4.3

objective 4.3- descibe the use of quadrats as a technique for sampling the
distribution of organisms in their habitats.



sample has to be random
so it is not bias.
a sample also needs to be representative
so the samples need to cover a wide area

number the strings in a quadrat 1-10 (if ten strings)

select 2 random numbers.

then use these to selsct a square to count the organisms.

repeat this 10 times and divide the number of all the organisms together by 10 if repeating this 10 times. preferably cover 10% of the area you are surveying

4.2

4.2- recall the use of quadrats to estimate the population size of an organism in two different areas

a quadrat- method of sampling
quadrat size range between 0.25x0.25m to 1x1m
quadrat is a square grid
quadrats can be made of wood, metal, string or plastic
it helps compare the population in two different places.
you place the quadrat down and count the number of organisms within the grid and you do this sevral times and average it in each area

4.1

objective 4.1- understand the terms population, community, habitat and ecosystem.



*an ecosystem is a community of organisms
*abiotic means non-living, for example daylight, temperature, rainfall humidity, and slope of area.
*a community is a population of different species interacting with eachother.
*a habitat is a community including all the abiotic factors
*a species is an organism that reproduce to give fertile offspring
*a population is the number of individuals of a particular species.