Anurans are animals belonging to the class Amphibia, the adult body is basically tailless, the eggs are usually laid in the water and hatch into tadpoles, which breathe with their gills, and after metamorphosis, the adult body mainly breathes with its lungs, but most of the skin also has a partial respiratory function. Two main groups of animals are included: frogs and toads. There is no strict distinction between these two groups of animals, and some include both in one family. Generally speaking, toads tend to live on land and therefore have rough skin, while frogs are slimmer and more adept swimmers. Both species have similar body shapes, with inconspicuous necks and no ribs. The ulna of the forelimb is fused with the radius, and the tibia of the hindlimb is fused with the fibula, so the claws can't rotate flexibly, but the limbs are well-muscled.
The anurans are the first step of organisms to go from water to land, and are more advanced than the other amphibians, although most can already live out of water, reproduction is still not possible without water, and the eggs need to undergo metamorphosis in the water in order to grow. Therefore less advanced than reptiles, which can already live completely out of water.
Frogs: There are about 4,800 species of frogs, most of which live in the water, but some live in the trees in the wet environment of the rainforest. Eggs are laid in water, but some tree frogs can pass through the tadpole stage simply by using puddles of water that accumulate in holes in trees or at the roots of plant leaves. 2003 saw the discovery of a new species of "purple frog" in western India, which lives year-round in holes in the ground and only emerges from its hole to give birth to babies when the monsoons bring rain.
It is difficult to make an absolute distinction between frogs and toads, and some families, such as the Discoglossidae, include both frogs and toads.
The smallest frogs are only 50 millimeters, equivalent to a person's thumb, the large 300 millimeters (more than a foot long), pupils are transverse, smooth skin, tongue bifurcated, tongue heel in the front of the mouth, inverted long back into the mouth, can be suddenly flipped out to catch bugs. There are three eyelids, one of which is transparent and used to protect the eyes under water, and the other two upper and lower eyelids are plain. There are two vocal sacs on either side of the head that produce **** calls and amplify the call. Smaller breeds have a higher frequency of calls.
Some frogs secrete venom from their skin to protect against predators, and the secretions of a tree frog living in the rainforests of the Amazon River basin were used by local Indians to make arrow venom, which bleeds at the sight of blood.
The frogs are found throughout the world, except for the Caribbean and Pacific islands. However, they are currently declining rapidly worldwide, mainly due to environmental pollution, climate change, invasion of exotic species, and shrinking habitats due to human expansion.
Frogs reproduce in a way similar to toads, and also feed on insects, but large frogs can hunt small fish and even mice. Basically, they hunt at night.
The frog preys on a large number of field pests and is a beneficial animal to humans. It is not only the natural enemy of pests and the guardian of the harvest. The familiar and pleasant frog's song is actually like the wonderful music that nature can never finish playing, a quiet and harmonious song of the field. "In the fragrance of the rice flower, say good year, listen to the sound of frogs", there are frogs calling farmers have the hope of sowing, there are frogs will have the joy of harvesting and joy!
Once upon a time, there was a wide expanse of ponds in the suburbs and villages, where frogs lived and breathed. However, almost overnight was swallowed by the spread of the city, some of the remaining frogs into a real frog at the bottom of the well, although they are fortunate enough to survive, but unfortunately lost the field, lost the seedlings, lost the activities of the world and freedom, and even only until the depths of the night time, only dared to be born to send out a few chirps, gently, slowly, as if afraid of disturbing the city of the magnificent dream, but also seems to call out to their companions far away from the sound of a voice. Called away from their companions. But they are more and more companions are also more desperate wailing in other corners of the city! A pair of greedy hands to catch them from the field, and a pair of numb hands to buy them, they have not had time to look at the strange city, they were born into a family case on the chopping block of meat! Compared to a pair of greedy or numb hands, their resistance seems so weak and feeble, they only issued a miserable and desperate wail!
