Amoeba

From Encyclopedia Jr, free information reference for Kids

Alternate meanings: Amoeboid, Amoebozoa

For the operating system, see Amoeba distributed operating system. For the record store, see Amoeba Music.

Amoeba is a genus of protozoa that moves by means of temporary projections called pseudopods, and is well-known as a representative unicellular organism. The word amoeba or ameba is variously used to refer to it and its close relatives, now grouped as the Amoebozoa, or to all protozoa that move using pseudopods, otherwise termed amoeboids.

Amoeba itself is found in freshwater, typically on decaying vegetation from streams, but is not especially common in nature. However, because of the ease with which they may be obtained and kept in the lab, they are common objects of study, both as representative protozoa and to demonstrate cell structure and function. The cells have several lobose pseudopods, with one large tubular pseudopod at the anterior and several secondary ones branching to the sides. The most famous species, Amoeba proteus, is 700-800 μm in length, but many others are much smaller. Each has a single nucleus, and a simple contractile vacuole which maintains its osmotic pressure, as its most recognizable features. It obtains its food by phagocytosis.

Early naturalists referred to Amoeba as the Proteus animalcule, after a Greek god who could change his shape. The name "amibe" was given to it by Bery St. Vincent, from the Greek amoibe, meaning change.

A good method of collecting amoeba is to lower a jar upside down until it is just above the sediment surface. Then one should slowly let the air escape so the top layer will be sucked into the jar. Deeper sediment should not be allowed to get sucked in. It is possible to slowly move the jar when tilting it to collect from a larger area. If no amoeba are found, one can try introducing some rice grains into the jar and waiting for them to start to rot. The bacteria eating the rice will be eaten by the amoeba, thus increasing the population and making them easier to find.

[edit] In popular culture

• Writer Tom Robbins states in the preface to his book Even Cowgirls Get the Blues, that amoebas are cool because they reproduce by binary fission, so the first amoeba is still alive to this day.
• In the 1984 computer game Boulder Dash, Rockford, the main character, is chased all the time by a constantly-growing amoeba.
• In certain places of Brazil, the term amoeba (in its Portuguese form: ameba) is used as a derogatory slang for "slow, obtuse person".
• The contemporary British Poet, John Hegley, has a poem entitled Amoeba.
• The Adolescents have a song titled Amoeba
• The Powerpuff Girls and Demashita! Powerpuff Girls Z have a trio of villains called The Amoeba Boys, who are shown to be lacking in their capacity for true villainous activity (as in one episode, where they steal an orange from a street vendor, and then give it back) compared with world-domination-centered villains such as Mojo Jojo. This seems to be explaining by their lack of brain (being single-celled organisms).
• The 48th produced episode of the classic Star Trek series (The Immunity Syndrome) featured an 11,000-mile (~17 700 km) wide amoeba threatening the life of not only Captain Kirk and his crew, but all life throughout the galaxy.
• Rogue Amoeba Software, LLC is a privately held software company that creates audio tools primarily for Mac OS X.
• In the fourth installment of The Legend of Zelda (Ocarina of Time), the dungeon boss of the Water Temple is a giant Amoeba that fuses with the water around it.
• Video game, Ratchet and Clank: Up Your Arsenal, have Amoeboids in the level, Aquatos.
• In the Super Sentai series, Bakuryuu Sentai Abaranger, the villains, the Evoliens, are actually highly evolved amoeba-like aliens.

amebas do not reproduce as they have an unknown source of birthing.

They also have the largest known genome of any organism, over six humdred billion base pairs.

[edit] External links

• : compare size of cells
• Amoeba info