Metazoa
Met•a•zo•a
(ˌmɛt əˈzoʊ ə)n.
| Noun | 1. |  Metazoa - multicellular animals having cells differentiated into tissues and organs and usually a digestive cavity and nervous system |
| 单词 | metazoa | |||
| 释义 | MetazoaMet•a•zo•a(ˌmɛt əˈzoʊ ə)n.
MetazoaMetazoa(mĕt'əzō`ə), subkingdom of the animal kingdom comprising the multicellular animals in the traditional two-kingdom system of taxonomic classification, in which living organisms were considered to be either plants or animals. Metazoa included all animals except the protozoans, formerly classified as in the phylum Protozoa but now classified in the kingdom ProtistaProtistaor Protoctista , in the five-kingdom system of classification, a kingdom comprising a variety of unicellular and some simple multinuclear and multicellular eukaryotic organisms. ..... Click the link for more information. . The term is still used informally. MetazoaThe kingdom (or subkingdom) comprising all many-celled animals, whether constructed of simple tissue layers or of complex organs. In some five-kingdom systems and in the six-kingdom systems of classification for living organisms, metazoans constitute a separate kingdom, while in the older two-kingdom and some three-kingdom systems the subphylum Metazoa made up the greater part of the kingdom Animalia. Most usual classifications subdivide the Metazoa into about 30 phyla of many-celled animals (such as Arthropoda or Mollusca), each representing a major kind of body design. In all classifications, the only animal forms not included in the Metazoa are the single-celled protozoa (Protista) and the independently evolved sponges (Parazoa). See Animal kingdom, Eukaryotae, Porifera, Protista Metazoans are made up of eukaryotic cells, each with a membrane surrounding the nuclear material and with the mechanics of cell multiplication always involving the mitotic division of chromosomes. Cellular specialization is common. In addition to increasing functional interdependence and specialization of cells, the evolution of the higher phyla of Metazoa has involved the potentialities and penalties of increasing size, particularly those associated with the surface-mass ratio. Despite differing grades of structural and functional complexity, interdependence of organs, tissues, and cell types is diagnostic of the phyla of animals making up the kingdom (or subkingdom) Metazoa. See Classification, biological, Homeostasis Metazoa[‚med·ə′zō·ə]metazoaMetazoa[met″ah-zo´ah]Met·a·zo·a(met'ă-zō'ă),metazoaA multicellular animal with a nervous system and tissues. The widely preferred term is “animal”.Met·a·zo·a(met'ă-zō'ă)metazoaAll the members of the animal kingdom that consist of more than one cell. All animals more complex than the one-celled PROTOZOA.Metazoa
Synonyms for Metazoa
|
|||
| 随便看 |
|
英语词典包含2567994条英英释义在线翻译词条，基本涵盖了全部常用单词的英英翻译及用法，是英语学习的有利工具。