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Tadpoles are young amphibians that live in the water. During the tadpole stage of the amphibian life cycle, most [[respiration (physiology)|respire]] by means of autonomous external or internal [[gill]]s. They do not usually have arms or legs until the transition to adulthood, and typically have dorsal or fin-like appendages and a tail with which they swim by [[lateral undulation]], similar to most fishes.
Tadpoles are young amphibians that live in the water. During the tadpole stage of the amphibian life cycle, most [[respiration (physiology)|respire]] by means of autonomous external or internal [[gill]]s. They do not usually have arms or legs until the transition to adulthood, and typically have dorsal or fin-like appendages and a tail with which they swim by [[lateral undulation]], similar to most fishes.


As a tadpole matures, it most commonly [[Metamorphosis|metamorphosizes]] by gradually growing limbs (usually the legs first, followed by the arms) and then (most commonly in the case of frogs) outwardly absorbing its tail by [[apoptosis]]. Lungs develop around the time of leg development, and tadpoles late in development will often be found near the surface of the water, where they breathe air. During the final stages of external metamorphosis, the tadpole's mouth changes from a small, enclosed mouth at the front of the head to a large mouth the same width as the head. The intestines shorten to make way for the new diet.<ref>http://livingaquatic.com/product_info.php?products_id=85</ref> Tadpoles are consumers. Most tadpoles are herbivorous, subsisting on algae and plants. Some species are omnivorous, eating [[detritus]] and, when available, smaller tadpoles.<ref>http://www.nilesbio.com/print_catalog/index2.php</ref> However, other tadpoles are normally safe from cannibalistic predation because all tadpoles in a given body of water are the same age and, therefore, the same size.
As a tadpole matures, it most commonly [[Metamorphosis|metamorphosizes]] by gradually growing limbs (usually the legs first, followed by the arms) and then (most commonly in the case of frogs) outwardly absorbing its tail by [[apoptosis]]. Lungs develop around the time of leg development, and tadpoles late in development will often be found near the surface of the water, where they breathe air. During the final stages of external metamorphosis, the tadpole's mouth changes from a small, enclosed mouth at the front of the head to a large mouth the same width as the head. The intestines shorten to make way for the new diet.<ref>http://livingaquatic.com/product_info.php?products_id=85</ref> Tadpoles are consumers. Most tadpoles are herbivorous, subsisting on algae and plants. Some species are omnivorous, eating [[detritus]] and, when available, smaller tadpoles.<ref>http://www.nilesbio.com/print_catalog/index2.php</ref> However, other tadpoles are normally safe from cannibalistic predation because all tadpoles in a given body of water are the same age and, therefore, the same size. Sometimes tadpoles are also know to develop hair.


An exception to the rule of distinct differences between the tadpole (juvenile) and adult (frog, toad, salamander, etc.) stages is the [[axolotl]]. Axolotls exhibit a property called [[neoteny]], meaning that they reach [[sexual maturity]] without undergoing metamorphosis.
An exception to the rule of distinct differences between the tadpole (juvenile) and adult (frog, toad, salamander, etc.) stages is the [[axolotl]]. Axolotls exhibit a property called [[neoteny]], meaning that they reach [[sexual maturity]] without undergoing metamorphosis.
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Association
Association
50th Annual Meeting}}</ref> In Miocene fossils from Libros, Spain, the brain case is preserved in calcium carbonate, and the nerve cord in calcium phosphate. Other parts of the tadpoles' bodies exist as organic remains and bacterial biofilms, with sedimentary detritus present in the gut.<ref name=Mcnamara2009/> Tadpole remains with telltale external gills are also known from several of the [[Labyrinthodontia|Labyrinthodont]] groups.
50th Annual Meeting}}</ref> In Miocene fossils from Libros, Spain, the brain case is preserved in calcium carbonate, and the nerve cord in calcium phosphate. Other parts of the tadpoles' bodies exist as organic remains and bacterial biofilms, with sedimentary detritus present in the gut.<ref name=Mcnamara2009/> Tadpole remains with telltale external gills are also known from several of the [[Labyrinthodontia|Labyrinthodont]] groups.

