World Library  
Flag as Inappropriate
Email this Article

Marine invertebrates

Article Id: WHEBN0015182882
Reproduction Date:

Title: Marine invertebrates  
Author: World Heritage Encyclopedia
Language: English
Subject: Charles Darwin, Marine larval ecology, Marine vertebrate, Permian–Triassic extinction event, Crustaceans/Selected biography/2
Collection:
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Marine invertebrates

The 49th plate from Ernst Haeckel's Kunstformen der Natur, 1904, showing various sea anemones classified as Actiniae, in the Cnidaria phylum

Marine invertebrates are all multicellular animals that inhabit a marine environment apart from the vertebrate members of the chordate phylum; invertebrates, lack a vertebral column. Some have evolved a shell or a hard exoskeleton.

As on land and in the air, invertebrates make up a great majority of all macroscopic life, as the vertebrates makes up a subphylum of one of over 30 known animal phyla, making the term almost meaningless for taxonomic purpose. Invertebrate sea life includes the following groups, some of which are phyla:

Ernst Haeckel's 96th plate, showing various invertebrates classified as Chaetopoda in the Annelida phylum
  • Myzostomida, a taxonomic group of small marine worms which are parasitic on crinoids or "sea lilies";
  • Nemertinea, also known as "ribbon worms" or "proboscis worms";
  • Orthonectida, a small phylum of poorly known parasites of marine invertebrates that are among the simplest of multi-cellular organisms;
  • Phoronida, a phylum of marine animals that filter-feed with a lophophore (a "crown" of tentacles), and build upright tubes of chitin to support and protect their soft bodies;
  • Placozoa, small, flattened, multicellular animals around 1 millimetre across and the simplest in structure. They have no regular outline, although the lower surface is somewhat concave, and the upper surface is always flattened;
  • Porifera (sponges), multicellular organisms that have bodies full of pores and channels allowing water to circulate through them;
  • Priapulida, or penis worms, are a phylum of marine worms that live marine mud. They are named for their extensible spiny proboscis, which, in some species, may have a shape like that of a human penis;
  • Pycnogonida, also called sea spiders, are unrelated to spiders, or even to arachnids which they resemble;
  • Sipunculida, also called peanut worms, is a group containing 144–320 species (estimates vary) of bilaterally symmetrical, unsegmented marine worms;
  • Tunicata, also known as sea squirts or sea pork, are filter feeders attached to rocks or similarly suitable surfaces on the ocean floor;
  • Some flatworms of the classes Turbellaria and Monogenea;
  • Xenoturbella, a genus of bilaterian animals that contains only two marine worm-like species;
  • Xiphosura, includes a large number of extinct lineages and only four recent species in the family Limulidae, which include the horseshoe crabs.

Minerals from sea water

There are a number of marine invertebrates that use minerals that are present in the sea in such minute quantities that they were undetectable until the advent of spectroscopy. Vanadium is concentrated by some tunicates for use in their blood cells to a level ten million times that of the surrounding seawater.[1] Other tunicates similarly concentrate niobium and tantalum.[1] Lobsters use copper in their respiratory pigment hemocyanin, despite the proportion of this metal in seawater being minute.[2] Although these elements are present in vast quantities in the ocean, their extraction by man is not economic.[3]

See also

References

  1. ^ a b
  2. ^
  3. ^
  • List of Animal Phyla
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 



Copyright © World Library Foundation. All rights reserved. eBooks from World eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.