Реферат на тему Frogs Essay Research Paper Frogs Frog is
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Frogs Essay, Research Paper
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.
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