Field Techniques for Biologists

Question 1

What is a risk assessment?

Answer 1

A risk assessment is a document that identifies the potential hazards, assesses the likelihood of them occurring and clearly describes the steps that can be taken to minimise their occurrence, therefore reducing the possibility of injury or loss.

Question 2

Give 5 examples of hazards and risks associated with fieldwork. Describe them.

Answer 2

terrain - refers to how the land lies. Variations in terrain may include uneven surfaces, flat areas, hills and steep gradients. Assessing this prior to setting out and selecting appropriate footwear is essential;
weather conditions - these can change very quickly in the field. A weather forecast should be consulted before setting out, and appropriate clothing, footwear and supplies selected. In extreme weather, fieldwork may have to be postponed or abandoned;
isolation - areas where fieldwork is carried out can often be isolated. Making sure that others who are not going into the field are aware of the route and the expected time of return is essential;
tidal changes - these can change very quickly. Tide tables should be consulted prior to setting out.

Question 3

How should sampling be carried out?

Answer 3

Sampling should be carried out in a manner that minimises impact on wild species and habitats.

Question 4

What must consideration be given to?

Answer 4

Consideration must be given to rare and vulnerable species and habitats which are protected by legislation. Since legislation may change with regional areas, these should be researched prior to beginning sampling.

Question 5

Describe the use of quadrats.

Answer 5

Quadrats are used to sample slow moving or stationary organisms. Quadrats involve a direct count of what is in the frame or a percentage cover can be estimated. Frequently a 10x10 grid is used to give a quick percentage abundance score.
Quadrats are often thrown to get a random sample. To ensure random sampling a random number generator or random number table is used.

Question 6

Describe a line transect.

Answer 6

A transect is a line along which different samples can be taken. Transects are particularly useful for sampling areas where there is a transition of species from one habitat to another as environmental conditions change.
Quadrats of a suitable size and shape for the area are placed along the transect at regular intervals, allowing organism abundance to be recorded. Transects are a form of systematic sampling.

Question 7

Describe a belt transect.

Answer 7

Belt transects uses two parallel lines and record the plants found between the lines at given points.

Question 8

Why may a photograph or satellite image with a superimposed grid be used?

Answer 8

• To sample things which move
• Where sampling would damage the area
• Where it is difficult to remain for the count
• To cut down intrusion and disturbance of the sample area.

Question 9

Describe random, stratified and systematic sampling.

Answer 9

Random sampling- individuals selected from the larger population must be chosen completely by chance.
Stratified sampling- in some cases, one large population may be divided up into smaller sub-populations first. Individuals are then randomly selected from each sub-population.
Systematic sampling- may be taken at regular intervals, e.g. every 2 metres along the transect.

Question 10

Describe pitfall traps.

Answer 10

Pitfall traps can be modified in terms of:
- Size
- Access (e.g. fall triggered by size)
- Baited or not
- Result of the fall (lethal or not)
Pitfalls are only effective for animals that are on the ground

Question 11

Describe the three types of nets.

Answer 11

Sweep Sampling (air or water)
Water sweep nets are often designed to allow the water to flow out while collecting the organisms.
Malaise Traps
Malaise traps are large, tent-like traps to catch flying insects.
Flight Intercept Traps
Flight intercept traps are fine black or white mesh that the insects fly into. Simplest design is just a screen.

Question 12

Describe pan traps

Answer 12

Pan traps can tempt in flying insects. These are brightly coloured shallow dishes with liquid that has a low surface tension (e.g. soapy water). Insects will be attracted to the colour, fly in, and drown.

Question 13

Describe camera traps

Answer 13

For animals which are difficult to capture and where you want to avoid contact, camera traps are used.
These are cameras which are activated by the animal as it approaches, normally using motion sensors or triggers like breaking a light gate.
These allow direct observations without interfering with the natural behaviour of the animal.
These have been particularly useful in observations of elusive species such as nocturnal activity of animals like leopards.

Question 14

Describe scat sampling.

Answer 14

Scat sampling is an indirect method of sampling. It can give a lot of information on the animals you are studying.

• Number
• Range
• DNA sampling
• Food/Diet
• Health

Question 15

How may identification of a sample be made?

Answer 15

Identification of a sample can be made using expertise, classification guides, keys or laboratory analysis of DNA (including mitochondrial and chloroplast DNA), protein or other molecules, such as carbohydrates.

Question 16

How is life generally classified>

Answer 16

Life is generally classified according to relatedness

Question 17

What does being familiar with taxonomic groupings allow for?

Answer 17

Being familiar with taxonomic groupings allows predictions and inferences to be made between the biology of an unknown or lesser-known organism and better-known (model) organisms.

Question 18

What are model organisms?

Answer 18

Model organisms are those that scientists already know a lot about and have been studying for many years.

Question 19

Give examples of model organisms.

Answer 19

E. Coli, drosophila, yeast, maize, mice and zebra finches

Question 20

What is phylogenetics?

