Tadpole
From Wikipedia, the free encyclopedia
A tadpole, polliwog (also pollywog, polliwig, polwig, or purwiggy), or pollywiggle (also polliwiggle, polwiggle, or porwiggle) is the wholly aquatic larval stage in the life cycle of an amphibian, particularly of an anuran.
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[edit] 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 and wiglen, "to wiggle".
[edit] General description
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 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] 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.
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.
[edit] Notes
[edit] External links
Media related to Tadpole at Wikimedia Commons
The Wiktionary definition of tadpole- Video of Hundreds of Tadpoles
- How to Raise Tadpoles
- Raising Tadpoles to Adulthood (University of California Berkeley)