Most species of amphibians have declined on Earth, and the living species are rapidly becoming endangered species of the blame is attributed to a number of aspects, the most important of which is the frequent human activities and the rapid development of global industry, on the one hand, it led to the extinction of the species; on the other hand, due to industrial pollution, especially the chemical industry, so that ecological degradation of the environment is increasingly worse, so that the wetland Large-scale destruction of wetlands.
Recent studies have found that triphenyltin, a compound used as an agricultural fungus inhibitor, may cause several species of frogs to develop malformations or even die even at levels below field concentrations.
The fungicide, triphenyltin, is used mainly against diseases in sugar beet and potatoes, but is sometimes used in a wide range of crops such as onions and rice. This inevitably contaminates aquatic ecosystems, some directly in rice paddies, and others in rivers and ditches through surface runoff. Because of the slow liquid-phase degradation of triphenyltin, it leads to its enrichment in water, thus causing great toxicity to aquatic organisms, especially damaging the central nervous system of the tadpole brain.
In general, the higher the concentration of a fungal inhibitor, the more toxic it is to the organism. In the case of amphibians, chemicals often cause developmental stunting, which in turn will make it difficult to escape predators. This is likely to have contributed to the extinction of frog populations in some areas.
There are other pollutants responsible for the decline of amphibian populations in many more areas, and acid rain is one of the main culprits. In fact, almost all amphibian eggs and larvae can't survive in water with a pH below 4.5. Yet acid rain, which generally has a pH of 3.5 can reduce the normal pH of water in ponds and streams to lethal levels. Acid rain has been identified as a cause of amphibian decline in ponds and lakes in Canada, Scandinavian countries and Eastern Europe.
Perhaps unaccountable for the decline in amphibian populations in larger regions, or even globally, is the decline in ozone. A thinning of the Earth's ozone layer and a rise in ultraviolet radiation will prevent amphibian eggs from hatching into young. The other amphibians most likely to be affected by increased ultraviolet radiation are those that live more alpine and closer to the poles, areas where the ozone layer is thinnest and where amphibians must bask in the sun to regulate their body temperatures, with the result that exposure to radiation increases and deoxyribonucleic acid molecules are destroyed.
Environmental hormones may also be responsible for the global decline in amphibian populations, as pollutants from the breakdown of pesticides such as DDT have the potential to severely damage amphibian reproduction, similar to what happens to aquatic organisms such as fish and crocodiles. In fact, it has been found that the environmental hormone that masculinizes some female tree frogs also feminizes male tree frogs of other species, and as a result, none of these tree frogs can reproduce. This hormone molecule, which does not break down easily in the environment, is deposited in the sludge at the bottom of ponds and lakes, where it is swallowed by the larvae of bottom-dwelling amphibians. The hormone, a very small buildup can take effect, and is extremely easy to disperse on the wind, making it a global threat regardless of its native habitat.
The Earth's growing greenhouse effect is not only causing strange changes in the climate, but also a gradual increase in the number of color-changing frogs, which are appearing in many places in a variety of oranges, whites, and even pinks, a phenomenon that surely isn't nature playing a joke on humans.
The deformed frogs found in multiple locations in North America are the result of living in environments with excessive levels of the vitamin A complex, which contains retinoic acid, a hormone that controls several important aspects of vertebrate developmental processes, and an excess of which can also lead to reproductive deformities in humans.
In the United States, wetlands near lakes and rivers have been home to some severely deformed frogs, some with only three legs, some missing the first two legs, and some with three or four long hind legs. This news has caused shock and close attention from environmental experts and people around the world. In this regard, some people believe that parasites play tricks, some believe that the culprit is pesticides, while others believe that the destruction of the ozone layer caused by excessive ultraviolet light pollution of the environment and lead to animal deformities. The most likely cause is contaminated water. What can be confirmed is that the water source is contaminated by a variety of substances, including special insecticides, heavy metals, chlorides, and of course, other chemical contamination can not be ruled out.
