Invertebrate Zoology Amoeboid Protozoans


Like flagellates, amoeboid protozoans (amoebae) do not form a monophyletic group. When feeding and moving, all members of the informal grouping "amoeboid protozoans" form temporary cell extensions called pseudopodia. The most familiar amoebae are naked (no test or shell) and are normally found on shallow-water substrates of freshwater ponds, lakes, and slow-moving streams, where they feed on other protists and bacteria. Other amoebae have a protective shell or test with pseudopodia projecting through an opening in the test. A few amoebae are parasites of humans and other animals.

Amoeba eating an oil droplet

Amoeboid Protozoans

1.      Move by means of pseudopodia

2.      Most are free-living and heterotrophic; a few are obligate parasites

3.      Most reproduce asexually by binary fission

4.      Body surrounded only by its own cell membrane, shape changes continuously

5.      Single type of nucleus


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