Almost all of us think that we are no problems we can define any notion of a comprehensive school program.For example, amphibians - a frog, turtles, crocodiles and the like flora.Yes, it is true.To name some representatives we are able, but what about the description of the characteristics or lifestyle?Somehow, they also identified in a special class?What is the reason?And what is the pattern?But with this, you see, is more complicated.
What are we surprised?
It is likely that the respiratory system is different from amphibians like the internal device, for example, mammals or reptiles.But what?Are there similarities between us and them?To all these questions we try to answer in this article.However, you should pay attention to the fact that in the process of studying the material the reader will not only learn about what is similar to each other reptiles (turtles and crocodiles to him, by the way, do not apply), but also to get acquainted with the most interesting facts connected with the dataanimals.I bet that about something you were not even aware.Why is that?The fact is that the section of the school textbook does not always provide all the necessary range of knowledge.
General information about the class
Class Amphibians (or amphibians) is a primitive vertebrate ancestors more than 360 million years ago, we have changed the habitat and out of the water onto land.In a translation from Greek name means "living a double life."
It should be noted that amphibians - cold-blooded creatures is a non-constant body temperature, which depends on external environmental conditions.
In the warmer months, they tend to be active, but in cold weather hibernate.There are amphibians (frogs, newts, salamanders) in the water, but the major part of its existence, carried out on land.This feature can be called almost the basic life of the species of living beings.
amphibians
In general this class of animals is more than 3,000 species of amphibians, represented by three groups:
- tailed (Newt);
- tailless (frogs);
- legless (caecilians).
amphibians appeared in temperate and tropical climates.However, to this day they live there.
basically all small size and have a length of one meter.An exception is the giant salamander (main characteristics of amphibians as if she greased), who lives in Japan and reach a length of up to six meters.
amphibians spend his life alone.Scientists have found that it was not the result of evolution.The first amphibians were exactly the same lifestyle.
Among other things, they are perfectly camouflaged by changing its color.By the way, not everyone knows that the protection from predators is also a poison secreted by special glands of skin.Perhaps such a feature have only reptiles, arthropods and amphibians.Mammals with a set of unique features not found in nature.In fact, hard to imagine, for example, familiar to all of us cat could adjust the temperature of his body in response to changes in the environment or release poison defending against attacks her dog.
Features skin
All amphibians have a smooth thin cover leather, rich skin glands that produce mucus is necessary for gas exchange.
mucus also protects the skin from drying out and can contain toxic substances or signal.Stratified epidermis richly equipped with a network of capillaries.Most venomous species can take bright colors, serving as a protective device and a warning to predators.
Some tailless amphibians group on the upper layer of the epidermis horny meet education.It is especially developed in toads that have more than half of the skin surface is covered with a horny layer.Importantly, weak keratinization cover does not hinder the penetration of water through the skin.Thus arranged breathing amphibians, which are able to breathe underwater just skin.
in terrestrial species keratinized skin can form on the legs claws.In tailless amphibians all the subcutaneous space occupied by the lymphatic lacunae - cavity where the accumulated water reserve.And only in a few places the connective tissue of the skin is connected to the muscles amphibians.
Lifestyle amphibians
Amphibians, photos of which can be found in all the books on zoology, undergo several stages of development: born in the water and having a resemblance to the fish as a result of the conversion of acquired pulmonary respiration and the ability habitat on land.
This development is not found in other vertebrates, but is common in primitive invertebrates.
They occupy an intermediate position between the water and land vertebrates.They live amphibians (fish in this respect are more suited representatives of fauna) in all parts of the world where water is freshwater, except for cold countries.Most of these half-life is carried out in water.Other adults live on land, but in places with high humidity and near water.
During drought amphibians (bird would envy such a feature) hibernate buried in the mud, and in the cold in temperate zones exposed hibernation.
most favorable habitats are tropical countries with rainforests.Least of all amphibians prefer arid corners of nature (Middle Asia, Australia, and so on. D.).
This ground-water dwellers, preferring usually nocturnal.Day conducted in a shelter or in a half-asleep.Tailed kinds of moves on the ground similar to the creeping things, and tailless - short hops.
