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'''Excavata''' is a major [[supergroup (biology)|supergroup]] of [[unicellular organisms]] that are classified under the [[domain (biology)|domain]] of [[Eukaryote|Eukaryotes]]. They are characterized by an ''excavated'' feeding groove on one side of the cell body. The classification of Excavata, however, is still under debate among scientists.
{{Short description|A major supergroup of unicellular organisms}}
{{Taxobox
| name = Excavata
| image = Euglena_gracilis.jpg
| image_caption = ''Euglena gracilis'', a well-known member of the Excavata
| domain = Eukaryota
| unranked_regnum = Excavata
}}
 
'''Excavata''' is a major supergroup of unicellular [[eukaryotic]] organisms, often characterized by a feeding groove "excavated" from one side. This group includes a variety of free-living and symbiotic forms, as well as some important human parasites.


==Characteristics==
==Characteristics==
Excavata are primarily identified by the presence of an ''excavated'' feeding groove. This groove is not a universal characteristic among all members of this group, but it is a common feature. The cells of Excavata are typically [[flagellate]], meaning they possess one or more whip-like appendages called [[flagella]].
Excavata are primarily distinguished by their unique cellular structure. Many members possess a distinctive "excavated" feeding groove, which is used to ingest food particles. This groove is a key feature that gives the group its name. Additionally, many excavates have flagella, which are used for locomotion and feeding.
 
===Cell Structure===
The cell structure of excavates is diverse, but they often share some common features:
* '''Feeding Groove''': A ventral feeding groove is present in many species, used for phagocytosis.
* '''Flagella''': Most excavates have one or more flagella, which are used for movement and feeding.
* '''Mitochondria''': The mitochondria in some excavates are highly modified or reduced, especially in anaerobic environments.


==Classification==
==Classification==
The classification of Excavata is controversial. Some [[biologist]]s consider it a [[kingdom (biology)|kingdom]], while others regard it as a [[supergroup (biology)|supergroup]]. The group was proposed by [[Thomas Cavalier-Smith]] in 2002. It contains a variety of free-living and symbiotic forms, and also includes some important [[parasite]]s of humans.
Excavata is divided into several major groups, each with unique characteristics:
 
===Diplomonads===
[[Diplomonads]] are a group of flagellates, most of which are parasitic. They are characterized by having two nuclei and multiple flagella. A well-known example is ''[[Giardia lamblia]]'', a parasite that causes giardiasis in humans.
 
===Parabasalids===
[[Parabasalids]] are another group of flagellates, often found in symbiotic relationships with animals. They have a parabasal body, which is associated with the Golgi apparatus. ''[[Trichomonas vaginalis]]'', a cause of trichomoniasis, is a notable parabasalid.
 
===Euglenozoa===
[[Euglenozoa]] includes both free-living and parasitic species. Members of this group, such as ''[[Euglena]]'', are known for their photosynthetic capabilities, while others like ''[[Trypanosoma]]'' are notorious for causing diseases such as sleeping sickness.
 
==Ecological and Medical Importance==
Excavata play significant roles in various ecosystems and have important medical implications:


==Subgroups==
* '''Ecological Roles''': Many excavates are free-living and play crucial roles in aquatic ecosystems as primary producers and consumers.
Excavata is divided into several subgroups, including [[Diplomonadida]], [[Parabasalia]], and [[Euglenozoa]]. These groups are distinguished by their unique [[morphology]] and other cellular characteristics.
* '''Medical Importance''': Several excavates are pathogenic to humans, causing diseases such as giardiasis, trichomoniasis, and sleeping sickness.


==See also==
==Images==
[[File:Giardia_lamblia_SEM_8698_lores.jpg|thumb|left|''Giardia lamblia'', a diplomonad parasite.]]
[[File:Trypanosoma_sp._PHIL_613_lores.jpg|thumb|right|''Trypanosoma'', a genus of parasitic protozoa.]]
 
==Related pages==
* [[Eukaryote]]
* [[Protist]]
* [[Protist]]
* [[Eukaryote]]
* [[Flagellate]]
* [[Microorganism]]
* [[Parasitology]]
 
==References==
<references />


[[Category:Protista]]
[[Category:Excavata]]
[[Category:Excavata]]
{{stub}}
[[Category:Protists]]
<gallery>
[[Category:Eukaryotes]]
File:Excavata_cell_schemes.svg|Excavata
File:Two_Euglena.jpg|Euglena
File:TrypanosomaBrucei_ProcyclicTrypomastigote_SEM.jpg|Trypanosoma brucei
File:Bodo_saltans_-_400x_(13895749563).jpg|Bodo saltans
File:Percolomonas_sp.jpg|Percolomonas
File:Stephanopogon_sp.jpg|Stephanopogon
File:Naegleria_(formes)_en.png|Naegleria
File:Acrasis_rosea_31095.jpg|Acrasis rosea
File:Jakobida.svg|Jakobida
File:Trichomonas_Giemsa_DPDx.JPG|Trichomonas
File:Metamonada_retortamonas_hexamita_giardia.svg|Metamonada
File:Giardia_1.jpg|Giardia
</gallery>

Latest revision as of 17:32, 18 February 2025

A major supergroup of unicellular organisms



Excavata is a major supergroup of unicellular eukaryotic organisms, often characterized by a feeding groove "excavated" from one side. This group includes a variety of free-living and symbiotic forms, as well as some important human parasites.

Characteristics[edit]

Excavata are primarily distinguished by their unique cellular structure. Many members possess a distinctive "excavated" feeding groove, which is used to ingest food particles. This groove is a key feature that gives the group its name. Additionally, many excavates have flagella, which are used for locomotion and feeding.

Cell Structure[edit]

The cell structure of excavates is diverse, but they often share some common features:

  • Feeding Groove: A ventral feeding groove is present in many species, used for phagocytosis.
  • Flagella: Most excavates have one or more flagella, which are used for movement and feeding.
  • Mitochondria: The mitochondria in some excavates are highly modified or reduced, especially in anaerobic environments.

Classification[edit]

Excavata is divided into several major groups, each with unique characteristics:

Diplomonads[edit]

Diplomonads are a group of flagellates, most of which are parasitic. They are characterized by having two nuclei and multiple flagella. A well-known example is Giardia lamblia, a parasite that causes giardiasis in humans.

Parabasalids[edit]

Parabasalids are another group of flagellates, often found in symbiotic relationships with animals. They have a parabasal body, which is associated with the Golgi apparatus. Trichomonas vaginalis, a cause of trichomoniasis, is a notable parabasalid.

Euglenozoa[edit]

Euglenozoa includes both free-living and parasitic species. Members of this group, such as Euglena, are known for their photosynthetic capabilities, while others like Trypanosoma are notorious for causing diseases such as sleeping sickness.

Ecological and Medical Importance[edit]

Excavata play significant roles in various ecosystems and have important medical implications:

  • Ecological Roles: Many excavates are free-living and play crucial roles in aquatic ecosystems as primary producers and consumers.
  • Medical Importance: Several excavates are pathogenic to humans, causing diseases such as giardiasis, trichomoniasis, and sleeping sickness.

Images[edit]

Giardia lamblia, a diplomonad parasite.
Trypanosoma, a genus of parasitic protozoa.

Related pages[edit]