B6.1.2

Question 1

How are animal populations estimated?

Answer 1

Through the capture-recapture technique

Question 2

The capture-recapture technique

Answer 2

1. Capture organisms from a sample area
2. Mark individual organisms, then release back into the community
3. At a later date, recapture organisms in the original sample area
4. Record the number of marked and unmarked individuals
5. Estimate the population size

Question 3

Estimating population size formula

Answer 3

Estimated population size = first sample size x second sample size

Then divide by number of recaptured marked individuals

Question 4

Sampling plants techniques

Answer 4

Using a quadrat

Using a Transect line

Question 5

What is a quadrat and how do you use it?

Answer 5

A quadrat is a square frame divided into a grid.

You place it on the ground to take a sample and record the type and number of organisms within each section.

Question 6

How do you work out the total population?

Answer 6

Total population of an organism= mean population/ m squared x total area

Question 7

What are the two types of sampling for plants?

Answer 7

Random sampling

Non random sampling

Question 8

What is random sampling?

Answer 8

Random sampling areas of plant populations- individuals are selected by chance

Question 9

What is non random sampling?

Answer 9

Non random sampling when samples are selected at specific points in the area of sampling

Question 10

Random Sampling technique

Answer 10

Mark out grid on the sample area
Use a random number generator to determine the coordinates of where to place the quadrat
Prevents bias

Question 11

Non random sampling technique

Answer 11

Set out a transect line
Samples can be taken by counting the organisms that touch the line
Or by placing a quadrat at fixed positions along the line

Question 12

What is the transect line for?

Answer 12

Transect lines are used to study how the distribution of organisms varies over a distance, samples can be taken along a line.