Amoebae are single-celled, crawling organisms often found in ponds. They have no definite shape and consist of flowing cytoplasm encased in a very flexible cell membrane. Amoebae have organelles (including one or more nuclei) and a contractile vacuole.

 

  1. Movement
  2. Amoebae move when cytoplasm flows out into a long extension of the cell; this crawling, flowing motion is called psuedopodia.
  3. Habitat
  4. Most amoebae live in pond water, moist soil or the ocean; some species are parasitic, living inside the body of another organism.
  5. Diet
  6. Amoebae ingest food through phagocytosis (the process whereby a cell engulfs a piece of food and ingests it). Basically tiny predators, they feed mainly on other microorganisms.
  7. Osmoregulation
  8. Amoebae that live in freshwater ponds must deal with water constantly rushing into the cell. Organelles called contractile vacuoles constantly fill with excess water, and pump it out of the cell. Without a contractile vacuole, the amoeba would explode in a freshwater environment.
  9. Size
  10. Although they are fairly large cells, most amoebas are too small to see with the naked eye; however, some species grow to grape size.

REPRODUCTION:
Binary Fission in amoeba:
Most single celled organisms use the method of binary fission for cell division and reproduction. These include paramoecium, bacterium, and finally amoeba. In this paragraph we will be focusing on amoeba’s cell division which is also its method of reproduction. In binary fission the amoeba consists of one parent which forms the 2 daughter cells. First, the amoeba cell undergoes nuclear division and replicates into two nuclei. The two nuclei divide and move to opposite directions in the parent cell. The cell then produces protiens and nutrients in preperation for binary fission. In the stage of binary fission, the cell divides and forms 2 daughter cells. This process generally occurs when environmental conditions are most favourable. That is, when there is enough food, water, and a favourable temperature.

Bibliography:

http://en.wikipedia.org/wiki/Fission_(biology)

http://www.scienceclarified.com/Al-As/Amoeba.html

http://www.enchantedlearning.com/paint/subjects/protists/amoeba.shtml

Advertisements