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'''Echinoderm''' is a phylum of marine animals found at various depths in the oceans. The phylum includes starfish, sea urchins, sand dollars, and sea cucumbers. Echinoderms are characterized by radial symmetry, a water vascular system, and a calcareous endoskeleton.
{{Short description|A detailed overview of echinoderms, a phylum of marine animals}}


== Characteristics ==
==Echinoderm Overview==
[[File:Starfish.jpg|thumb|right|A starfish, a common type of echinoderm.]]
Echinoderms are a diverse and fascinating group of marine animals belonging to the phylum [[Echinodermata]]. This phylum is characterized by its members' unique radial symmetry, a calcareous endoskeleton, and a water vascular system. Echinoderms are exclusively marine and are found in oceans all over the world, from the intertidal zone to the deep sea.


Echinoderms are unique among animals in having a [[water vascular system]], which is a network of hydraulic canals branching into extensions called tube feet. These tube feet function in locomotion, feeding, and respiration.
==Characteristics==
Echinoderms exhibit several distinctive features:


Echinoderms also possess a [[calcareous endoskeleton]] that consists of plates or ossicles. These ossicles may be fused together, as in sea urchins, or articulated, as in sea stars.
* '''Radial Symmetry''': Most adult echinoderms have a five-part radial symmetry, although their larvae are bilaterally symmetrical.
* '''Endoskeleton''': Composed of calcareous plates or ossicles, the endoskeleton provides support and protection.
* '''Water Vascular System''': This hydraulic system is unique to echinoderms and is used for locomotion, feeding, and respiration. It includes tube feet, which are extensions that can be extended or retracted by hydraulic pressure.
* '''Regeneration''': Many echinoderms have remarkable regenerative abilities, allowing them to regrow lost arms or other body parts.


== Classification ==
==Classification==
The phylum Echinodermata is divided into several classes:


The phylum Echinodermata is divided into five extant classes:
* '''[[Asteroidea]]''': This class includes starfish or sea stars, which are perhaps the most well-known echinoderms.
* '''[[Ophiuroidea]]''': Brittle stars and basket stars belong to this class, characterized by their distinct central disc and long, flexible arms.
* '''[[Echinoidea]]''': Sea urchins and sand dollars are part of this class, known for their spiny exteriors.
* '''[[Holothuroidea]]''': Sea cucumbers are included in this class, notable for their elongated bodies and leathery skin.
* '''[[Crinoidea]]''': This class includes sea lilies and feather stars, which have feathery arms used for filter feeding.


* [[Asteroidea]] (starfish or sea stars)
==Ecology and Habitat==
* [[Ophiuroidea]] (brittle stars)
[[File:Sea_urchin.jpg|thumb|left|A sea urchin, another type of echinoderm.]]
* [[Echinoidea]] (sea urchins and sand dollars)
Echinoderms play a crucial role in marine ecosystems. They are often found on the ocean floor, where they contribute to the benthic community. Many echinoderms are detritivores, feeding on decaying organic matter, while others are predators or filter feeders.
* [[Crinoidea]] (sea lilies and feather stars)
* [[Holothuroidea]] (sea cucumbers)


== Ecology and life history ==
Echinoderms are also important in the food chain, serving as prey for a variety of marine animals, including fish, sea otters, and birds. Their presence can indicate the health of marine environments, as they are sensitive to changes in water quality and temperature.


Echinoderms are exclusively marine and are found at every ocean depth. They play important roles in marine, benthic ecosystems. Many echinoderms are suspension feeders that capture plankton and detritus from the water column.
==Reproduction==
Echinoderms have diverse reproductive strategies. Most species are dioecious, with separate male and female individuals, although some are hermaphroditic. Fertilization is typically external, with eggs and sperm released into the water column. The resulting larvae are planktonic and undergo several developmental stages before settling to the ocean floor and transforming into adults.


Echinoderms have a variety of reproductive strategies. Most species are dioecious and have external fertilization, but some species are hermaphroditic or have internal fertilization.
==Evolutionary Significance==
 
Echinoderms are an ancient group, with a fossil record dating back to the Cambrian period. Their unique body plan and evolutionary adaptations provide valuable insights into the evolution of deuterostomes, a superphylum that also includes chordates.
== Evolution ==
 
The echinoderms are an ancient group, with fossils dating back to the [[Cambrian period]]. They have undergone significant evolutionary changes, including a shift from bilateral to radial symmetry.
 
