University:
Acadia University
Course:
BIOL 2663 | Marine Biology
Academic year:

2024
Views:

356

Pages:

10
Author:

Nabila n.

АМОЕВОIDS (AMOEBOID PROTOZOANS) An amoeboid (ameba or amoeba) is a type of cell or organism that is capable of changing its shape, mainly by extending and retracting pseudopodia or pseudopods (Greek, meaning "false feet"). They are normally found in the soil and in aquatic habitats. They move by using pseudopodia. They typically ingest their food by phagocytosis. They extend their pseudopodia to engulf a prey. They do not possess a mouth or cytostome. Amoeboids have four types of pseudopodia. These are: Lobopodia, characteristic of Amoeba, are blunt and fingerlike; Filopodia are slender and tapering, occasionally forming simple, branched networks; Reticulopodia, found in the Foraminiferans, are branching filaments that fuse to form food traps; and Axopodia, characteristic of the Actinopods (Radiolarians), are long and sticky (like reticulopodia) but radiate singly and have a stiff, internal rod composed of numerous microtubules. Amoeboid protozoans belong to three phyla. They are: Phylum Sarcodina or Sarcomastigophora: True Amoebas Phylum Actinopoda or Radiozoa: Radiolarians; and Phylum Foraminifera: Foraminiferans Phylum Sarcodina or Sarcomastigophora (True amoebas) Phylum Sarcodina or Sarcomastigophora consists of the True amoebas. The movement in sarcodinians (true amoebas) is by extending lobes of cytoplasm known as pseudopodia (or pseudopods).