AY Honors/Life cycle of a frog

unidentified frog
A frog. (Click here to enlarge image)

A frog is a type of fresh-water amphibian of the Order Anura in the Class Amphibia. A frog is a vertebrate amphibian closely related to toads, also in the Order Anura. Most of the 4800 species of frogs spend their lives in or near a source of water (water frogs), although tree frogs live in moist environments that are not actually aquatic environments. The requirement for water becomes most acute for egg and tadpole stages of the frog, yet here again some species are able to utilize temporary pools and water collected in the axils of plants.

The life cycle of a frog involves several stages. A female frog lays her eggs in a shallow pond or creek, where they will be sheltered from the current and from predators. The eggs, known as frogspawn hatch into tadpoles, and this tadpole stage develops gradually into an adult frog. Typically, tadpoles are herbivores, feeding mostly on algae, whereas juvenile and adult frogs are rather voracious carnivores.

Many species of frog secrete toxins from their skin when under threat. These toxins deter predatory animals from eating them, and some are extremely poisonous to humans. The natives of the Amazon area extract curare from the poison arrow frog.

Green leopard frog

In many parts of the world the frog population has declined drastically over the last few decades, and in other areas, large numbers of frogs are born deformed due to unknown causes. Although pollution may be cited as a cause, the phenomenon has been observed in pristine mountain lakes and remains a mystery.

In 2003, Franky Bossuyt of the Free University of Brussels (Vrije Universiteit Brussel) and S.D. Biji of the Tropical Botanic Garden and Research Institute in Palode, India reported the discovery of a new species of frog so distinct in appearance and DNA that it merited its own new family, the first new family for frogs since 1926. This new species, dubbed Nasikabatrachus sahyadrensis, is dark purple in color, seven centimeters in length, and has a small head and a pointy snout. Genetically, it's closest living relatives are the sooglossids found in the Seychelles. The new species was discovered in the Sahyadri (Western Ghats) Mountains in India.

External links

• The Whole Frog Project ~ (virtual frog dissection and anatomy)
• Frog Info Pool
• Disappearance of toads, frogs has some scientists worried ~ San Francisco Chronicle, April 20, 1992
• The Froggy Page ~ Frog fun

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Other Frogs

• A frog in sewing is a sort of closure, often used in cloaks, made from a specially knotted cord forming a button of sorts, and a loop on the other side of the closure, forming an effective button hole.
• One of the most famous frogs in the entertainment world is the Muppet character Kermit the Frog (not easy being green indeed).
• In Australia the Freddo frog is a popular confectionery treat.
• The American TV network The WB (Warner Brothers) uses a frog in a tuxedo as their logo.