Interesting facts about amphibians. Amazing Amphibians Tailless Amphibians Interesting Facts

Despite the fact that amphibians are distributed throughout the Earth, this is one of the few classes of animals that is practically not used by humans. Unless in the tropics (and in one of the European countries, whose inhabitants are called "frogs" for their addiction to frog legs), some types of amphibians are eaten, and biologists like to experiment on amphibians. Basically, amphibians and humans live on their own and rarely intersect.

A person's lack of mercantile interest in them does not make amphibians boring. Amphibians have their own characteristics, some of them are very interesting. In the selection below - teeth that are not chewed, a frog like a refrigerator, freezing newts, fireproof salamanders and other interesting facts.

1. All amphibians are predators. Even their larvae eat plant foods only at a young age, and then switch to live food. Of course, this is not from some kind of innate bloodthirstiness, it does not happen in nature. In the body of amphibians, the metabolism is very sluggish, so they can only survive on high-calorie animal food. Do not shun amphibians and cannibalism.

2. The teeth that some amphibians have are not designed for chewing prey. This is a tool for catching and capturing it. Amphibians swallow their food whole.

3. Absolutely all amphibians are cold-blooded. Therefore, the ambient temperature plays a crucial role for their survival.

4. The life of amphibians begins in the water, but most of it takes place on land. There are amphibians that live exclusively in the aquatic environment, but there are no reverse exceptions, there are only species that live only on trees in the humid jungle. So "amphibians" is a surprisingly accurate name.

5. However, even spending most of the time on land, amphibians are forced to constantly return to the water. Their skin is permeable to water, and if it is not moistened, the animal will die of dehydration. On their own, amphibians can secrete mucus to moisten their skin, but the resources of their organisms, of course, are not unlimited.

6. The permeability of the skin, which makes amphibians so vulnerable, helps them breathe normally. They have very weak lungs, so some of the necessary air is drawn into the body through the skin.

7. The number of amphibian species does not even reach 8 thousand (more precisely, there are about 7,700 of them), which is quite a bit for a whole class of living beings. At the same time, amphibians are very sensitive to the environment and do not adapt well to its changes. Therefore, environmentalists believe that up to a third of amphibian species are under threat of extinction.

8. Amphibians are the only class of creatures living on land whose offspring in their development passes through a special stage - metamorphosis. That is, not a reduced copy of an adult creature appears from a larva, but another organism, which subsequently turns into an adult. For example, tadpoles are frogs in the stage of metamorphosis. In the development of more complex organisms, there is no stage of metamorphosis.

9. Amphibians come from lobe-finned fish. They got out on land about 400 million years ago, and 80 million years ago they dominated the entire animal world. Before the dinosaurs came...

10. The reasons for the appearance of amphibians are still being explained purely hypothetically. It is believed that as a result of volcanic activity on Earth, the air temperature has risen, which has led to intensive grinding of water bodies. Reductions in the food supply for the inhabitants of the water and a drop in oxygen concentration led to the fact that some aquatic species died out, and some managed to get out onto land.

11. Amphibians also include worms - strange creatures that look like a cross between a worm and a snake. Worms live only in the tropics.

12. Dart frogs and leaf climbers are extremely poisonous. Rather, the mucus that they secrete to wet the skin is poisonous. One frog is enough for the South American Indians to make dozens of arrows poisonous. The lethal dose of poison for an adult is 2 milligrams.

13. Ordinary frogs, which are found in the reservoirs of central Russia, secrete mucus that has a bactericidal effect. A frog in a glass of milk is not a grandmother's fairy tale or a way to keep milk from being stolen. This is an ancient analogue of the refrigerator - frog mucus kills lactic acid bacteria and milk does not sour longer.

14. Newts belonging to amphibians are surprisingly resilient. They regenerate all parts of their body, even their eyes. A newt can dry out to the state of a mummy, but if water gets on it, it comes to life very quickly. In winter, newts easily freeze into the ice, and then thaw.

15. Salamanders are also amphibians. They prefer warmer weather conditions, and at the slightest cold snap they hide under branches, leaves, etc. and wait out the bad weather. Salamanders are poisonous, but their poison is not dangerous for humans - at most it can cause burning of the skin. However, it is still not worth testing your own susceptibility to salamander venom empirically.

