B4 - Sampling and Indentifucation

Question 1

What problems do biologists face when investigating where organisms live?

Answer 1

• there are many different organisms

- they seem to live all over the place

Question 2

Define the terms distribution and population

Answer 2

Distribution - the location of organisms of one species

Population - the number of organisms and of a species in an area

Question 3

What is sampling ? Describe the different methods.

Answer 3

Sampling - counting a small number of the total population and working out the total from the sample

1. Quadrats - count inside
2. Transect lines - count what touches it
3. Nets - catch butterflies or fish
4. Pooters - sucks in animals that are counted and identified
5. Pitfall traps - containers buried in ground that catches animals

Question 4

After the capture - recapture technique how can you estimate population size?

Answer 4

Number in first sample x number in second sample
___________________________________________________________
Number in second sample previously marked

Question 5

How do you sample accurately?

Answer 5

• big sample size
• repeat readings
• fair ( same equipment, placed fairly etc)

Question 6

When estimating population size after capture recapture, what are the scientists assuming?

Answer 6

Assume that no death, immigration or emigration has occurred.

Question 7

Describe how a spider key works

Answer 7

Answers to questions take the reader along one of two branches. Questions will continue until you have named the organism.

Question 8

Describe how number keys work

Answer 8

Ask questions in a list. As you answer each question , you are sent to another numbered question which continues until you reach an answer.

Question 9

What is an ecosystem?

Answer 9

All the living things and how they interact with each other and the physical conditions. It is self sufficient, which means it needs nothing supplied to it expect for energy from the sun.

Question 10

What is the difference between natural and artificial ecosystems?

Answer 10

Natural - many types of organism = large biodiversity
Artificial - fewer types of organism = lower biodiversity
- humans often control what organisms live here and remove all unwanted species

Question 11

What is zonation?

Answer 11

A gradual change in the distribution of species across a habitat