Distribution of Organisms Flashcards
Why do organisms live in different places?
Because the environment varies from place to place
What is a habitat?
A place where an organism lives
What is the distribution of an organism?
Where an organism is found
What environmental factors affect where an organism is found?
Temperature, availability of water, availability of O2 and CO2, availability of nutrients and availability of light
How can you study the distribution of organisms?
By using a quadrat to measure how common an organism is in two sample areas, or by placing quadrats along a transect to study how distribution changes across an area
What is a quadrat?
A square frame made of metal or wood
How do you work out the population size of an organism in a sample area?
Work out the mean number of organisms per m2 then multiply the mean by the total area of the habitat
What do you have to make sure when using quadrats and transects?
That the results are reliable: reproducible and repeatable
What 2 ways can you make your results more reliable?
Take a larger sample size by using as many transects and quadrats as possible, and use random samples in multiple different spots
For your results to be valid the have to be …?
Reliable
What makes an experiment reproducible?
If it is repeated by another person or by using different equipment or techniques and the same results are obtained
What makes an experiment repeatable?
If the original experimenter repeats the experiment using the same method and equipment and obtains the same results
How do you make an experiment valid?
Control all the variables