16. Contrary to popular belief, the fire salamander is very much on fire. It's just that the layer of mucus on her skin is quite thick. It allows the amphibian to gain a few precious seconds to escape from the flames. The appearance of the name was facilitated not only by this fact, but also by the characteristic fiery coloring of the back of the fiery salamander.

17. Most amphibians are very good at navigating familiar terrain. And frogs are completely capable of returning to their native places even from afar.

18. Despite their low place in the hierarchy of animal classes, many amphibians see well, and some even distinguish colors. But such developed animals as dogs see the world in black and white.

19. Amphibians lay their eggs mainly in water, but there are species that bear eggs on their backs, in their mouths, and even in their stomachs.

20. Individuals of one of the salamander species grow up to 180 cm in length, which makes them the largest amphibians. And the tender meat makes giant salamanders an endangered species, salamander meat is so highly valued in China. The frogs of the Paedophryne species have the smallest size among amphibians, the average length of which is about 7.5 mm.

Types of frogs and their interesting features

Frogs are amphibians belonging to the order Anura (tailless). Below you will find some interesting facts about the life of these amazing amphibians.

The oldest fossils are believed to have evolved about 265 million years ago, they are called "protofrogs". These amphibians are widely distributed in subarctic and tropical regions, and there is a large population in tropical forests. Of all groups of vertebrates, they are the most diverse - 4800 species worldwide.

They are not so defenseless.

The adult is distinguished by a forked tongue, folded limbs, and a slippery body. These subtypes do not have a tail. Frogs are most commonly found in fresh water and irrigated lands and are thought to be highly adaptable to living underground or in trees.

They have a glandular type of skin, which in some species has embedded toxic glands, thus making them inedible. These animals are close relatives of toads. The skin color varies from grey, brown to green with a luminous pattern of yellow in some species.

Reproduction and nutritional features

These types of amphibians are known to lay their eggs in the water. In the dam, they hatch into larvae known as tadpoles, which have tails and gills. Frogs are divided into three types: herbivores, omnivores and carnivores. There are several subgroups that lay their eggs on land.

Adults are exclusively carnivorous and primarily consume small invertebrates. Omnivorous species, in addition, feed on fruits. As the breeding season begins, frogs tend to produce several kinds of sounds that reflect numerous complex behaviors, such as attracting the attention of a female for mating, scaring away predators.

More than one third of amphibian amphibians are believed to be globally threatened with extinction and their numbers are declining at an accelerating rate.

Let's find out something else interesting

Frogs have neither tail nor claws. They have complex leg structure, large eyes, shiny skin, extended ankle bones, and elongated hind legs. They have a short spine.

Their skin allows oxygen to easily pass through, so they can inhabit even places where there is no or very little oxygen, as they can breathe with their skin.

One of the main reasons for the population decline is that the frog's dermis is too vulnerable to the environment. They must keep their skin moist at all times, as there are poisonous substances in the air that can pass into the bloodstream and thus cause death.

External Features

The length of the amphibian ranges from 10 mm to 300 mm. Smaller species such as Brachycephalus didactylus can be found in Cuba and Brazil.

Their eyelid consists of three membranes, represented by connective tissue.

Unlike toads, frogs do have teeth, but they do not have teeth in the lower jaw, and amphibians mostly swallow their prey whole. With the help of their claws, frogs hold their prey tightly in order to swallow it completely.

Depending on belonging to one of the groups, they have different legs and feet. Tree-dwelling subspecies have different legs than terrestrial or burrow-dwelling species.

Agility

These animals must move quickly to catch their prey and also to evade natural predators.

The presence of webbing on the feet of a frog depends on the amount of time these species spend in water, compared to land.

The skin of an amphibian is able to absorb water and thus helps in maintaining body temperature.

Frogs are cold-blooded animals, so they can regulate their body temperature. Skin color is used for thermoregulation. It becomes darker as the temperature drops.

Disguise

Frogs, which tend to protect themselves with camouflage, are primarily nocturnal and hide during the day. There are several species that can change their skin color in order to evade predators.

The amphibian skin absorbs carbon dioxide and oxygen along with water, carrying them into the bloodstream. The skin contains a fairly large number of blood vessels, which allows oxygen to enter the body. On the ground, frogs use their lungs for breathing.

