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In this activity you will be examining organisms that you collect from the lakes and rivers near our camp. Why do you think it is important or interesting to study stream-bottom organisms or other aquatic organisms? Step #1: Collecting Organisms Physical observations of the water
You will instructed on collection techniques at the river or lake. In general, you will use a net or a screen with handles to collect organisms. 1. Select a site along the river or lake bank which has visible rocks and is shallow. One person will hold the net and the other one will gently (very gently) disturb the surrounding water and rocks to bring organisms to the surface. 2. Dump the contents of the net into either a plastic container or petri dish containing river or lake water. After several rounds, in which you think you have collected enough head back for observations. Step #2: Making observations Observations of organisms The types of organisms you collect may be several different kinds. They may be phytoplankton or zooplankton or possibly larger macroinvertebrates. It is up to you to determine based on their physical features the basic classifications of the organisms. Phytoplankton
Zooplankton
If the organisms are too small to be seen with the hand lens, carefully place them on a slide in a drop of water and locate them in the microscope. Sketch below and on the next page the organisms that you find. Write down descriptions of the organisms as you see them. SKETCHES AND DESCRIPTIONS OF ORGANISMS (Several pages left blank for sketches) Something to Think About... 1. Based on your observations, what types of organisms did you find in the water? 2. Adaptations are characteristics that organisms have that help them live in their environment. What types of adaptations did you see in these organisms? 3. Why might some stream organisms not be present in large amounts? |
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