Having or consisting of many cells: multicellular organisms.
multicellularity mul'ti·cel'lu·lar'i·ty (-lăr'ĭ-tē) n.
Dictionary:
mul·ti·cel·lu·lar (mŭl'tē-sĕl'yə-lər, -tī-) ![]() |
Having or consisting of many cells: multicellular organisms.
multicellularity mul'ti·cel'lu·lar'i·ty (-lăr'ĭ-tē) n.| 5min Related Video: multicellular |
| Medical Dictionary: mul·ti·cel·lu·lar |
Having or consisting of many cells.
mul'ti·cel'lu·lar'i·ty (-lăr'ĭ-tē) n.| WordNet: multicellular |
The adjective has one meaning:
Meaning #1:
consisting of many cells
| Wikipedia: Multicellular organism |
Multicellular organisms are organisms consisting of more than one cell, and having differentiated cells that perform specialized functions in the organism. Most life that can be seen with the naked eye is multicellular, as are all members of the kingdoms Plantae and Animalia (except for specialized organisms such as Myxozoa in the case of the latter).
Contents |
Early life was most probably single celled and multicellularity has appeared dozens of times in the history of Earth.[1] In order to reproduce, true multicellular organisms must solve the problem of regenerating a whole organism from germ cells (i.e. sperma and egg cells), an issue that is studied in developmental biology. Therefore, the development of sexual reproduction in unicellular organisms during the Ectasian period is thought to have precipitated the development and rise of multicellular life.
Multicellular organisms also face the challenge of cancer, which occurs when cells fail to regulate their growth within the normal program of development.
There are various mechanisms which are disputed as being the first responsible for the emergence of multicellularity, but it is difficult to say which is correct. This is because all the suggested mechanisms are viable, but establishing which was responsible for the first multicellular life requires mostly speculation.[2]
One hypothesis is that a group of function-specific cells aggregated into a slug-like mass called a grex, which moved as a multicellular unit. Another hypothesis is that a primitive cell underwent nucleus division, thereby becoming a syncytium. A membrane would then form around each nucleus (and the cellular space and organelles occupied in the space), thereby resulting in a group of connected and specialised cells in one organism (this mechanism is observable in Drosophila). A third theory is that, as a unicellular organism divided, the daughter cells failed to separate, thereby resulting in a conglomeration of identical cells in one organism which could each then specialize.
This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)
| sporocarp (botany) | |
| louvered ceiling | |
| organ |
| Is the lion multicellular? | |
| What is a benifits of being multicellular? | |
| When did the first multicellular organisms appear? |
Copyrights:
![]() | Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2007. Published by Houghton Mifflin Company. All rights reserved. Read more | |
![]() | Medical Dictionary. The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Read more | |
![]() | Veterinary Dictionary. Saunders Comprehensive Veterinary Dictionary 3rd Edition. Copyright © 2007 by D.C. Blood, V.P. Studdert and C.C. Gay, Elsevier. All rights reserved. Read more | |
![]() | WordNet. WordNet 1.7.1 Copyright © 2001 by Princeton University. All rights reserved. Read more | |
![]() | Wikipedia. This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Multicellular organism". Read more |
Mentioned in