The teeth of amphibians are mainly used to absorb prey, which they then swallow. However, these teeth are not used for chewing prey, they are too weak for that.

Amphibians or amphibians are the most interesting animals that occupy an intermediate position between aquatic and terrestrial vertebrates. The origin of amphibians, their amazing way of life in both aquatic and terrestrial environments, their tadpole larvae, resembling more fish, and adult frogs that are not like them, the toxicity of some representatives of the class - these and many other features have always attracted the attention of scientists.

Amphibians came to land more than 200 million years ago. They were the first animals to come out of the water. Why did aquatic organisms have to come to land? Scientists have put forward a hypothesis that during this period of the development of the Earth, the land began to advance on the oceans. Water as a result of the volcanic activity of the Earth began to heat up and evaporate. Reservoirs became shallow, the density of their inhabitants increased, they became significantly depleted in oxygen and became unsuitable for life in them for animals that have only gills for breathing. In this regard, in some animals, in addition to gills, lungs also appeared. The fins began to resemble paws, with the help of which animals were able to get out onto land. And since the lungs were still underdeveloped, the skin took on a significant role in breathing. This is how the skin-pulmonary type of breathing appeared in amphibians.

The number of amphibian species and their distribution is quite extensive, despite the significant dependence on water bodies, which play an important role in their reproduction and lifestyle.

Biologists have counted the number of species of toads and frogs living on the globe. Tailless amphibians, for example, there are more than 6 thousand species. This is quite a lot, given their fertility.

Amphibians live most often near fresh water bodies. But there are also such as, for example, grass frogs, green toads, American northern toads and toad yeah (more about her), which can live and breed in salt water.

An adult frog is preceded by a larval stage. From the eggs laid in the pond, small tadpole larvae hatch, which are so called for their rather large head compared to the rest of the body. They bear little resemblance to adult frogs and rather resemble large-headed fish. They do not yet have limbs, and they breathe, like fish, with gills. After a while, paws appear; on the front - four fingers, and on the back - five. The fingers on the hind legs are connected by membranes and resemble the flippers of a swimmer. Or rather, people came up with flippers, watching how well frogs swim, pushing off the water with their hind legs. Gradually, the tadpoles lose their tail and become a copy of adult frogs, only they are still quite tiny. The gills are replaced by lungs, but the lungs in amphibians, even in adults, are very poorly developed, and thin skin rich in blood vessels plays the main role in the respiration of frogs.

The males of many frogs and toads have what are called resonators. In the spring, when it is already warm enough, frogs and toads arrange mating concerts, bursting into different voices, and these resonators increase the volume of the sounds made by the singers. Inflating rather large leathery bubbles on the sides of the head, they “sing”, attracting females.

In frogs and toads, the eyes not only perform a visual function, but also help in swallowing food. Having got a food object in their mouths, the frogs close their eyes, plunging them into the depths of the eye sockets. Looking at them at this moment, you might think that they are enjoying food, but in fact, the eyes of these amphibians perform the function of pushing food from the mouth into the throat at this time. By closing and pressing their eyes down, animals press the food with the underside of their eyes.

It is interesting to note that, contrary to previously accepted opinion, many frogs are able to distinguish colors. Toad frogs see all the main colors of the spectrum, the so-called disc-tongued frog does not distinguish between yellow, and the Japanese copepod does not see orange, yellow and green. The horned frog can only see red and blue. In general, as it turned out, amphibians are best able to distinguish between red and blue colors, perhaps because blue is the color of water and sky. Anyway, it's very interesting. After all, it is known that even such highly organized vertebrates as dogs do not distinguish colors.

Frogs have a peculiarly attached tongue. It is attached not like in other animals - to the inside of the oral cavity, but immediately behind the line of the lower lip, so that its end lies, on the contrary, almost at the entrance to the pharynx. Try, catch, for example, a fly from afar, if there is no special device for this, but the fly will not let you close, because it has excellent eyesight.

Amphibians, unlike mammals and reptiles, cannot chew their food. Their teeth are adapted only for grasping and holding writhing prey. In return, nature has endowed most amphibians with a long, sticky tongue that can capture prey with lightning speed.

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• The Latin name comes from the Greek amphíbios - living a double life.

• The class Amphibians totals more than 6700 (according to other sources - about 5000 modern species, which makes this class relatively few in number.

