Biology(investigating an ecosystem)

the biosphere is the part of the planet where organisms are found

the biospere can be divided into smaller units called ecosystems

the place where an organism lives is called a habitat

If we want to learn about a particular habitat, we need to carry out an investigatio which involves

collecting the organisms

identifying the organisms

measuring the physical conditions

we cannot collect all the organisms in a habitat, so we must take a sample

using a quadrat

a quadrat is used to take plant samples

frame divided into squares

thrown randomly on the area being sampled

the number of squares containing the plant being studied are counted

using a pitfall trap

used to take animal samples

cup placed in a hole, making sure the top is level with the ground so that the animals fall in

however, some may be eaten by other animals which fall in

a key must be used

a branching key

a paired statement key

a physical, non-living factor, such as light, moisture, oxygen, concentration or temperature

affect the organisms living in a particular habitat

can normally be measured using a meter

measuring...

moisture

a moisture meter is used

to avoid errors, make sure you place the moisture meter firmly in the ground and wipe it dry afterwards

light

a light meter is used

to avoid errors, be careful not to shade the meter and always hold it in the same way when making the reading

green plants are not found in areas with low light intensity-reason why-plants need light for photosynthesis

most land organism are not found in very dry or very wet areas-reason why-in very dry conditions they become dehydrated. in very wet conditions plant roots are deprived of oxygen.