Because frogs are amphibious, they are generally considered to be accurate barometers or indicators of environmental health. Frogs are more susceptible to teratogens and therefore more vulnerable as their embryos are directly immersed in water during development. In the case of humans, although their embryos are protected by a number of factors during development, the pathway through which hormones cause frogs to become malformed can also affect humans, and the possibility of human malformations also exists. There is no doubt that what can deform a frog can also deform a human being. It is only a matter of time before that day comes.
Thus, we conclude that to protect the ecological environment is to protect human beings themselves!
Frogs are amphibians without tails such as frogs (black-spotted frogs) and toads (commonly known as toads), which are classified as belonging to the phylum Chordata, the subphylum Vertebrata, and the class Amphibia. Because of the bare skin, can not effectively prevent the evaporation of water in the body, so they can not live their lives away from water or humid environment, afraid of drought and cold. So most of them live in tropical and temperate rainy areas, and there are very few species distributed in the cold zone. There are about 130 species of frogs in China, and almost all of them are capable of eliminating forest and farmland pests.
The frogs commonly found in farmland include the black-spotted frog, the zephyr frog, the golden-line frog, the flower-backed toad, and so on. The bullfrog introduced from Cuba can be regarded as a "giant" among frogs, with a body length of up to 20 centimeters. Its mooing sound is very similar to that of a cow, so it is called a bullfrog. In fact, China also has a very large body frogs, such as living in the paddy fields of Jiangnan tiger frogs, more than 12 centimeters long, the sound is like a dog barking. Spiny frogs living in the mountain streams of Jiangnan, also known as "stone chicken", also has a body length of about 12 centimeters. So how big is the smallest frog in China? Only slightly larger than a broad bean. Early spring in February, when the north is still snow and wind, Hainan Island has been flowers blooming. At this time, during the day near the rice paddies can be heard "croaking" sound. This is one of the smallest frogs - Ji frog in courtship. It is only 2.5 centimeters long, and when it chirps, a large air bubble - the song sac - bulges out of the lower part of its throat. Sometimes, you can hear a squeaking sound coming from between the water plants, which is the song of a small, hard-to-find frog, the floating frog. Floating frogs are gray, only 2 centimeters long, often floating in the water between the grass, only showing a head. Whenever there is a movement, they immediately dive and escape. Don't look at these frogs small body, they are small pests and termites natural enemy. Tree frogs in our country about a dozen species, they are light and thin, finger end of the sucker, good climbing tall tree trunks or short bushes, body color and the surroundings of the same.
Reproduction in frogs is characterized by dioecy, fertilization in water, and oviparity. Reproduction occurs around mid to late April each year. During reproduction, frogs have a very special phenomenon - holding pairs. It should be noted that the frogs are not mating, but only a part of the reproductive process, studies have shown that if the male and female frogs are artificially separated (i.e., there is no process of holding pairs), the female frogs can not excrete egg cells even in the reproductive period of the frogs. The biological significance of holding pairs is that the female frogs can be induced to ovulate by holding pairs. Generally, frogs lay their eggs and fertilize them in water, and the eggs hatch into tadpoles, which live in the water and then become young frogs that land and move around. However, tree frogs lay their eggs in a different way. Spotted-legged tree frogs produce eggs that look like white soap suds and cream, which stick to the water plants. The most interesting is the Emei Tree Frog, which lays its eggs on leaves at the water's edge, where the eggs develop, then fall into the lake and continue to develop. Another example is the pleasantly chirping lyre-bouncing frog, which also builds a mud nest before laying its eggs, and then lays its eggs in it. Some frogs that are tree frogs do not go up into the trees, but live in the water. Some tree frogs, such as the red-webbed tree frog and the black-webbed tree frog, have broad webbing between their fingers and toes, and are able to glide from high branches to low places with their webbing, so they are also called flying frogs. Besides tree frogs, there are also rain frogs and turbulent frogs that have suckers. Among them, the turbulent frogs are more special, they like to live in the turbulent waters, and they can cross the rapids and climb up the rocks with agility. The tadpoles of the turbulent frogs are also peculiar in that they have a suction cup on their abdomen, which can be attached to rocks to prevent them from being washed away by the rapids. The toad with a "beard" is a rare frog endemic to China, first found in Emei Mountain, and later found in several southern provinces. This kind of frog has a wide, rounded, flat muzzle, and 12-16 vertebral horny black spines on the edge of the male upper jaw, so it is called the bearded toad. The function of these "beards" is still under study. There are many species of frogs, but all of them feed mainly on pests.
