Phylum Rhizopoda

1. They have pseudopodia, which are used for both locomotion and feeding. Such pseudopodia are constantly changing as amoeba moves and feeds. Food particles and small organisms are engulfed using pseudopodia and digested in the food vacuoles. The digested food is assimilated into the rest of the body. This type of feeding is called phagocytosis. Ingestion is by endocytosis and egestion is by exocytosis.
2. The food vacuole and the oil droplets of amoeba confer a granular appearance to the endoplasm.
3. They possess a contractile vacuole, which carries out osmoregulation. When the contractile vacuole reaches a certain size, it fuses with the cell membrane where water is released outside the cell.
4. Their cytoplasm has two distinct regions; viscous outer layer ectoplasm (plasmagel) and more fluid internal endoplasm (plasmasol).

1. They are single-celled eukaryotes and their cells have no definite shape.
2. They are unicellular whose bodies are surrounded by membranes. Their cytoplasms have two distinct regions, the plasmasol (inner) and plasmagel (outer).
3. Most of them are free living, forming important links in the food chains. They feed on plant and animal materials. In contrast, others are parasitic or infectious to animals, including human being; some human pathogens such as Entamoeba histolytica cause amoebic dysentery.
4. They reproduce asexually by binary fission.
5. They move by using pseudopodia; hence, amoeba and other protoctists using this mode of locomotion are called pseudopods

1. They have a defined /conspicuous cytoplasm – plasma gel in the plasmasol.
2. Stored in cytoplasm are food vacuoles.
3. There is an elaborate spherical nucleus with chromatin blocks and karysome this referring to the nature, the number, the type of chromosomes chromatins are the chromosome in the stages of development.
4. They exist in two body forms i.e. small and large. By some mechanism not known, the smaller form transforms into the larger form, which are similar in structure.
5. The locomotary organelle is a single pseudopodium.
6. The outer covering is all bound by a single plasma membrane/ cell membrane.
7. Food vacuole of smaller one contains bacteria at different stages of digestion.
8. The food vacuole of larger one contains the digested gut epithelial cells of red blood cells at different stages of digestion.

Diagram of Entamoeba histolytica

The adaptations can be divided into three major parts,

1. Structural adaptation.
2. Physiological adaptation/modification.
3. Reproductive adaptation.

1. There is only one pseudopodium since it does not need to move from place to place as the free living amoeba as it has most of the requirements in its environment.
2. There is no contractile vacuole indicating that cytoplasmic contents of entamoeba are isotonic to the most environments.
3. Isotonic-having a concentration such that it neither gains no loses water by osmosis.

1. They can vary/change the diet from bacteria to animal cells and produce the necessary enzymes for digestion.
2. They can live in conditions where oxygen content is very low, however when they puncture a capillary and ingest a red blood cell (as they live on epithelial), they can respire aerobically.
3. They require little amount of energy as movement is limited.

1. Like all parasites, entamoeba produces a larger number of off springs so that they survive the hazards of the environment as they move from one host to another.
2. They reproduce asexually by binary fission and large numbers of cysts are produced each giving rise to 8 daughter amoebulae.
3. The cysts are viable under variable environmental conditions and can survive in alternative hosts thus increasing the chance of survival.

NB; Entamoeba histolytica causes amoeba dysentery which is characterized by abdominal pains, nausea, vomiting and fever.

Under severe attacks, ulceration develops and blood is released into the intestine and out of the body through frequent motion which contains blood and mucus.

The parasite (i.e. Entamoeba) can affect the kidney, the liver and the brain.