Research Methods Flashcards
1
Q
What does accuracy mean?
A
A measure of how close the recorded result is to the real value.
2
Q
What does precision mean?
A
The intervals between possible recorded results e.g. a ruler that measures in millimetres is more precise then one that measures in centimetres.
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 similar. Repeating the study should show weather it is a real result or was caused by other variables.
6
Q
What is a valid study?
A
Produces precise, accurate, reliable, results upon which conclusions can be based.
7
Q
What are the components of carrying out scientific fieldwork?
A
- Appropriate risk assessment
- Practical equipment and materials required and how to use safely
- Data to be collected and analysed:
- using appropriate apparatus to record quantities measurements and to measure biotic/abiotc factors
- selecting the correct sampling techniques
- selecting the correct statistical test
8
Q
What are the general principles of scientific research?
A
- Identifying a topic of interest
- Finding out what has already been learnt
- Formulating a hypothesis and null hypothesis
- Designing and carrying out an experiment to test the hypothesis
- Designing the investigation = sampling location, time, size of sample, standardised technique, stats test
- Analysing the results and drawing conclusions
- Planning further research needed to fill gaps in existing knowledge
9
Q
When sampling why does sample location matter?
A
To avoid the introduction of bias caused by the deliberate selection of locations for the convenience or to support or dismiss a hypothesis.
10
Q
What is random sampling?
A
If the study has a regular shape then a grid can be laid out and the coordinates of sampling sites selected using random numbers.
If the study area has an irregular shape then all the possible sampling sites can be numbered and selected using a number generator.
11
Q
What is systematic sampling?
A
This involves samples taken using a chosen interval distance or spacing. The choice of sampling sites is not based on choices made by observable differences in the study area.
Distance between sampling sites should be selected to detect variability without collecting more data then necessary, this can be determined using a preliminary study.
12
Q
When sampling why does sample timing matter?
A
If the factor being measured changes with time, then it will be necessary to sample on different occasions to produce a mean result that represents the typical value.
Ideally time intervals depend on the rate at which valued change = preliminary study
13
Q
When sampling why does sample size matter?
A
If the variable is not homogenous then larger samples are more likely to produce representative results.
- preliminary study
14
Q
When sampling why does the number of samples matter?
A
The number of samples needed to produce a representative mean depends upon the degree of scatter around the mean.
The degree of scatter values around the mean can be assessed using the Standard Deviation.
It is easier to assess the degree of statistical significance of the results with larger sample sizes.
15
Q
When sampling why does standardising the techniques matter?
A
To allow comparison of the results that are collected at different times, in different locations or by different researchers, they must all be collected in exactly the same way.
16
Q
Why are good surveys essential for wildlife conservation programmes?
A
- to find out which species are present
- to monitor the habitat conditions, how the change etc
- to monitor features of populations and how they change over time such as:
- population size
- age structure
- growth rates
- breeding rates
- territory size
- populations movements
17
Q
What is a quadrat and what is it used for?
A
It is a study area, within which populations can be studied.
The results from many quadrats can be scaled up to estimate the overall situation for an entire area
18
Q
What size should a quadrat be?
A
Lichens = 10cm x 10cm
Ground flora = 0.5m x 0.5m
Trees in a forest = 100m x 100m
Bird presence survey = 10km x 10km
19
Q
What are the three types of quadrats?
A
- Open quadrats = mark out a study area
- Grid quadrats = sub divided into smaller squares e.g. 10 x 10 each representing 1%
- Point quadrats = used when ground flora is too tall and would be flattened by others quadrats, a wooden frame supports 10 metal rods, each time a rod touches a leaf it counts as 10% cover
20
Q
What are the limitations of quadrats?
A
- Subjective judgement may be involved
- Quadrat frame may flattery or move plants
21
Q
What is a pond net and the method to use it?
A
Pond nets sweep through water or aquatic vegetation to capture invertebrates, amphibians or fish
- using a particular sweep length or number of sweeps can help to standardise the method
22
Q
What are the limitations of pond nets?
A
Mobile species may escape
23
Q
What is kick sampling and what is the method to use it?
A
Kick sampling collects invertebrates that live on river beds
- net with its straight edge on the river bed and its face open to the current
- riverbed in front of the net is disturbed by kicking a boot over it
- controlling the number of of kicks and length of kick can be used to standardise it
24
Q
What are the limitations of kick sampling?
A
- accurate standardisation is difficult
- buried organism of those fixed to stones may not be dislodged
- some organisms can swim and avoid the net
- water flow rate is variable
- fragile organisms can be destroyed
25
What is a surber samples and what is method to use it?
Provide a more standardised technique
- fixed are of riverbed is sample with a box-like frame
- river bed is disturbed using a trowel and stones are inspected manually
- netting at the side of the net opening reduces the number or organisms that escape
26
What are the limitations of surber samplers?
