|MadSci Network: Development|
That is a very good question. Some frogs, in fact DO give baby frogs, in a process called DIRECT DEVELOPMENT where there is no free swimming tadpole stage. Direct developing frogs can either be ovoviviparous or viviparous, depending if an egg is involved in the process or not. Oviparous means “egg-laying” (ovo means egg in Latin) and viviparous means “life-laying” (vida is life in Latin), ovoviviparous would me a mixture of both. Thus, the frogs can be subdivided according to their reproductive mode as: 1) oviparous:these are mostly aquatic, and because they live where water is abundant, their eggs will develop first in the swimming tadpoles that then metarmorphose into froglets. The Xenopus laevis (http://allaboutfrogs.org/info/species/clawed.html) is an example of oviparous frog. 2) ovoviviparous: These frogs will lay eggs that when hatched give out tiny small froglets (quite cute actually, in my opinion). Sometimes the eggs are not laid into the exterior environment, rather, the mother (and sometimes the father) will carry the eggs until gestation is over. An example of that would be the Golden Coqui from Puerto Rico (Eleutherodactylus jasperi: http://www.orecity.k12.or.us/ochs/departments/science/species/golden_ coqui.) html) Nourishment during the whole period is provided by the egg yolk. 3) viviparous: These are rare, and like mammals will produce live offspring, the young feed on oviductal secretions produced by the mother, but there is no placenta. Most of the viviparous amphibians are salamanders. Of the fogs, the African toad Nectophrynoides occidentalis is an example. So, I hope that this answers your question. Some frogs do actually start as baby frogs. If you wish to know more about the different species of frogs, try these different websites: http://allaboutfrogs.org/frog lnd.shtml This is a really fun sites with lots of frog facts http://la mar.colostate.edu/~packard/Teaching/Who'sWho.html A list with description of the amphibian families ht tp://www.csu.edu.au/faculty/commerce/account/frogs/brooding.htm This is a site about a frog in Australia that gives birth through the mouth! The baby froglets just crawl out of the mother’s mouth after 8 weeks of gestation.
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