The respiratory organs of reptiles are lungs, and some breathe through the skin. Their skin is covered with scales. They belong to temperature-changing animals and can't control the temperature in their bodies, so they can't find reptiles in cold areas and hibernate in winter.
Reptiles fall into three categories: turtles, crocodiles, snakes and lizards.
1, turtle
There are about 330 kinds of reptiles. Their bodies are short and wide, and their soft bodies are hidden in thick and hard shells. They have no teeth, but their jawbones are very hard and can cut off food.
Tortoise's sense of smell and touch is quite developed, but its hearing and vision are not keen. Most turtles are gentle and not aggressive. When they are hurt by the enemy, they all shrink back and hide in turtle shells. Looking at a shell as hard as a stone, the enemy is often at a loss. It is with this special skill that turtles have lived on the earth for 200 million years and will continue to live happily. The life span of turtles is very long, generally around 70 years old, and most turtles can live to 100 years old.
Turtles breed by laying eggs, which are very secretive. During the annual breeding season, female turtles quietly climb to the beach under the cover of night, and choose a sunny and moderate temperature place as the spawning ground. Before laying eggs, turtles urinate on the sand to make the soil moist and soft, and then dig a hole with their hind feet. When the hole is dug to a depth above 10 cm, the tortoise begins to lay eggs in the hole. The turtle egg is about the size of a ping-pong ball, with a hard calcium shell outside. This shell is the protective layer of the egg, but it is an obstacle for the young turtle that is about to rise. Fortunately, there is a hard protrusion between the baby turtle's mouth and nose. With this "shell breaker", the young turtle struggled to drill, grind and struggle, finally drilled a small hole, tried his best to break the eggshell with his head, and the young turtle began to breathe for the first time. With the rise of the young turtle, the night of its survival crisis came. Young turtles are a delicacy for seabirds, lizards, dogs and snakes. Young turtles are often eaten on the way to the seaside or river ponds. Of the 65,438+000 baby turtles, only a few can survive.
Turtles are the biggest turtles. The length of their nails is generally around 100 cm. In addition to laying eggs or basking in the sun, turtles have been living in the sea, and their feet have become fins, so that turtles can swim freely in the water.
Turtles have three eating habits. Turtles are mostly herbivores, feeding on straw and plant leaves. Turtles are mostly carnivores. They prey on mollusks, shrimps and crabs. Freshwater turtles are mostly omnivorous turtles. They eat vegetarian food such as aquatic plants, as well as river shrimp, frogs and fish.
There are about 32 known species of soft-shelled turtle. They live in fresh water. Turtles often dive into the sediment at the bottom of the water, so their shells become flat and flat. The web between the toes of the tortoise is very developed, and it moves quickly in the water and swims very fast. Turtles are natural divers. Its neck and nose are very long, which enables it to lie on the bottom of the water and breathe through its nose.
2.crocodiles
Crocodile is the largest and most dangerous reptile in existence, and it is also the most advanced reptile. There are 22 kinds of crocodiles, which live in tropical areas all over the world. The largest crocodile is the Indo-Pacific crocodile, also known as the saltwater crocodile, which is 7 meters long and weighs about 300 kilograms. They can still be seen in the offshore 1000 km ocean. Although their habitats, sizes and habits are different, they all have a ferocious appearance. The crocodile's body is very long and covered with scales, and its teeth in its mouth are like a row of small daggers; The tail plays the role of rowing and controlling the direction of the rudder.
Crocodiles are carnivores, feeding on insects, frogs, snails, fish, turtles, birds and large mammals. Crocodiles are very cunning when hunting. They always hide their bodies in the water, leaving only their eyes, ears and nose out of the water. From a distance, they look like a dead wood floating on the water. When the prey on the shore is found, this "dead wood" will move to the shore unnoticed, and then pounce on the prey with lightning speed, bite it and drag it into the water. After several struggles, the prey became food for crocodiles.
Crocodiles will have hundreds of teeth in their lifetime-but they will not grow at the same time. Crocodiles often break or lose their teeth when hunting, so they will grow new teeth as substitutes. "crocodile tears" is synonymous with hypocrisy. In fact, crocodile tears have nothing to do with crocodile's mood, but the way it excretes excess salt in the body. Crocodiles don't sweat and their kidneys have degenerated. They have special excretory glands in their bodies to expel salt, and their excretory ducts are just around their eyes. Crocodile tears are actually a salt solution.
3.lizards
Speaking of lizards, many people find it strange that they can only be seen in tropical jungles. If someone tells you that lizards live in almost every family in the world, you will be very surprised. Indeed, the gecko is a lizard. Many people keep geckos, and geckos help people eliminate pests in their rooms. Lizards are a thriving reptile group with 3000 species.
