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	{{otheruses}}
	{{Taxobox\|
	\| name = ''Amoeba''
	\| color = khaki
	\| image = Chaos diffluens.jpg
	\| image_width = 250px
	\| domain = ]
	\| kingdom = ]
	\| class = Rhizopoda
	\| order = ]
	\| familia = Amoebidae
	\| genus = '''''Amoeba'''''
	\| genus_authority = ], 1822
	\| subdivision_ranks = Species
	\| subdivision =
	'']''<br>
	'']''
	{{Expand-section\|date=June 2008}}
	}}

	'''''Amoeba''''' (sometimes '''''amœba''''' or '''''ameba''''', plural '''''amoebae''''') is a ] of ] that moves by means of ]s, and is well-known as a representative ]. The word '''amoeba''' or '''ameba''' is variously used to refer to it and its close relatives, now grouped as the ], or to all protozoa that move using pseudopods, otherwise termed ]s.

	==History==
	The amoeba was first discovered by ] in 1755.<ref>{{cite journal \| last = Leidy \| first = Joseph \| title = Amoeba proteus \| journal = The American Naturalist \| volume = 12 \| issue = 4 \| year = 1878 \| pages = 235–238 \| url = http://links.jstor.org/sici?sici=0003-0147%28187804%2912%3A4%3C235%3AAP%3E2.0.CO%3B2-7 \| accessdate = 2007-06-20 \| doi = 10.1086/272082}}</ref> Early naturalists referred to ''Amoeba'' as the ''Proteus animalcule'' after the ] god ] who could change his shape. The name "amibe" was given to it by ]<ref>http://books.google.com/books?id=1I8DAAAAQAAJ&pg=PA158&lpg=PA158&dq=%22bory+de+saint+vincent+jean+baptiste+genevieve+marcellin%22+amibe&source=web&ots=SCcqmYPPSy&sig=vje4JuVmdQzWrFqpXTw2UjRsgx8#PPA5,M1</ref>, from the Greek ''amoibè'', meaning change.<ref name = EOS1>{{cite book \| first = Kimberley \| last = McGrath \| coauthors = Blachford, Stacey (eds.) \| title = Gale Encyclopedia of Science Vol. 1: Aardvark-Catalyst (2nd ed.) \| year = 2001 \| isbn = 078764370X \| publisher = Gale Group}}</ref>

	==Habitat and uses==
	''Amoeba'' itself is found in decaying ], in ] and ] water, wet soil, and animals.<ref name = EOS1/> Due to the ease with which they may be obtained and kept alive, they are common objects of study as representative protozoa and to demonstrate cell structure and function.

	==Anatomy==
	]
	The cell's ]s and ] are enclosed by a ], obtaining its food through ]. Amoebae have a single large tubular ] at the ] end, and several secondary ones branching to the sides. The most famous species, '']'', is 700-800 ] in length but the species '']'' is as large as a millimeter, and visible to the naked eye. Some ameobas have an appendage designed specifically for the phagocytosis of silicone{{Fact\|date=May 2008}} . Its most recognizable features include one or more ] and a simple contractile ] to maintain ]. Food enveloped by the amoeba is stored and digested in vacuoles. Amoebae reproduce via ]. In cases where the amoeba are forcibly divided, the portion that retains the nucleus will survive and form a new cell and cytoplasm, while the other portion dies. Amoebas also have no definite shape.<ref name = SC>{{cite web \| url = http://www.scienceclarified.com/Al-As/Amoeba.html \| language = english \| format = html \| publisher = Scienceclarified.com \| title = Amoeba \|

	== Reaction to stimuli ==
	=== Hypertonic and hypotonic solutions ===
	Like most cells, amoebae are adversely affected by excessive ] caused by extremely saline or dilute water. Amoebae will prevent the influx of salt in saline water, resulting in a net loss of water as the cell becomes ] with the environment, causing the cell to shrink. Placed into ], amoebae will also attempt to match the concentration of the surrounding water, causing the cell to swell and sometimes burst.<ref name=Patterson1981>{{cite journal \| author = Patterson, D.J. \| year = 1981 \| title = Contractile vacuole complex behaviour as a diagnostic character for free living amoebae \| journal = Protistologica \| volume = 17 \| pages = 243–248}}</ref> Adjusting the tonicity of the cytoplasm can also damage the digestive enzymes used in phagocytosis, allowing the amoeba to ingest food but not extract energy, resulting in death.<ref name = EOS1/>

	=== Amoebic cysts ===
	{{main\|Microbial cyst}}
	In environments which are potentially lethal to the cell, an amoeba may become dormant by forming itself into a ball and secreting a protective membrane to become a ]. The cell remains in this state until it encounters more favourable conditions.<ref name = SC/> While in cyst form the amoeba will not replicate and may die if unable to emerge for a lengthy period of time.

	=== Marine amoeba ===
	Marine amoeba lack contractile vacuoles and their ]s and organelles are not damaged by the salt water found in seas, oceans, salt swamps, salty rivers and ponds.

	==In popular culture==
	{{Trivia\|date=July 2008}}
	<!--

	Please add all the meanings which are not directly related to the biological creature to ].

	-->
	*] states in the ] to his 1976 novel '']'' that amoebas are ] because they ] by ], so the first amoeba is still alive to this day. The first sentence of the book is "Amoebae have no fossils."
	* In the 1984 computer game ], Rockford, the main character, interacts frequently with a constantly-growing green amoeba.
	* The contemporary British Poet, ], has a poem entitled ''Amoeba''.
	* ] have a song titled "Amoeba"
	* ] and ] 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 explained by their lack of brain (being single-celled organisms).
	* The 48th produced episode of the classic ] series (]) featured an 11,000-mile (~17 700 km) wide amoeba threatening not only the life of Captain Kirk and his crew, but all life throughout the galaxy.
	* In the fourth installment of ] (]), the dungeon boss of the Water Temple is a giant Amoeba that fuses with the water around it.
	* Jon Scieszka's book, '']'', had a poem called ''Amoeba where are you aneba"
	* In the second epidode of ], Bender says to Fry that he hasn't "touched his amoeba" in a sushi like restaurant. The amoeba is depicted as a large, green, jelly-like blob.

	==References==
	{{Reflist}}

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Revision as of 13:53, 8 July 2008

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