Amphibians - are animals that, as a rule, are able to climb trees.Unlike reptiles, amphibians, adult males are very vociferous in his youth are soundless.
Power in most cases depends on the age and stage of development.The larvae feed on plant and animal organisms.As they get older there is a need for live food.This is the real predators, feeding on worms, insects and small vertebrates.During heat their appetite increases.The inhabitants of the tropics much more voracious than their relatives from temperate countries.
In the early life of amphibians, whose photos adorn atlases, clearly showing the evolution of man, evolve rapidly, but eventually their growth slows to a crawl.Height frogs extends to 10 years, although the maturity reached by the 4-5 years.In other species stops growing only to 30 years.
In general, it should be noted that amphibians - this is a very hardy animal that can endure hunger better than reptiles.For example, a toad, planted in a damp place, may be without food for up to two years.Respiratory system amphibians while still fully operational.
amphibians also possess the ability to regenerate lost body parts.However, highly amphibians such properties are less pronounced or non-existent.
Like reptiles, amphibians are also quickly heal wounds.Special survivability differ tailed species.If a salamander or newt frozen water, they fall into a stupor and become brittle.As soon as the ice melts, the animals back to life again.It is necessary to remove the newt out of the water, it immediately shrinks and no signs of life.Put it back - and Triton immediately revives.
body shape and structure similar to a skeleton fish.The brain consists of two hemispheres, cerebellum and midbrain, and has a simple structure.The spinal cord is more developed than the head.Teeth amphibians serve only to capture and hold prey, but not suited for chewing it.Of great importance for the life of amphibians have respiratory and circulatory systems.They, like a reptile, cold blood.
In appearance and way of life of amphibians (turtles, recall, they do not include, though sometimes lead a similar lifestyle) are divided into three groups: tailless, tailed and legless.The representatives include tailless frogs, which are spread all over the world where there is enough moisture and food.Frogs like to sit on the beach and bask in the sun.At the slightest danger, they throw themselves into the water and bury themselves in the mud.
representatives such a huge group of animals, amphibians as a class, are good swimmers.With the approach of cold weather amphibians hibernate.Spawning occurs in the warmer months.Development of eggs and tadpoles quickly.Their main food is plant and animal foods.
tailed amphibians like the lizards.They live in ponds or near water.They are nocturnal and hide during the day in shelters.Unlike lizards on land, they are slow and clumsy, but the water is very agile.They feed on small fish, molluscs, insects and other small animals.In this type include salamanders, newts, Proteus, giant salamander, and so on. D.
the squad legless amphibians are caecilians, which have resemblance to snakes and legless lizards.However, the development and internal structure are close to the salamanders and proteome.Caecilians live in tropical countries (except Madagascar and Australia).They live underground, burrowing.Lead the same lifestyle as the earthworms that constitute their diet.Some caecilians bring viviparous offspring.Other lay eggs in the soil near the water or in the water.
Benefits amphibians
Amphibians are the first and most primitive inhabitants of the land, occupies a special place in the evolution of terrestrial vertebrates, which is the least studied.
For example, the role of birds and mammals in human life has long been known.In this respect, amphibians are very far behind.However, they are also important in human activities.As is known, in many countries, frog legs are a delicacy highly prized.For these purposes, in Europe and North America annually produces about one hundred million frogs.This indicates that amphibians have economic importance.
Adults feed on animal food.Eating insect pests in gardens, orchards and fields, they benefit humans.Among insects, mollusks and worms are also found dangerous carriers of various diseases.
considered less useful amphibians that feed on aquatic organisms.Exceptions are the newts.Although the basis of their food consists of aquatic organisms, they also eat mosquito larvae (in Vol. H. Of malaria) that breed in ponds with a warm and stagnant water.
Benefits amphibians in many respects depends on the number of seasonal, feed and other features.All these factors affect the power of amphibians.For example, the marsh frog that lives in ponds, healthier than her relatives living elsewhere.
