgment is subjective, sunlight may affect visibility and water may not be deep enough
92
What is the method to using a turbidity bottle?
Add a standard depth of water to a turbidity bottle, the hatched circles are observed to see which are obscured and note the coarsest circle which cannot be distinguished
93
What are the limitations of turbidity bottles?
Judging the circles is objective and light levels may effect visibility
94
What are the method of measuring the concentration of ions within a solution?
Test strips, electronic colorimeter and ion selective electrodes
95
What is the method to using test strips?
The test strips have bands of reagents that change colour when they react with the ion to be measured, the strips are dipped into the solutions being analysed and then compared with a reference colour chart
96
What is the method to using electronic colorimeter?
A reagent is added to the test solution, the intensity of the colour produced is measured by a light meter that is adjusted to measure a specific wavelength of light
97
What is the method to using ion selective electrodes?
An electronic probe is put into the test solution, the electrode potential that is produced by the solution between the two electrodes is used as a measure of the ion concentration
98
What are the limitations to measuring the ion concentration in solutions?
Presence of other ions can lead to inaccurate results
99
What is the method for use of soil sieves?
Stack sieves in order of mesh size and allow the soil to filter through, this can isolate a component or test the proportion of each element of the soil
100
How does sedimentation of soil work?
Soil is filled in a cylinder half full and then topped up with water and inverted few times, the soil will separate by component
101
What is a soil triangle?
A triangular graph used to display the combined proportions of the three mineral soil components, different areas of the graph represent soils with characteristic properties
102
How is soil water content measured?
Heat at 100 degrees for 24 hours, weigh and reweigh then calculate
103
How is soil organic matter content measured?
Heat dry soil strongly in a furnace or bunsen burner, needs to be less than 550 degrees otherwise minerals may break down to release gas, wait until constant mass and then calculate
104
What is soil bulk density?
Mass of dry soil per unit volume
105
How can the volume of soil sample be controlled?
Use of a soil auger to a controlled depth
106
What are the methods of detecting soil pH?
Colorimetry and electronic pH meter
107
What are the two methods of colourimetry?
Indicator solution or indicator paper
108
What is the method for indicator solution?
Add barium sulphate to soil sample to help particles settle and then add water and universal indicator solution, shake thoroughly and leave to stand for 15
109
What is the difference when testing with indicator paper?
The same procedure just without the solution and dip paper into water and compare with a colour chart
110
What are the limitations of colorimetry?
The colour chart can be subjective
111
What are the limitations of pH electronic meter?
Regularly calibrating the probe with buffer solutions makes this method less convenient than papers
112
415-420 not yet learnt