- can only be used where the water flow is fast enough to carry organisms
- samplers small size can make it difficult to set on rough substrates in deep water
27
What is a plankton net and what is the method to use it?
Catch planktonic organisms floating in water
- a fine mesh is pulled trough the water and can be used vertically or horizontally
- net can be fixed where there is a current or towed
28
What are the limitations of a plankton net?
- nets with course mesh size do not catch smaller organisms
- nets with a fine mesh may become clogged by phytoplankton, preventing water flowing through the net
29
What is a sweep net and what is the method to use it?
- sturdy best used to sample invertebrates in ground vegetation such as grassland, it is swept so the organisms are dislodged and caught
- standardisation = same number of sweeps and length of sweep
30
What are the limitations of sweep nets?
- mobile species may escape such as flying insects
31
What are aerial insect nets and what is the method to use them?
These are lightweight nets used to capture flying insects such as butterflies
32
What are the limitations of aerial insect nets?
Successful collection depends on the agility of the researcher and prey
33
What is colonisation media and what is the method to use it?
Some species can be monitored by providing suitable habitats that they may colonise
34
What are the limitations of colonisation media?
- not all species can be monitored as they may not use the media
- accurate population estimates are not possible as the proportion that colonise the media is not known
35
What are pitfall traps and what is the method to use it?
Pitfall traps are used to sample mobile animals on the ground surface
- container is place on a hole with its open end making a close fit with the soil and the top being level with the ground surface
- a cover supported over the opening stops predators, or rain getting in
- trap is checked after a standard period of time
- a preservative fluid may be used to kill animals for later study
36
What are the limitations of pitfall traps?
- only mobile organisms
- trapped carnivorous animals may kill other organisms
- preservative may attract or repel certain species
- some species avoid traps or can escape
37
What is a beating tray and what is the method to use it?
Used to sample invertebrates present of vegetation above the ground
- tray is placed under the vegetation which is beaten several times, invertebrates are dislodged and collected on the tray
38
What are the limitations of beating trays?
- difficult to standardise
- some species are not dislodged
- some species fly away
- higher branches cannot be reached
- thicker branches shake less
39
What is a light trap and what is the method to use it?
Used to collect night-flying insects that are attracted to bright lights
- fall into a container, after being attracted to light (UV)
40
What are the limitations of a light trap?
- moths only fly during their adult phase and activity is affected by weather and seasons
- hard to compare traps with different brightnesses
41
What is a tullgren funnel and what is the method to use it?
Used to sample mobile invertebrates in leaf litter or soil
- sample of leaf litter or soil placed onto mesh beneath light
- the light and heat repel the mobile invertebrates which move down through the mesh and fall into a container
42
What are the limitations of a tullgren funnel?
- only species repelled by heat and light will be collected
- some may die
- some are too large
43
What are suction samples are what is the method to use it?
Used to capture airborne insects that were dislodged from vegetation
- air suction captures flying insects
- motor driven can be used to sample invertebrates on ground vegetation
- Pooter is used to pick up vertebrates that have been found and are in a tray
44
What are the limitations of suction samplers?
- may sense the air sampler and fly away
- some may nit be dislodged by the suction
45
In terms of earthworm extraction from soil what is soil flooding and how do you do it?
- mark out an area
- remove vegetation
- add irritant e.g. mustard water
- keep adding till soil is saturated
- saturate the surrounding area
- collect worms that surface
- continue collecting until no more worms appear fora time period
- count and measure
46
What are the limitations of soil flooding?
- irritant may not percolate through impermeable soils
- irritant may not reach deepest worms
- worms may move down or sideways
- worms may not move
- worms may die
- worms may move too slowly
47
In terms of earthworm extraction from soil what is soil pit extraction?
A pit of a chosen area and depth is dug up
- soil is hand sorted and worms collected
48
What are the limitations of soil pit extraction?
- smaller worms may be overlooked
- digging may disturb worms and they may move down or sideways
49
What is population size/density?
To estimate the numbers of organisms of a particular species within a population or per unit area
50
What is abundance scales?
Involve allocating species to different categories based on their relative abundance e.g. the DAFOR scale:
- Dominant
- Abundant
- Frequent
- Occasional
- Rare
51
What is species richness/diversity?
A measure of the number of different species found in an area, often focusing on a particular taxonomy e.g. birds, or reptiles
52
What is species frequency?
A measure of the dispersal of a species by recording the proportion of al samples in which it was found
A high species frequency shows the species is generally distributed
53
What is species density?
The number of species found to a specific area and makes species richness results more comparable e.g. number of species per square metre
54
What is percentage vegetation cover?
Estimated by observing the proportion of:
- ground that is covered by vegetation or ground flora
- sky that is obscured by vegetation for tree cover
- grid quadrats are usually used
55
What is Lincoln index? And capture recapture?