Lizards are mostly carnivorous, feeding on mollusks such as insects and snails; Others are omnivorous. Besides fruits and flowers, they sometimes eat snails. Some large and docile lizards are pure vegetarians.
Lizards have many natural enemies. Spiders, scorpions, snakes, birds and mammals all prey on lizards. North American and Mexican poisonous lizards defend themselves with venom, while other lizards mainly rely on special defense or escape skills when attacked by natural enemies. Most lizards have good camouflage. When they are in danger, they just need to sit quietly and wait for the predator to leave. A chameleon can change its body color to match the background color and stay still when a predator approaches. There are also some lizards that will surprise or scare predators and win the chance to escape. Australian umbrella lizards will suddenly open their gills, some lizards will hiss with their throats stretched out, some will hold their breath to make themselves bigger than predators or too big to swallow, and some will even stick out their colorful tongues! Many lizards have special escape methods. If they are caught by predators, they will leave twisted tails to distract the predators so as to escape by themselves. Some lizards have sharp spines, which will stab the mouth of predators; Others have smooth scales, which makes it difficult for predators to catch them. Of course, it is also a good way to survive to escape quickly so that the enemy can't catch up.
Horned lizards are the strangest lizards in defense. Its weapon to scare away predators is actually its own blood. It uses special muscles to burst the capillaries inside and around the eyes and spray blood 65,438+0 meters away to scare away predators.
The chameleon is a very famous lizard, and its body color can change with the change of light and temperature. Where the light is strong and the temperature is high, the chameleon will turn green, and where the light is dark and the temperature is low, the chameleon will be brown. The chameleon will even show different body colors due to different moods. Another very interesting feature of the chameleon is that its two eyes can turn separately and look at each other, which enables it to find its prey quickly.
Gecko's toe is a very important climbing organ. Gecko toes have deep grooves, just like "suction cups". When the gecko presses flat on the glass, the air between the toes and the glass is exhausted and adsorbed on the glass. Gecko's toes also have slender cilia, and each cilia has hundreds of small protrusions. These cilia and protrusions can increase the friction between the toes and the glass, so that the gecko can walk freely on the glass.
4. snakes
Snakes, especially poisonous snakes, are reptiles that frighten everyone. They have no limbs, but they climb very fast. The slender body is covered with scales, the snake head is angular, and the eyes on the head are shining with terrible light. A snake's mouth can be opened wide, and food bigger than its own head can be swallowed in one gulp.
Snakes are carnivores, feeding on birds, lizards, mice and mammals. Some snakes also kill their own kind, while sea snakes feed on fish.
The snake's ears have degenerated, and its hearing and eyesight are poor. It can only see things nearby. So how does the snake know if there is any prey nearby? Snakes can feel the slightest vibration from the ground or air through their skin. They use their whole skin instead of their ears.
Snakes have a very developed sense of smell. Unlike other animals, the snake's olfactory receptor is the tongue, not the nose. Snakes often stick out their tongues and keep shaking. The snake's tongue has two forks, which can absorb tiny odor particles in the air and distinguish different odors.
The snake's eyes have degenerated, and voles can be caught at night, relying on the buccal fossa between the eyes and nostrils. Buccal fossa is like a snake's infrared receiver, which can judge the position of prey according to the received temperature. Scientists invented an infrared automatic tracking device according to the function of snake buccal fossa. After the projectile carrying this device is launched, it can automatically track the target and destroy it.
The teeth of a poisonous snake are connected with the poisonous glands in the head. When a poisonous snake preys, the venom flows out along the fangs, paralyzing the prey. There are two kinds of tusks, one is teeth with grooves, and the grooves lead to venom; The other is a tube tooth, the tooth body is slender as a needle, and there is a tube in the middle, which is hollow and communicates with the poisonous gland. Venom is also divided into two types, which affect prey in different ways. One is nerve poisoning and the other is blood poisoning.
Not all snakes live only on land, some live in water. They are called stray snakes. Most snakes that swim are nontoxic, but sea snakes that live in the ocean are toxic. Their lungs are so big that they can absorb a lot of air at a time and store it. Sea snakes living in lakes and swamps can chase fish all the way to the estuary.
Interviewee: 3000 wjh- Trainee Magician 3-29 19:25
A long time ago, about 200 million to 70 million years ago today, there lived a huge family on our earth. They rule the sea, land and sky, and all other animals can't compete with them. They are the real overlords, and this is the dinosaur.
At that time, the earth's climate was warm and humid, and there were dense forests everywhere. There are all kinds of animals living in the forest, so whether dinosaurs ate plants or animals, they enjoyed endless food. Because of such a good environment, dinosaurs generally grew huge. It is speculated that the largest dinosaur is 30 meters long and weighs 40 to 50 tons, and now the largest bus can't pull it. Of course, there are smaller dinosaurs, such as Palatosaurus, which is only 60 cm long and weighs 3 kg, which is similar to the chicken we see.
