1.1-b) Sampling Animals and Plants Flashcards
1
Q
- Compare the differences between qualitative and quantitative data.
A
-
Qualitative:
➞ is descriptive, and regards data that can be observed, but not measured.
↳ (used to inform on what species are present) -
Quantative:
➞ regards information about quantities, and therefore numbers.
↳ (allows for statistical analysis and interpretation of trends)
2
Q
- Describe the purpose of a representative sample?
A
- Sometimes a population is so large that it would be impractical to sample every individual.
- In this case, a representative sample of the population is selected.
- If a population has a wide range of variations, then a larger representative sample is needed.
3
Q
- What are the 3 principles of a representative sample?
A
- The sample should have the same mean as the population as a whole.
- The sample should have the same degree of variation about the mean as the population as a whole.
- The sample should be a large sample.
4
Q
- What are the 3 main strategies for obtaining a representative sample?
A
-
Simple Random:
➞ each member of the population has an equal chance of being sampled
↳ (e.g. random quadrat sampling) -
Systematic:
➞ members of a population are selected at regular intervals
↳ (e.g. sampling an ecosystem every 10 metres along a transect) -
Stratified:
➞ the population is divided into categories and then sampled proportionally
↳ (e.g. sampling of three distinct habitats)
5
Q
- Describe the importance of species monitoring.
A
- It is important to identify and monitor species for several reasons:
1. monitoring population change 📉
2. monitoring invasive species ❗
3. monitoring pollution using indicator species ☢️
4. monitoring the discovery of new species ✨
6
Q
- Discuss pollution monitoring and indicator species.
A
-
Indicator species can be used to determine the impact of pollution on an environment.
➞ The presence, absence or abundance of certain living organisms show if an environment is affected by a particular set of environmental conditions.
↳ (e.g. Lichens can tolerate different levels of atmospheric sulfur dioxide)
7
Q
- Explain what the measurement ‘DENSITY’ is when using quantative techniques?
A
-
Density:
➞ is the number of individuals of the same species pesent per unit area or unit volume.
8
Q
- Explain what the measurement ‘RELATIVE ABUNDANCE’ is when using quantitative techniques?
A
-
Relative abundance:
➞ is how common or rare a species is relative to other species in a defined area or community
(expressed as a percentage of the total number of organisms in an area)
9
Q
- Explain what the measurement ‘FREQUENCY’ is when using quantitative techniques?
A
-
Frequency:
➞ is the chance of finding a species within a defined area and the number of percentage of samples in which a particular species occurs
↳ (e.g. a quadrat)
10
Q
- Explain what the measurement ‘PERCENTAGE COVER’ is when using quantitative techniques.
A
-
Percentage cover:
➞ is a measure of the amount of cover of a particular species in a quadrat.
11
Q
- Explain what the measurement ‘DISTRIBUTION’ is when using quantitative techniques?
A
-
Distribution:
➞ is the manner in which a group is arranged geographically and can change seasonally, in response to resource availability and in response to other external factors.
12
Q
- Explain what a transect is.
A
- A transect is a sampling method which investigates the distribution of organisms in relation to a fixed area by recording all the species found at points, or in a quadrat placed in certain intervals along a line.
13
Q
- Explain the 3 different methods for using transects.
A
-
Line:
➞ A line is drawn through the habitat.
Any species touching the line is counted and recorded (e.g. a piece of string placed along a habitat and the number of dandelions touching the line can be counted). -
Belt:
➞ A quadrat is placed continuously along a transect line of a known length and width (e.g. quadrats placed continuously along a line of a river bank). -
Point:
➞ Sampling using simple, random, or systematic methods at known points along the transect line (e.g. quadrats placed every 10m along a transect line).
14
Q
- What are the limitations of using quadrats to sample the environment and the potential solutions?
A
- Organisms in a quadrat may be wrongly identitified
➞ a.) use a resource (e.g. internet) to identify unknown organisms (+ paired statement keys, reverse imageing, photographs, etc) - Organisms in a quadrat may be wrongly counted
➞ b.) Establish a common rule for counting organisms (i.e. plants/organisms that are half in/out) - Sample may not be representative of the ecosystem
➞ c.) Take several samples and calculate an average (mean)
15
Q
- Explain the ‘capture-mark-recapture’ technique (Lincoln Biodiversity Index)
A
- The ‘capture-mark-recapture’ technique can be used to estimate the size of a population (invertebrates and vertebrates)
- After random sampling has been carried out, the Lincoln Biodiversity Index can be used to determine an estimate of the total population.
- A sample of the population is captured and marked (M) and released.
- After an interval of time, a second sample is captured (C)
➞ (which allows the population to mix - to have an equal chance of all members of the population to be in the second sample) - The number of recaptures (R) in the second sample is counted.
- The total populaton is found using the formula:
➞ Total population (N) = (M x C) /R
16
Q
- Compare the lists of invasive and non-invasive sampling techniques.
A
-
INVASIVE:
1. Quadrats
2. Pitfall traps
3. Net sampling
➞ Sweep nets (insects)
➞ Mist nets (birds/bats)
➞ Drip nets (fish)
4. Capture-mark-recapture
5. Tree beating
6. Pooters -
NON-INVASIVE:
1. Drones
2. Camera traps
3. Thermal cameras
4. Observational data
5. Audio recording
6. Motions sensor cameras
7. Faecal sampling
8. Hair trapping
17
Q
- What is a biotic indice?
A
-
Biotic indice:
➞ is a scale showing the quality of an environment based on the types of organisms that inhabit it.
18
Q
- What is the Trent biotic index?
A
-
Trent biotic index:
➞ a measure which uses freshwater invertebrates to compare water quality at different points in a stream or river.
↳ These species are indicator species, which give information regarding the quality of the environment based on their presence, absence, or abundance. - Scores range from 0 for highly polluted water to 15 for clean water.
19
Q
- What is the Simpson’s diversity index?
A
-
Simpson’s diversity index:
➞ a measure of diversity which takes into account the number of species present, plus the relative abundance of each species. - The value of D ranges from 0 to 1:
➞ 0 represents infinite diversity = better health of an ecosystem
➞ 1 represents no diversity = worse health of an ecosystem
20
Q
- Explain ‘validity’.
A
-
Validity:
➞ is the measure of how well a test measures what it is meant to measure (related to variables)
21
Q
- Explain ‘reliability.
A
-
Reliability:
➞ is the ability of an experimental design to give stable and consistent results (measure of consistency)
22
Q
- Suggest ways in which the validity of sampling could be increased.
A
- Ensuring your variables are kept constant
- Ensuring sampling time/location is kept the same
- Using multiple sampling methods to confirm this trend (triangulation)
- Comparing findings from your study to previous studies
23
Q
- Suggest ways in which the reliability of sampling could be increased.
A
- Taking more samples
- Repeating the experiment
- Using a larger number of pieces of sampling equipment (e.g. multiple bat detectors)