Estimates the total population by catching a proportion of the population:
- sample is caught, counted, marked, released
- appropriate amount of time later, a second sample is caught and counted, and marked individuals are counted
- Lincoln index used to estimate population
number in 1st sample x number in 2nd sample
Total population = —————————————————————
Number in second sample with marks
56
What are the limitations of Lincoln’s index?
Relies on assumptions:
- animals are all mobile and can be caught
- size of population doesn’t change due to deaths, births, immigration, emigration
- being caught and marked doesn’t affect their rate of survival
- marked individual properly reintegration
- all individuals have the same chance of being caught
57
What is Sampson’s index of biodiversity?
Used to asses the variety and abundance of species in an area.
N(N-1)
D = ————
Sum of(n(n-1))
N = total number of individuals of all species
N = number of individuals of a particular species
58
What are species identification: ID keys?
Often dichotomous keys where a sequence of questions narrows sown the possibilities
Based on unique visible features: size, shape, markings
59
What are the limitations of ID keys?
- some species lack characteristic features and look the same as other species
- characteristic features may not always be present
60
How are image databases used as a specialist technique in ecological research?
- Individual of some species can be recognised from image databases of unique feathered e.g. tigers facial stripes, cheetah tail markings, whale shark spots, dolphin fin marks, zebra stripes.
Provides information on:
- territory size
- population movements such as migrations
- lifespans
- social groupings
61
What are the limitations of image databases?
Few species have unique feathers that can be used to identify individual animals
62
How are motion-sensitive cameras used as a specialist technique in ecological research?
Used for habitat monitoring to detect the presence or activity of animals, using visible light photography or infrared at night
63
How are closed circuit TV (CCTV) used as a specialist technique in ecological research?
Used to observe animal behaviour with a lower risk of disturbance than if researchers visit the site e.g. birds nests
64
How is marking/tagging used as a specialist technique in ecological research?
Used to be able to identify individual which have already been caught, e.g. rings on birds
- provides information on lifespans and movements
65
How are DNA databases used as a specialist technique in ecological research?
DNA profiles can be used to identify individuals, gene pools and other genetic relationships
66
How can DNA databases be used to detect the presence of a species?
DNA shed into the environment can be collected this is called eDNA
- it can be used to prove a species is existing in a area and give cause to protect that area.
67
How can DNA databases identify regional populations?
Each separate population within a species has its own unique gene pools
- so it may be possible to identify where a plant or animal came from
- this is being used to identify the sources of timber, elephant ivory and illegal trade is coming from
68
How is auditory monitoring used as a specialist technique in ecological research?
Some species cannot be seen but can be detected by the sounds they produce
E.g. sonograms are records of the sounds made by taxa such as dolphins, bats and some insects
69
How is position monitoring used as a specialist technique in ecological research?
- radio, gps, acoustic transmitter can be used to track animals in air or freshwater
- acoustic transmitters used for seawater
- give real time information of the current position of the animal carrying the transmitter
- geolocator tags may be used where transmitters are too heavy, or battery life too short
70
How are data recorders used as a specialist technique in ecological research?
Collect data on a range of abiotic factors e.g. temperature, light, salinity, pressure
The data may be downloaded when the recorder is recover by radio or auditory transmission
71
How are sensor carrier systems used as a specialist technique in ecological research?
If data is collected in a single location then the sensor just need to be placed there but it is often necessary to have a carrier system to move the sensor to the study areas:
- ROV = remotely operated vehicles - drones
- AUV = automatic unmanned vehicles
- balloon
- aircraft
- satellite
- animals
72
How are satellite systems used as a specialist technique in ecological research?
- reflected visible light provides images of large areas of earths surfaces
- infrared emitted by the earth can be used to monitor vegetation density and temperature
- weather monitoring
- radar microwaves:
- wind velocity
- sea surface altitude
- wave height
- oil pollution
73
How is indirect evidence used as a specialist technique in ecological research?
- nets/burrows
- droppings - diet, gender, territory
- feeding marks - chewed nuts
- owl pellets - diet
- tracks/footprints
- territorial marks - scratching posts
74
How can electronic metres measure abiotic factors?
They can measure temperature, pH, dissolved oxygen, light levels and window water velocity
- Metres must be calibrated by adjusting its reading to be the exact as a meter that is known to be accurate and if a meter cannot be adjusted than the percentage error should be noted so the results can be adjusted
75
How can light intensity be measured?
Calibrated light meter can be used to measure the light intensity the method must be standardised, especially in the sensor orientation
76
How can humidity be measured?
