Sampling Techniques

Question 1

Why do scientists use sampling methods?

Answer 1

They want to study the biodiversity of a region by using the species distribution and population, they can’t study the entire area.

Question 2

What are some sampling techniques used by scientists?

Answer 2

1. Observation
2. Quadrat
3. Line transect
4. Belt transect
5. Pooters

Question 3

What are Quadrats?

Answer 3

A quadrat is a frame made of metal, PVC or wood that is used to study the distribution and density of plants and slow-moving animals in a particular area.

Question 4

How do you use a quadrat?

Answer 4

1. Place them randomly, several times within the ecosystem
2. Count the number of individuals of each species of plant and slow-moving animal in the quadrat area.
3. If you can’t distinguish the plants, use the grid to estimate the percentage coverage.
4. Look at the results from several quadrats in an area.

Question 5

When are random and systematic sampling used?

Answer 5

Random - when the vegetation distribution is uniform, toss it over the shoulder with your eyes closed.
Systematic - when the distribution of different species is uneven.

Question 6

How do we determine species or density?

Answer 6

Count the number of organism in all the quadrats and then average them by the number of quadrats thrown. in /m^2

Question 7

How do we determine species frequency?

Answer 7

Frequency = #of quadrats containing organism/ # of quadrat throws.
in %

Question 8

How do we determine the species distribution?

Answer 8

Divide the number of squares filled by the number of squares present. in %.

Question 9

What is a Line transect?

Answer 9

A tape or string that has marks at regular intervals that is used to measure the distribution of organisms. The plants and the slow-moving animals actually touching the line at each mark are recorded.
They are useful where there is a transition of organisms (down a rocky seashore) due to an abiotic factor.

Question 10

What is a belt intersect?

Answer 10

Made by placing two parallel line transects together. It records all the species found between the two lines and how far apart they are from each other.

Question 11

What are the methods of collecting organisms?

Answer 11

1. Pooter
2. Beating tray
3. Sweep nets
4. Pitfall traps

Question 12

What is a Pooter?

Answer 12

A method of collecting small organisms. By sucking on a tube, small animals are drawn into a glass tube or test tube.

Question 13

What is a beating tray?

Answer 13

A large white sheet placed on the ground, supported by struts and held below a tree. The tree is shaken to dislodge the animals.

Question 14

What are Nets?

Answer 14

They catch flying insects and aquatic animals and plants.

After collecting the aquatic animals, they are placed in a jar for counting

Question 15

What is a Pitfall trap?

Answer 15

Cans or jars buried in the ground and filled with paper or cardboard to provide shelter and covered with a lid or stone to keep out rain.
This is useful for collecting ground dwelling insects that are often nocturnal.

Question 16

What is a Pitfall trap?

Answer 16

Can or jars buried in the ground filed with paper and a lid to keep out rain. This is used for ground dwelling and nocturnal insects.

Question 17

What is a Tullgren funnel?

Answer 17

A device used to collect small animals or insects from a sample of soil or leaf litter.
The sample is placed on a coarse sieve with a light bulb. The light bulb dries and warms the sample causing the animals to fall into a collecting dish.

Question 18

What is mark-release-capture?

Answer 18

Animals are captured, marked inconspicuously with non-toxic substances and released back into their habitat. The animals along with non-marked ones are collected at a later date.
Total numbers in population = # captured and marked x number captured/ number recaptured that were marked.