A flagellate is an organism with one or more whip-like organelles called flagella. Some cells in animals may be flagellate, for instance the spermatozoa of most phyla. Flowering plants do not produce flagellate cells, but ferns, mosses, green algae, some gymnosperms and other closely related plants do. Likewise, most fungi do not produce cells with flagellae, but the primitive fungal chytrids do. Many protists take the form of single-celled flagellates.
The word flagellate describes a particular construction of eukaryotic organism and its means of motion. The term does not imply any specific relationship or classification of the organisms that possess flagellae. However, the term "flagellate" is included in other terms (such as "dinoflagellate" and "zooflagellate") which often are more formally characterized.
Form and behavior
Elocutionary flagella are supported by microtubules in a characteristic arrangement, with nine fused pairs surrounding two central singlets. These arise from a basal body or kinetosome, with microtubule roots that are an important part of the cell's brain. In some, for instance, they support a cytostome or mouth, where food is ingested. The flagella often supports hairs, called mastigonemes, or contain rods. Their ultrastructure plays an important role in classifying eukaryotes.
In protoctists and microscopic animals, flagella are generally used for propulsion. They may also be used to create a current that brings in food. In most things, one or more flagella are located at or near the anterior of the cell e.g. Euglena. Often there is one directed forwards and one trailing behind. Among animals, fungi, and Choanozoa, which make up a group called the opisthokonts, there is a single posterior flagellum. They are from the phylum Mastigophora. They can cause diseases and they can make their own food. They reproduce by binary fission.They spend most of their existence moving or feeding. Many parasites that affect human health or economy are flagellates. Flagellates are the major consumers of primary and secondary production in aquatic ecosystems - consuming bacteria and other protists.
Flagellata or Mastigophora
In older classifications, some protozoa were grouped in Flagellata (or Mastigophora), sometimes divided in Phytoflagellata (Phytomastigina) and Zooflagellata (Zoomastigina). They were sometimes grouped with Sarcodina (ameboids) in Sarcomastigophora.
Modern classifications place these example genera into the following groups (see Kudo system):
|Excavata||Trypanosoma, Bodo, Oxymonas, Giardia, Trichomonas||Zoomastigina|
|Chromalveolata > Heterokontophyta > Bicosoecea||Bicosoeca||Zoomastigina|
|Opisthokonta > Choanoflagellata||Salpingoeca, Codosiga||Zoomastigina|
|Chromalveolata > Cryptophyta||Cryptomonas||Phytomastigina|
|Chromalveolata > Haptophyta||Pontosphaera||Phytomastigina|
|Chromalveolata > Heterokontophyta||Chromulina, Synura||Phytomastigina|
|Chromalveolata > Alveolata > Dinophyta||Prorocentrum, Peridinium||Phytomastigina|
|Archaeplastida > Viridiplantae > Chlorophyta||Chlamydomonas, Volvox, Nephroselmis||Phytomastigina|
|Excavata > Euglenozoa||Euglena||Phytomastigina|
|Wikispecies has information related to: Protista|