The Shape Shifter The Amoeba

Facts: The amoeba is a tiny, one-celled organism. You need a microscope to see most amoebas - the largest are only about 1 mm across. Amoebas live in fresh water, salt water, in wet soil, and in animals (including people).

Anatomy An amoeba consists of a single cell surrounded by a porous cell membrane. The amoeba "breathes" using this membrane - oxygen gas from the water passes in to the amoeba through the cell membrane and carbon dioxide gas leaves through it. Jelly-like cytoplasm fills most of the cell. A large nucleus within the amoeba controls its growth and reproduction.

Diet Amoebas eat algae, bacteria, plant cells, and microscopic protozoa. Some amoebas are parasites.bacteria They eat by surrounding tiny particles of food with pseudopods, forming a bubble- like food vacuole. The food vacuole digests the food.

Locomotion Amoebas move by changing the shape of their body, and oozing in random directions. The ooze forms a pseudopod. The word pseudopod means "false foot."

Pelomyxa proteus is the largest amoeba you can find in pond water. It inhabits the often oxygen poor mud on the bottom of ponds. They can become truly huge for a single celled organism. Some of them can be 5 millimeters.

I examined the sample under the microscope it looked like nothing more than dirt but between it were some big gelatinous spheres. Then I noticed that they were slowly moving!

Amoeba Proteus, the largest amoeba of them all.

Feeding Strategies These two images of Amoeba proteus shows how a ciliate is surrounded by quick developing pseudopods. The amazing thing is that the amoeba doesn’t touch the ciliate until it can't escape. Usually the pseudopods form a kind of 'dome' that makes escaping impossible. They have to have some sort of chemical detection since they notice a prey without having to touch it.

These 2 pictures show an amoeba eating. Notice the pseudopods that are used to enclose a small ciliate.

1.Nucleus 2.Contractile vacuole 3.Food vacuole 4. Pseudopod

An Amoeba is seen here splitting by cell division. When complete division is complete, there will be two new amoebas. This is what a typical amoeba could look like under your microscope. They appear as dirt until you notice they MOVE!

Things to identify on your amoeba: Nucleus Food vacuole Contractile vacuole Describe pseudopod Cytoplasm Cell Membrane Describe cytoplasmic streaming