• In Russia, there are 28 species, and in the relatively small Madagascar - 247 species.

• The class Amphibians, among others, includes,.

• Amphibians are the first vertebrates to switch from an aquatic to an aquatic-terrestrial lifestyle.

• It belongs to the most primitive terrestrial vertebrates. Amphibians occupy an intermediate position between terrestrial and aquatic vertebrates.

• Reproduction in most species occurs in water.

• Amphibians, like, lay eggs, because. their eggs (caviar) and embryos are devoid of adaptations for terrestrial development. Development ends with Metamorphosis, during which the larvae lose their resemblance to fish and turn into adult animals.

• Adults live on land.

• The organization of amphibians as terrestrial vertebrates is imperfect in many respects: the intensity of metabolism is very low, the body temperature is unstable and corresponds to the temperature of the external environment.

• All amphibians have thin, smooth skin that is relatively easily permeable to gases and liquids. Moist and soft skin plays an important role in respiration in amphibians. The moisture of the skin, necessary for gas exchange, is maintained by the secretions of the mucous glands. In some species, the mucus can be poisonous.

• The skin is an additional organ for gas exchange and is equipped with a dense network of capillaries.

• All amphibians feed only on moving prey. At the bottom of the oropharyngeal cavity is the tongue. When catching, the tongue is thrown out of the mouth, prey sticks to it. The jaws have teeth that serve only to hold prey. In frogs, they are located only on the upper jaw.

• All modern amphibians are predators.

• The teeth serve only to grasp and hold the prey. At toads teeth are completely missing.

• There are no herbivorous animals among amphibians due to an extremely sluggish metabolism.

• Amphibians feed on small animals (mainly insects and invertebrates), and are prone to cannibalism. In aquatic species, juvenile fish may be included in the diet, and the largest prey on the chicks of waterfowl and small ones that have fallen into the water.

• In the life cycle of amphibians, four stages of development are clearly distinguished: egg, larva (tadpole), metamorphosis period, adult.

• For the development of an egg (caviar), its constant moisture is necessary. The vast majority of amphibians lay their eggs in fresh water, but there are known exceptions: giant salamanders, the amphibian frog and some other amphibians lay eggs on land. Eggs need even in these cases a high humidity environment, the provision of which falls on the parent.

• Species are known that carry eggs on their bodies: male midwife toads wrap a cord-like masonry around their hind legs, a female netted copepod frog attaches eggs to their stomach.

• The fertilized eggs of the Surinamese pipa are pressed by the male into the back of the female, and the latter carries it on herself until young pipas hatch from the eggs.

• The larvae that hatch from the eggs lead an aquatic lifestyle. They resemble fish in their structure: they do not have paired limbs, they breathe with gills (external, then internal). Only some species are already born in the form of small tailless frogs.

• The larvae undergo metamorphosis and turn into adults leading a terrestrial lifestyle.

• Amphibians of some species take care of their offspring (toad, tree frogs).

• Fossil amphibians are much more numerous and diverse than modern ones.

Extinct amphibians: 1 - Eogyrinus; 2 - Eryops; 3 - Gerrothorax; 4 - Seymouria; 5 - Metoposaurus; 6 - Ophiderpeton; 7 - Diplocaulus; 8 - Cardiocephalus.

• But modern amphibians are quite diverse and interesting:

Amphibians. 1 – ringed worm (Siphonops annulatus); 2 - Proteus (Proteus anguinus); 3 - red false newt (Pseudotriton ruber): 4 - fire salamander (Salamandra salamandra); 5 - common newt (Triturus vulgaris), female, 6 - male; 7 - Asia Minor newt (Triturus vittatus), female, 8 - male; 9 - axolotl - larva of ambistoma (Ambistoma tigrinum); 10 – Far Eastern toad (Bombina orientalis); 11 – tree frog (Hyla arborea).

Amphibians. 1 - spadefoot (Pelobates fuscus); 2 - slingshot (Ceratophrys cornuta); 3 - variable atelope (Atelopus varius); 4 - Venezuelan shorthead (Atelopus cruciger); 5 - South African narrowmouth (Breviceps adspersus); 6 - American frog (Rana pipiens); 7 – moored frog (Rana terrestris), male in nuptial plumage, 8 – male in regular plumage; 9 - green frog (Rana esculenta).

