Carry out a quantitive survey of animals in an ecosystem

Question 1

What is used to estimate the number of plants and animals that don’t move too fast?

Answer 1

Quadrats and transects

Question 2

What method is used to calculate the number of moving animals in a habitat?

Answer 2

Capture-recapture method

Question 3

Explain the capture-recapture method.

Answer 3

Capture a number of animals of the same species, marking them and releasing them unharmed. On a second visit a few days later, a similar number of animals are collected. Some of these will be marked.

Question 4

What formula is used for the no. of animals in habitat using capture-recapture method?

Answer 4

no. caught and marked on first visit X no. caught on second visit

divided by

no. marked on second visit

Question 5

Name three animals the capture-recapture method can be used for.

Answer 5

deer (tagged), snails, crabs

Question 6

What 4 following assumptions are involved for capture-recapture technique?

Answer 6

1) marking mustn’t harm the animals (making them more visible to predators).
2) animals mix evenly in the habitat (not bunched like colonies of ants).
3) animals are restricted to a local area.
4) marked animals are given time to mix with the unmarked population.

Question 7

Give a reason as to why it is important marking the animals doesn’t harm them?

Answer 7

Make them more visible to predators