What frogs do
1.Catching insects
There is a pond in front of my house, surrounded by crops and weeds. Every summer, frogs make their home by the pond and become my neighbors. I often went to the pond to watch the frogs, and slowly became familiar with their characteristics and habits.
The frogs love to eat small insects, and the way they catch them is really interesting. One day after dinner, I squatted by the pond to watch the frogs catch mosquitoes. A frog lying in a small mound, back legs curled up on his knees, front legs to support, open mouth tilted face, stomach bulging and waiting for something. Suddenly a mosquito flew over and waved in front of the frog, only to see the frog's body leap upward, flip its tongue, and fall to the ground again. The mosquito disappeared, and it sat down again as it was, waiting. I heard Uncle Farmer say that a frog can eliminate 10,000 pests a year, it is really our good friend!
2. Singers
The frog has a bulge around its mouth that makes sounds. When is its favorite time to let out a song?
On hot summer days, frogs usually hide in the grass and occasionally shout a few times for a short time. If one of them calls, the one next to it will also call out a few times, as if they are singing along. The time when the frogs call most joyfully is after a heavy rain. Whenever this happens, there will be dozens or even hundreds of frogs "croaking - croaking" endless, the sound can be heard for miles, like a magnificent symphony, as if singing for the agricultural harvest!
The frog's vocal organs are vocal cords. Located above the cartilage of the laryngeal valve. Some male frogs on both sides of the corner of the mouth and can be drummed up vibration of the external acoustic capsule, the acoustic capsule produces *** sound, so that the frog's song majestic, bright after the rain, when you walk to the pond, you will hear the male frogs barking with each other, one after another, converging into a chorus. Scientific workers pointed out that the chorus of frogs are not each singing, but there are certain rules, there is a leader, chorus, sing, sing and other forms of accompaniment, each other closely match, is a veritable chorus. It is speculated that the chorus is much superior to solo singing, because it contains more information; chorus sound is loud, spread far, can attract more female frogs to come, so the frogs often use the chorus form.
3. Sportsman
Look, a frog is in the grass, waddling and crawling.
With its bulging eyes and triangular head, and with such a sluggish crawling motion, you might think it's a bit silly. However, when you get a little closer, it jumped, jumped into the pond with floating weeds. It's a jump that's 20 times as long as it is!
Then it swims to the other side of the river in the standard breaststroke position.
The frog is a good jumper and an expert swimmer!
4, camouflage master
Besides the white belly, the frog's head and back are yellowish-green, with some black-brown spots on them. Some have three white marks on their backs. Why are frogs green?
It turns out that the frog's green clothing is a good camouflage, it is almost the same color as the grass in the grass, and it can protect itself from enemies.
PS: In internet language, it specifically refers to ugly-looking boys!
It is said that there was a man who was so ugly that his family tried to arrange a marriage for him, but as soon as the matchmaker saw him, he threw up with a wow and ran away quickly. This is a lot of times, he is also accustomed to, but the parents are not willing, every time the matchmaker came, he carried a spittoon over, said: please wow. I knew you were going to throw up, but please do it in the spittoon so as not to dirty the floor. Later, the word spread, and the neighbors knew about it, and the word "please" gradually spread. Later, it evolved into seeing someone ugly, said: please wow, meaning that the story of this young man, you are very ugly and bad, let people want to vomit. Over time, the word slowly evolved into a frog, there is this phrase, convenient.