# Distribution of organisms

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• Created by: Sophie
• Created on: 07-04-13 16:37

## Distribution of organisms

• habitat-where an organism lives
• distribution of a an organism affected by environmental factos:
• temperature
• avalibility of water
• avalability of oxygen & carbon dioxide
• availability of nurtients
• amount of light
• two ways to study distribution of an organism:
• measure how common an organism is in two sample areas
• study how distribution changes across an area
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• used to compare how common an organism is in two sample areas
• steps:
• choose first sample area
• divide area into grid
• pick ramdom point
• place 1m   quadrat on point
• repeat steps in first area
• work out mean
• repeat all steps in second sample area
• compare the two means

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## Population size

• work out mean mumber of organisms per m
• then mulitiply mean by total area
• example- open field is 800m squared, average of 22 daisies per m

22     800= 17600

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## Transect

• transect-lines
• how organsims are distributes across a line
• steps:
• mark out line using tape measure
• count all the organsims touching the line
• or
• place quadrats along the line (next to each other or at intervals)

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