The decisive evolutionary link between water-dwelling fish and land mammals, as well as reptiles, are some of the most amazing animals on Earth -. In this article, you will discover 10 interesting facts about amphibians.

1. Amphibians live near water

The word "amphibian" means "double life", which pretty much sums up the peculiarity of these vertebrates: they lay their eggs in water and also need constant access to moisture to survive. Few amphibian species are in the middle of the evolutionary tree between the fully aquatic fish, terrestrial reptiles and mammals.

2. There are three main types of amphibians

Scientists divide amphibians into three main orders: tailless (frogs and toads), tailed (newts and salamanders) and legless (worms). At present, science knows about 6,000 species of frogs and toads, about 500 species of newts and salamanders, and less than 100 species of caecilians. All amphibians are technically classified as amphibians, but there are also two extinct groups of amphibians: thin vertebral and temnospondylic, some of which reached gigantic sizes during the late Paleozoic.

3. Most amphibians undergo metamorphosis

True to their evolutionary position (halfway between fish and fully terrestrial vertebrates), most amphibians are born from eggs laid in the water and spend a short period of life in the aquatic environment, equipped with external gills. Then, the larvae undergo a metamorphosis in which they shed their tails, overgrow their gills, grow strong legs, and develop primitive lungs in order to make their way to land at some point. The best-known larval stage is the frog tadpole, but the process of metamorphosis that occurs in them is less striking than in newts and salamanders.

4. Millions of years ago, amphibians dominated the Earth

For about 60 million years, from the beginning of the Carboniferous to the end of the Permian, amphibians were the dominant land animals on the planet, until they gave way to reptiles that developed from isolated amphibian populations, including archosaurs (ancestors of dinosaurs) and therapsids (ancestors of mammals). The classic representative of temnospondylic amphibians was the large-headed eriops, which had a body length of up to 2 meters.

5 Amphibians Have Permeable Skin

One of the reasons amphibians should stay near bodies of water is that they have thin, water-permeable skin. If they move too far from the water, they literally dry up and die. To help keep their skin moist, amphibians constantly secrete mucus (hence the reputation of frogs as "slippery" creatures), and their dermis is littered with glands that produce toxic substances meant to ward off predators. In most species, these toxins are barely noticeable, but some frogs are so venomous that they can kill an adult human.

6. Amphibians evolved from lobe-finned fish

During the Devonian period, about 400 million years ago, lobe-finned fish ventured onto land. They developed several key features: a musculoskeletal frame to support their body weight on land, as well as nostrils and leg bones, which became the impetus for subsequent evolution, during which, over several million years, the first primitive amphibians appeared, such as eukritta and crassigyrinus.

7. Like reptiles, amphibians are cold-blooded

A warm-blooded metabolism is generally reserved for more "advanced" vertebrates, so it's not surprising that amphibians are cold-blooded animals, warming up and cooling down according to ambient temperature. The advantage of cold-blooded animals is that warm-blooded animals need much more food to maintain their internal body temperature, but the main disadvantage is that they are limited in the ecosystem in which they can develop. Just a few degrees hotter or colder than their limit means imminent doom.

8 Amphibians Swallow Their Prey Whole

Unlike reptiles and mammals, amphibians do not have the ability to chew food. They have only a few teeth on the front top of their jaws, allowing them to hold writhing prey. Compensating for this shortcoming is that most amphibians have long, sticky tongues that they throw out at lightning speed to capture prey.

9 Amphibians Have Extremely Primitive Lungs

Much of the progress in vertebrate evolution goes hand in hand with the development of lung efficiency. Amphibian lungs have a relatively low internal volume, and are unable to process as much air as the lungs of reptiles and mammals. Fortunately, amphibians can absorb small amounts of oxygen through their permeable skin, which allows them to maintain their metabolic needs.

10. Amphibians are one of the most endangered animals in the world.

Their small size, permeable skin, and dependence on water make amphibians more vulnerable than most other animals and endangered. It is estimated that half of the planet's amphibian species are directly threatened by pollution and habitat destruction, invasive species, and even ozone depletion. Perhaps the biggest threat to frogs, salamanders and caecilians is chytrid fungi, which some experts attribute to global warming.