Answer 20

The use of sequence data has allowed more detailed maps of the relationships between organisms to be produced.

Question 21

What has phylogenetics helped to do?

Answer 21

it has helped to map out relationships that can become obscured or confused due to divergent or convergent evolution

Question 22

What is divergent evolution?

Answer 22

accumulation of differences as species from a common ancestor undergo changes over time.

Question 23

What is convergent evolution?

Answer 23

similar structures that have evolved from different ancestries.

Question 24

What are the 3 domains of life?

Answer 24

1. Archaea
2. Bacteria
3. Eukaryota

Question 25

What are the 5 divisions of the plant kingdom?

Answer 25

Mosses
Liverworts 
Ferns 
Angiosperm 
Gymnosperm

Question 26

What are mosses?

Answer 26

flowerless plants which lack seeds and a vascular system

Question 27

What are liverworts?

Answer 27

flowerless, spore-producing plants with flattened stems and overlapping leaves

Question 28

What are ferns?

Answer 28

flowerless plants that reproduce by producing spores and which have a vascular system

Question 29

What are gymnosperms?

Answer 29

flowerless plants that produce seeds for reproduction and which have a vascular system, e.g. the conifer

Question 30

What are angiosperms?

Answer 30

flowering plants.

Question 31

What are the 5 phyla of the animal kingdom?

Answer 31

Chordata 
Arthopoda
Nematoda
Platyhelminthes
Mollusca

Question 32

What are chordata?

Answer 32

the sea squirts and vertebrates, e.g. birds, mammals, reptiles, amphibians and fish

Question 33

What are arthopoda?

Answer 33

the joint-legged invertebrates which are identified by their segmented body, typically with paired appendages, e.g. wasps, butterflies, spiders and crabs;

Question 34

What are nematoda?

Answer 34

the round worms which show great variety, many of which are parasitic, e.g. tapeworms;

Question 35

What are platyhelminthes?

Answer 35

the flatworms, many of which are parasitic, show bilateral symmetry, lack a body cavity, but do contain internal organs;

Question 36

What are mollusca?

Answer 36

the molluscs which are greatly varied, with many characterised by the presence of a shell, e.g. snails and octopi.

Question 37

Why is monitoring populations essential?

Answer 37

Monitoring populations is essential in understanding environmental conditions.

Question 38

What does presence, absence or abundance of particular indicator species give information about?

Answer 38

Presence, absence or abundance of particular indicator species can give information of environmental qualities, such as the presence of pollutants.

Question 39

Name a method used for estimating population size.

Answer 39

Mark and recapture is a method for estimating population size.

Question 40

Describe the mark and recapture method.

Answer 40

A sample of the population is captured, marked and released (M). The marking technique used must have minimal impact on the species being studied, thus does not interfere with the individual’s normal behaviour or make it more conspicuous to predators. It must, however, also be clear in order to permit subsequent observations. After an interval of time, a second sample is captured (C). If some of the individuals in this second sample are recaptures (R), then an estimate of the total population (N) would be calculated using the formula:
• N = estimate of total population
• M = number captured, marked and released in first sample
• C = number captured in second sample
• R = number of marked recaptures in second sample

Question 41

Give 4 assumptions made during the mark and recapture method.

Answer 41

• all individuals have an equal chance of capture;
• there is no immigration or emigration during the sample time;
• there is no birth and death during the sample time;
• sampling methods used each time are identical.

Question 42

What are the 5 methods of mark making?

Answer 42

banding 
tagging 
surgical implantation 
painting 
hair clipping

Question 43

Describe banding.

Answer 43

Metal bands with an individual identifier are attached to the animal where it will not impede their movement.
If it will not be possible or appropriate to physically recapture different colours of bands or sequences of colour bands can be used for remote idenfication (e.g. through binoculars)
Often used on birds, attached to the leg. e.g. penguin chicks are tagged early to track their colony.

Question 44

Describe tagging.

Answer 44

Tags will vary according to the species you are tracking. The tag is used for remote tracking e.g. radio transmitters.
The tag has to be securely attached, but also not interfere with the animals normal behaviour. e.g. transmitters attached to turtle shells.

Question 45

Describe surgical implantation.

Answer 45

Tags can be implanted to prevent them interfering with the animal. For example, external tags on fish make a large difference to their streamlining.
Since the animal undergoes a surgical procedure there are implications for their welfare and for their expertise required. e.g. tracking striped bass.

Question 46

Describe painting.

Answer 46

Non-toxic, biodegradable paints must be used. Care must also be taken that the paint does not block skin surfaces for heat regulation, secretion or respiration.
It is also important to consider the impact of scent and colour marking on animals. e.g. hedgehogs in Guernsey.

Question 47

Describe hair clipping.

Answer 47

A clearly identifiable section of hair removed can be used as a very effective method of identification.
Care has to be taken regarding; size of clipping, distress to animals, social signals with animals. e.g. tracking mice in field studies.