- whirling hygrometer = using two thermometers one being dry and the other is wet, they are spun. The wet bulb is called by the evaporation of the water. The dry bulb is not cooled, the rate if evaporation on the wet bulb depends on the humidity, so the temperature difference between the two thermometers can be compared with a table of values to estimate the humidity. Scan an accurate reading the hygrometer must be spun until there is no further cooling.
- Electronic humidity meter = must be calibrated to ensure that the readings are accurate
77
How can wind velocity be measured?
Using an anemometer, which must be standardised by:
- Distance from the ground
- No obstacles to airflow
- Access of rotation must be horizontal or vertical
- Impeller type anemometer must face the wind
78
How can water turbidity be measured using a secchi disk?
And what are the limitations?
Using a secchi disc:
- Lower the secchi disc into the water until the black and white sections cannot be seen
- Record the depth of the disc
Limitations:
- Depth judgement is subjective
- Sunlight levels may affect visibility
- Water may not be deep enough for the segments to become indistinguishable
79
How can water ability be measured using a turbidity bottle?
And what are the limitations?
- add a standard depth of water to a turbidity bottle
- The hatch circles at the bottom of the bottle are observed to see which are obscured
- Note the coursest circle which cannot be distinguished
Limitations:
- Judging which circles can be distinguished to subjective
- Light levels may affect visibility
80
How can the concentration of ions in solution be measured?
(Hint = there are three methods)
- test strips = have bands of the reagent that change colour when they react with the ion to be measured, the strips are dipped into the solution being analysed and then compared with the colour reference chart
- Electronic colorimeter = a reagent is added to the test solution and the intensity of the colour produced is measured by a light meter that is adjusted to measure a specific wavelength of light
- Ion selective electrodes = the electronic pro is put in the test solution, the electrode potential that is produced by the solution between the two electrons is used as a measure of the iron concentration
However, the presence of other ions can lead to inaccurate test results
81
How could soil temperature be measured?
Using a soil of thermometer:
- Thermometer must have a protective metal tube to prevent it breaking
- Push the thermometer into the soil to a standard depth
- Protect the thermometer from direct sunlight
- Leave it there until the alcohol liquid stops moving and a constant temperature is shown
- The temperature is red while the thermometer is still in the soil
82
How can soil texture be measured?
(Hint there are two methods)
Soil sieves:
- A dried crushed soil sample is placed in the top sieve
- The stack is shaken by hand or mechanically for two minutes the particles drop through the sieves until they reach a sieve where the holes are too small to pass through
- Each proportion is weighed and the percentage composition of the three proportions is calculated
Sedimentation method:
- Large objects are removed from a dried soil sample using a 2 mm or by hand
- Soil was crushed to ensure the particles of separated
- Measuring cylinder is filled halfway with soil and then topped up with water
- The top is sealed and then the cylinder is shaken repeatedly by inverting it
- The suspension is allowed to settle
- The total depth of the settled soil components is measured after two minutes two hours and two days
- The proportion of the total volume of each texture category can then be calculated
83
How can soil water content be measured?
- Soil sample is collected using a standardised technique such as a course sampler or auger
- Soil sample is placed in a sealed bag to prevent water loss by evaporation
- Larger mineral particles invisible organisms are removed
- The basin is heated at about 100°C for 24 hours
- The basin is re-weighed and reheated until constant masses reached
- The percentage of water content can then be calculated
Wet soil mass - dry soil mass/ wet soil mess x 100
84
How can soil organic matter content be measured?
- A dry sample is placed in a pre- weighed crucial which is re- weighed
- The crucible is heated strongly in a furnace or Bunsen burner
- The crucible is reward
- It is heated to 550°C
- Which is repeated into a constant mass is reached
Dry soil mass - burnt soil mass/ dry soil mass x 100
85
How can soil bulk density be measured?
Soil bulk density is the mass of dry soil per unit volume
- Volume of a soil sample can be controlled by using a soil auger of known cross-sectional area and pushing it into the soil to a chosen depth
- Dry soil mask can be found by weighing the soil after it’s been heated about 100° to a constant weight
86
How can soil pH be measured using colorimetery?
Using universal indicator solution:
- Add 2.5 cm³ of soil to a test tube
- Add 1 cm³ of barium sulphate which helps the soil particles to settle
- Add 3.5 cm³ of distilled water
- Add 10 drops of universal indicator solution
- Firmly push a bung into the top
- Shake thoroughly and leave to stand for 15 minutes
- Compare the colour of the solution with a colour chart
Using universal indicator papers:
- same method for universal indicator solution but instead of using the solution paper and instead and compare to a colour chart
However, using a colour chart is subjective
87
How can soil pH be measured using electronic pH metres?
- The pH meter should be calibrated using buffer solutions known of pH
- The meter should be left to stabilise for long enough to give stable readings
- The probe should be inserted into a standard depth
Limitations:
- The need to regularly calibrate the probe with both solutions makes this method less and convenient than the universal indicator papers