==In popular fiction==
Tadpoles are common characters in children's cartoons. However, [[Wally the Tadpole]] got banned from some TV stations.


==References==
==References==

Revision as of 00:19, 26 October 2010

For other uses, see Tadpole (disambiguation).
Tadpoles

A tadpole, polliwog (also pollywog, polliwig, polwig, polispermie or purwiggy), or pollywiggle (also polliwiggle, polwiggle, or porwiggle) is the wholly aquatic larval stage in the life cycle of an amphibian, particularly of a frog or toad.

Appellation

The name "tadpole" is from Middle English taddepol, made up of the elements tadde, "toad", and pol, "head" (modern English "poll"). Similarly, "polliwog" and "pollywiggle" are from Middle English polwigle, made up of the same pol, "head" and wiglen, "to wiggle".

General description

Metamorphosis of Bufo bufo.
Tadpole stage of Haswell's Frog.

Tadpoles are young amphibians that live in the water. During the tadpole stage of the amphibian life cycle, most respire by means of autonomous external or internal gills. They do not usually have arms or legs until the transition to adulthood, and typically have dorsal or fin-like appendages and a tail with which they swim by lateral undulation, similar to most fishes.

As a tadpole matures, it most commonly metamorphosizes by gradually growing limbs (usually the legs first, followed by the arms) and then (most commonly in the case of frogs) outwardly absorbing its tail by apoptosis. Lungs develop around the time of leg development, and tadpoles late in development will often be found near the surface of the water, where they breathe air. During the final stages of external metamorphosis, the tadpole's mouth changes from a small, enclosed mouth at the front of the head to a large mouth the same width as the head. The intestines shorten to make way for the new diet.[1] Tadpoles are consumers. Most tadpoles are herbivorous, subsisting on algae and plants. Some species are omnivorous, eating detritus and, when available, smaller tadpoles.[2] However, other tadpoles are normally safe from cannibalistic predation because all tadpoles in a given body of water are the same age and, therefore, the same size. Sometimes tadpoles are also know to develop hair.

An exception to the rule of distinct differences between the tadpole (juvenile) and adult (frog, toad, salamander, etc.) stages is the axolotl. Axolotls exhibit a property called neoteny, meaning that they reach sexual maturity without undergoing metamorphosis.

Juvenile frog in transition between tadpole and frog

Fossil record

Remarkably, despite their soft-bodied nature and lack of mineralised hard parts, fossil tadpoles (around 10 cm in length) have been recovered from Upper Miocene strata.[3] They are preserved by virtue of biofilms, with more robust structures (the jaw & bones) preserved as a carbon film.[4] In Miocene fossils from Libros, Spain, the brain case is preserved in calcium carbonate, and the nerve cord in calcium phosphate. Other parts of the tadpoles' bodies exist as organic remains and bacterial biofilms, with sedimentary detritus present in the gut.[3] Tadpole remains with telltale external gills are also known from several of the Labyrinthodont groups.

Tadpoles are common characters in children's cartoons. However, Wally the Tadpole got banned from some TV stations.

References

  1. ^ http://livingaquatic.com/product_info.php?products_id=85
  2. ^ http://www.nilesbio.com/print_catalog/index2.php
  3. ^ a b Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1111/j.1502-3931.2009.00192.x, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1111/j.1502-3931.2009.00192.x instead.
  4. ^ Maria E. McNamara; Patrick J. Orr1, Stuart L. Kearns2, Luis Alcalá3, Pere Anadón4 and Enrique Peñalver-Mollá (2006). Taphonomy of exceptionally preserved tadpoles from the Miocene Libros fauna, Spain: ontogeny, ecology and mass mortality (PDF). The Palaeontological Association 50th Annual Meeting. {{cite conference}}: line feed character in |conference= at position 4 (help)CS1 maint: multiple names: authors list (link) CS1 maint: numeric names: authors list (link)

Media related to Tadpole at Wikimedia Commons The dictionary definition of tadpole at Wiktionary

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