Distribution of organisms
- Created by: chelsey866
- Created on: 07-03-14 17:08
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- Distribution of organisms
- Organisms live in different places because the environment varies
- The distribution of an organism is where an organism is found
- Where an organism is found is affected by environmental factors, such as:
- The temperature
- How much water there is
- The amount of light
- How much oxygen and carbon dioxide there is
- If there are enough nutrients around
- An organism might be more common in one area than another due to differences in environment factor between the two areas
- To study the distribution of an organism you can use quadrats or transects
- Use quadrats to study the distribution of small organisms
- You can see how common an organism is in two different areas- these are called sample areas
- 1) Place a 1m2 quadrant on the ground at a random point within the first sample area.
- E.g. divide the area into a grid and use random number tables to pick coordinates
- 2) Count all the organisms within the quadrat
- 3) Repeat steps 1 and 2 as many times as you can
- 4) work out the mean number of organisms per quadrat with the first sample area
- 5) repeat steps 1-4 in the second sample area
- Finally compare the two means
- E.g. you might find 1 daisy per m2 in the shade, and 7 daisies per m2 in the open field
- Population size
- Population size= mean No of organisms per 1m2 quadrat X total area ( in m2 )
- E.g. there are 7 daisies per m2 in a 100m2 field. so population size= 7x100=700 daisies
- Population size= mean No of organisms per 1m2 quadrat X total area ( in m2 )
- Organisms live in different places because the environment varies
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