Essay/Term paper: Frogs

Essay, term paper, research paper:  Science Reports

Frogs


Frog is the common name for a species of amphibian that also includes
toads. A very common question is "whats the difference between frogs and toads?"
, the answer: none, except for the fact that toads lack the powerful legs that
frogs have. "Where can frogs and toads be found?", one might ask. They live in
all parts of the world, except for Antarctica, but are mostly found in tropical
areas. Frogs are small animals with smooth moist skin, and big eyes that can
see in almost any direction. Most species have webbed feet and powerful legs
making them good jumpers, and excellent swimmers. A frogs tongue is attached to
the front of it"s mouth instead of the rear, and most frogs are very vocal,
especially the male frogs.
As a frog grow, it goes through many changes. Starting out as a tadpole,
and morphing into a frog. Most frogs lay their eggs in water. Others will lay
their eggs some where safe, then carry them to water where they hatch into
tadpoles. At this stage they have gills, no legs, and a tail. As they mature,
their gills and tail disappear, and they develop lungs and legs. This period of
tadpole life can be divided into three stages. The first stage, called "
premetamorphosis," lasts about 50 days (Patent 54). The second stage, in which
the hind legs grow, is called "prometamorphosis," and lasts about 21 days. When
the legs are about as long as the body, the third stage, which is called "
metamorphic climax," and takes place very rapidly, begins. During this last
stage, which lasts about a week, many great changes occur. They lungs complete
their development, and the gills disappear. The skin gets thicker, nostrils
form, and the tail is completely resorbed.
Most frogs prefer moist regions, and many kinds live in the water.
Because frogs absorb oxygen in water through their skin, they can stay
underwater for long periods of time. A frogs body temperature depends on it"s
surroundings, and during cold weather, frogs dig burrows in mud and hibernate.
During hibernation, the frog needs little oxygen and no more food than is
already in it"s tissues. During intense heat, a frog might estivate, or in
other words, lie in a state of torpor during the heat, after burying themselves
in sand and clay.
Frogs are carnivores. They eat just about anything smaller than then
that moves. A frog thinks like this: If it"s smaller than itself and moves,
eat it. If it"s the same size, mate, or attempt to mate (this gets some frogs
in lots of trouble). If it"s bigger than itself, run. Their diet may include
insects, worms, spiders, or even centipedes. Aquatic frogs sometimes eat other
frogs, tadpoles, and small fish. Large frogs can eat can eat stuff as big as
mice and snakes. Sometimes a frog eats something too big to swallow all at once,
and will leave it sticking out of its mouth ingesting it gradually or even
choking and regurgitating it. So virtually, the size of a frog"s dinner is
determined by the size of it"s mouth. If a frog eats something poisonous or bad
for them, they can throw up their entire stomach and wipe it with their right
front leg.
Frogs help out humans in many ways. Toads are used world wide as pest
control in gardens and on farms. One toad alone can consume thousands of insects.
Frogs have been used as food for centuries. Efforts have been made to harvest
frogs, but most frogs eaten today are taken from their natural habitat. People
in South America, the South Pacific, Philippine Islands, and parts of Africa
savor frogs, and consider them a delicacy. The Chinese and French are lovers of
frogs legs. One of the reasons frogs legs are so expensive is the great demand
for frogs in scientific and medical laboratories. Because their skeletal,
muscular, digestive, nervous, and other systems are similar to those of higher
animals, frogs are very important in these in these fields of research.
One large and nearly worldwide family of frogs are the true frogs, many
species combined that are well known (Encarta True Frogs). The Bullfrog is one
of the largest true frogs in North America (Barker 150). It weighs up to 1.2
pounds and has a total length of 15 inches. One of the most common North
American species is the leopard frog (Barker 154), which is easily recognized by
the numerous black, often light-edged spots on the back and legs. Most true
frogs stay close to ponds and streams, but the North American wood frog
(Stebbins 135), a small redish-brown species with mask-like black bands on the
head, wander far away from the water. The green frog is another common species
in North America and despite their name, some green frogs are brown. Two well-
known true frogs of Europe are the common European frog, which resembles the
wood frog, and the edible frog, a popular food in Europe. The African Giant
Frog, the largest of all frogs, which grows as long as 26 inches and weighs as
much as 10 pounds, is also a true frog . The smallest frog is probably the
Psyllophyne Didactyla from Brazil which is about 9.8 mm as an adult.
The frogs and other amphibians of North America, and those of other
continents too, are important in the way all wild things are important. They
are also a living resource that needs protection and greater understanding to
appreciate its true worth.
Today there is a strong effort by all forms of government to set aside
areas that furnish the sort of environments required by many forms of wildlife,
including frogs. Private organizations and individuals too have established
many special areas mostly free from conditions that disturb natural habitats.
People are finally realizing that, hey, frogs aren"t such bad guys and maybe we
should keep them around.