Unlike birds, amphibians consume a greater number of insects possessing deterrent and security features that do not eat birds.Also, terrestrial species of amphibians feed mostly at night, when many insectivorous birds sleep.
full significance of amphibians in a person's life can only be assessed with sufficient study of these animals.Currently, biology of amphibians have very superficial knowledge.
Amphibians are an important part of the food chain
Some fur animals, most amphibians are the main food.For example, the survival of a raccoon dog in different habitats depends on the number of amphibians in these areas.
mink, otter, badger and polecat willingly eat amphibians.Therefore, the number of these animals important for hunting grounds.Amphibians are included in the diet and other predators.Especially when you do not have enough basic food - small rodents.
addition, valuable commercial fish in the winter in ponds and rivers feed the frogs.Most often their prey becomes grass frog, which, in contrast to the green frog, not buried in the mud for the winter.In summer it feeds on terrestrial invertebrates, in winter goes in the winter in the lake.Thus, amphibian becomes an intermediary and replenishes the food base for fish.
Amphibians and science
Due to its structure and vitality of amphibians have been used as laboratory animals.It is a frog held the largest number of experiments ranging from biology lessons at school and to large medical research scientists.For these purposes, as a biological material in laboratories used annually over tens of thousands of frogs.It is possible that this could lead to the complete destruction of the animals.By the way, catching frogs in England banned and they are now under protection.
is difficult to enumerate all the scientific discoveries related to the experiences and physiological experiments on frogs.It was recently found their application in laboratory and clinical practice for early diagnosis of pregnancy.The introduction of the urine of pregnant women in male frogs and toads gives them a rapid process of spermatogenesis.In this respect it stands out the green toad.
most unusual amphibians planet
Among poorly studied species of these animals found many rare and unusual specimens.
example, ghost frog (born Heleophryne) - it is in fact a unique family of tailless amphibians with only six species, one of which is found only in the cemetery.Apparently, here and there is a rather unusual name of the species.They live mainly in the north-east of South Africa, near the forest streams.Have a size of up to 5 cm and camouflage coloring.They are nocturnal and hide under rocks at night.However, to date, two species almost exterminated.
Proteus (Proteus anguinus) - tailed amphibians kind of class, living in underground lakes.It reaches a length of 30 cm. All individuals are blind and have clear skin.Proteus hunt through electrical sensitivity of the skin and sense of smell.Can live without food for up to 10 years.
next representative, frog zooglossus Gardner (Sooglossus gardineri) refers to one of the most unusual species of tailless amphibians.It is under threat of destruction.It has a length less than 11 mm.
Frog Darwin's - it is a small tailless amphibian, living in cold mountain lakes.The body length of about 3 cm. The males are hatching their offspring in the throat bag.
Interesting facts about amphibians
- Even far from all avid travelers know that the State of Peru many cafes, which serves special cocktails of frogs.It is believed that such drinks relieve many illnesses, treat asthma and bronchitis, help restore potency.One way to prepare is grinding live frog in a blender with the addition of bean soup, honey, aloe juice and poppy root.Are you ready to venture out and try this dish?
- unusual amphibians live in South America.Paradoxical frog as they mature are reduced in size.The usual length of adult reaches only 6 cm. However, their tadpoles grow up to 25 cm. A strange feature.
- During laboratory experiments on frogs, Australian researchers have made an accidental discovery.They found that these animals are able to remove foreign bodies from its body through the bladder.Experienced and very eminent scientists implanted animals transmitters that after some time moved into their bladders.Thus, it turned out that getting into the body of amphibians, foreign objects gradually become overgrown with soft tissue and are drawn into the bubble.This discovery actually made a revolution in science.
- Few of ordinary people aware of the fact that the cause of frequent blinking while eating frogs is pushing food into the throat.Animals are not able to chew food and pushing his tongue into the esophagus.Blinking eyes are drawn into a skull with special muscles and help push the food.
- very interesting instance is the African frog Trichobatrachus robustus, which has an amazing device for protection against enemies.At the time of the threat legs pierced subcutaneous bone, forming a kind of "claws."
