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Exploring the Microbial World

Part F: Another organism from Domain Eukarya, Kingdom Protista

Next, let's take a look marine microorganism called a Foraminifera. These Protists are more like animals because they do not contain chloroplasts. Instead they capture food with long, thin, retractable pseudopodia that stream through the pores in their shells.

This is a photo of a living planktonic foraminifera with its psuedopodia radiating outward.

Foraminifera typically have internal skeletons made of calcium carbonate and composed of a series of chambers arranged in a spiral. Although many Foraminifera species live on the ocean bottom, a few are planktonic and can be very abundant. They are so abundant that when their shells sink to the sea floor they create a layer of calcareous ooze. Geologists study the chemical composition of these shells, as well as species distributions, to learn about past climates.

Here is a picture of the skeletons of several species of planktonic foraminifera like you'll find in your kit.

Observations

View the Foraminifera slide entitled "Globigerina" under the microscope. Follow the same procedure as you did for the last few slides, starting with the 4x objective, moving to the 10x objective, and finally to the 40x objective. On your worksheet, sketch what you see under both the 10x (low power) objective and the 40x (high power) objective. Be sure to label each drawing with the correct magnification. Also, be sure to answer the questions on your worksheet.

When you are finished, LEAVE THE SLIDE ON THE MICROSCOPE, AND TAKE YOUR WORKSHEET UP TO THE FRONT DESK TO GET CHECKED OFF FOR LAB POINTS.

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