== See also ==


==Related Pages==
* [[Marine biology]]
* [[Marine biology]]
* [[Invertebrate zoology]]
* [[Invertebrate]]
 
* [[Oceanography]]
== References ==
* [[Benthic zone]]
 
<references />


[[Category:Echinoderms]]
[[Category:Marine biology]]
[[Category:Marine biology]]
[[Category:Invertebrates]]
[[Category:Echinoderms]]
{{stub}}
== Echinoderm ==
<gallery>
File:Echinoderm_collage_2.jpg|Echinoderm
File:Ophionereis_reticulata_1.jpg|Ophionereis reticulata
File:Sea_cucumber_at_Pulau_Redang.jpg|Sea cucumber at Pulau Redang
File:Nerr0878.jpg|Echinoderm
File:Strongylocentrotus_purpuratus_1.jpg|Strongylocentrotus purpuratus
File:Crinoid_on_the_reef_of_Batu_Moncho_Island.JPG|Crinoid on the reef of Batu Moncho Island
File:FMIB_52615_Diagram_of_water-vascular_system_of_a_starfish_;.jpeg|Diagram of water-vascular system of a starfish
File:Sea_star_regenerating_legs.jpg|Sea star regenerating legs
File:Comet_form_of_Linckia.png|Comet form of Linckia
File:Pluteus001.jpg|Pluteus
File:Podia_de_Colobocentrotus_atratus.JPG|Podia de Colobocentrotus atratus
File:Neothyonidium_magnum_(Burrowing_sea_cucumber).jpg|Neothyonidium magnum (Burrowing sea cucumber)
</gallery>
<gallery>
File:Echinoderm_collage_2.jpg|Echinoderm
File:Ophionereis_reticulata_1.jpg|Ophionereis reticulata
File:Sea_cucumber_at_Pulau_Redang.jpg|Sea cucumber at Pulau Redang
File:Nerr0878.jpg|Echinoderm
File:Strongylocentrotus_purpuratus_1.jpg|Strongylocentrotus purpuratus
File:Crinoid_on_the_reef_of_Batu_Moncho_Island.JPG|Crinoid on the reef of Batu Moncho Island
File:FMIB_52615_Diagram_of_water-vascular_system_of_a_starfish_;.jpeg|Diagram of water-vascular system of a starfish
File:Sea_star_regenerating_legs.jpg|Sea star regenerating legs
File:Comet_form_of_Linckia.png|Comet form of Linckia
File:Pluteus001.jpg|Pluteus
File:Podia_de_Colobocentrotus_atratus.JPG|Podia de Colobocentrotus atratus
File:Neothyonidium_magnum_(Burrowing_sea_cucumber).jpg|Neothyonidium magnum (Burrowing sea cucumber)
</gallery>

Latest revision as of 17:32, 18 February 2025

A detailed overview of echinoderms, a phylum of marine animals


Echinoderm Overview[edit]

File:Starfish.jpg
A starfish, a common type of echinoderm.

Echinoderms are a diverse and fascinating group of marine animals belonging to the phylum Echinodermata. This phylum is characterized by its members' unique radial symmetry, a calcareous endoskeleton, and a water vascular system. Echinoderms are exclusively marine and are found in oceans all over the world, from the intertidal zone to the deep sea.

Characteristics[edit]

Echinoderms exhibit several distinctive features:

  • Radial Symmetry: Most adult echinoderms have a five-part radial symmetry, although their larvae are bilaterally symmetrical.
  • Endoskeleton: Composed of calcareous plates or ossicles, the endoskeleton provides support and protection.
  • Water Vascular System: This hydraulic system is unique to echinoderms and is used for locomotion, feeding, and respiration. It includes tube feet, which are extensions that can be extended or retracted by hydraulic pressure.
  • Regeneration: Many echinoderms have remarkable regenerative abilities, allowing them to regrow lost arms or other body parts.

Classification[edit]

The phylum Echinodermata is divided into several classes:

  • Asteroidea: This class includes starfish or sea stars, which are perhaps the most well-known echinoderms.
  • Ophiuroidea: Brittle stars and basket stars belong to this class, characterized by their distinct central disc and long, flexible arms.
  • Echinoidea: Sea urchins and sand dollars are part of this class, known for their spiny exteriors.
  • Holothuroidea: Sea cucumbers are included in this class, notable for their elongated bodies and leathery skin.
  • Crinoidea: This class includes sea lilies and feather stars, which have feathery arms used for filter feeding.

Ecology and Habitat[edit]

File:Sea urchin.jpg
A sea urchin, another type of echinoderm.

Echinoderms play a crucial role in marine ecosystems. They are often found on the ocean floor, where they contribute to the benthic community. Many echinoderms are detritivores, feeding on decaying organic matter, while others are predators or filter feeders.

Echinoderms are also important in the food chain, serving as prey for a variety of marine animals, including fish, sea otters, and birds. Their presence can indicate the health of marine environments, as they are sensitive to changes in water quality and temperature.

Reproduction[edit]

Echinoderms have diverse reproductive strategies. Most species are dioecious, with separate male and female individuals, although some are hermaphroditic. Fertilization is typically external, with eggs and sperm released into the water column. The resulting larvae are planktonic and undergo several developmental stages before settling to the ocean floor and transforming into adults.

Evolutionary Significance[edit]

Echinoderms are an ancient group, with a fossil record dating back to the Cambrian period. Their unique body plan and evolutionary adaptations provide valuable insights into the evolution of deuterostomes, a superphylum that also includes chordates.

Related Pages[edit]