However, such a huge family suddenly and quickly disappeared from the earth. It disappeared at the end of what scientists call the Cretaceous period. Why dinosaurs suddenly disappeared so cleanly is a scientific mystery. People have been speculating for many years, but there is never a clear answer. Fortunately, some dead dinosaurs did not disappear completely. Their bones became fossils and were preserved by nature, which made us know that there were such animals in the past and described their appearance according to these bones. If you are interested in dinosaurs, give it a try and see if you can solve this eternal mystery.
The study of dinosaurs is very meaningful. It can not only help us understand the evolution of life on the earth, but also help us understand the changes of the earth's climate, the state of geological activities, the relationship between ourselves and the environment, and even all aspects of the universe.
There are many kinds of dinosaurs. According to the shape of their skeletal fossils, scientists divide them into two categories, one is called bird dragon and the other is called sauropod. According to their tooth fossils, we can also infer whether they are carnivores or herbivores. This is just a rough classification. According to the restoration of dinosaur skeleton fossils, we found that dinosaurs were not only diverse, but also amazing in shape. Some of these dinosaurs flew in the sky, some swam in the water and some crawled on land. Let's get to know them.
Chiroptera lived in Cretaceous, and their bones were found in Europe. Pterosaur is not very big, its wings are only about 22 cm. But the wings of Fengshen Pterosaur were as long as 12 meters, as big as a bus. American scientists once found a pterosaur whose wings were more than 15 meters long. If we can see it today, we may think it is a plane flying in the sky. Many flying birds and dragons are a bit like bats today. They seem to hold up huge wings with one hand, so having wings and claws has become a major feature of them. Some people think that later birds evolved from them.
How did the giant pterosaur fly into the sky? Scientists have different understandings of this. Some people think that those giant pterosaurs can't fly at all. They can't flap their wings like birds, but they can climb high first, spread their huge wings against the wind and glide in the air with the help of updraft. Some people think that the membrane on pterodactyl wings is very hard, and the outer side of wings is connected by bones and muscles like a frame, which can flap wings like a bird. Because their wings are very big, they can get a huge reaction force by flapping gently and let them fly. Which of these two views is correct is still inconclusive. Maybe you can crack it in the near future.
When dinosaurs ruled the land, the ocean was also occupied by some huge reptiles. They are close relatives of land dinosaurs and pterosaurs in the air. They also breathe air with their lungs and usually lay eggs. They are the overlord in the ocean, and some have sharp teeth in order to prey on other fish. These reptiles look more or less like fish today. Some people think that it was changed by fish, while others think that today's fish were changed by them. There are many kinds of these sea trolls, such as eels, turtles, snakes, crocodiles, etc., which used to be similar. Such as eel dragon, such as plesiosaur and so on. The platysaurus is the longest plesiosaur, with a total length of 15 meters. Its neck is about twice as big as its trunk.
Eel dragon is a kind of plesiosaur. Their fossils were found in Japan. After measurement, their body length is about 7 or 8 meters. They have sharp teeth.
Scientists accidentally discovered a small dinosaur fossil while digging protoceratops's nest. What did it do in protoceratops's nest? After research, it turned out to be a small villain who specialized in stealing dinosaur eggs. It has no teeth in its mouth, only a sharp thorn, which is the tool it uses to pierce and suck egg juice.
Dinosaurs on land are the most familiar to us, perhaps because their skeletal fossils are easier to preserve. There are many such dinosaurs found now, including theropod dinosaurs, such as Alloodon; Stegosaurus, such as stegosaurus; Ankylosaurus, such as forest dragon; Ceratosaurus, such as triceratops; Lei Long, such as Lei Long and so on.
Allosaurus is a fierce and terrible carnivorous dinosaur, and its big mouth can swallow a pig at once. Its teeth are all bent inward, and its prey can't escape when bitten.
When protoceratops lays eggs, several females often share a nest, and everyone forms a circle to lay eggs in turn. It seems that they are United.
Triceratops is a kind of ceratosaurus. It has a horn on its nose, like a rhinoceros, and two horns on its eyes, like an ox. These three horns are all 1 meter long and are powerful weapons for their fighting.
There is an eye-catching tube on the head of the cockscomb dragon, and there is a thin passage in it. When the air passes by, it will make a low sound, which can be used to scare away the enemy. Some people think that it is used for ventilation when diving, but what it is used for is still inconclusive.
This is a kind of Ankylosaurus. Their skin is very hard, like armor. There are bone spurs on the body and tail, like maces, and no one dares to touch them.
Lei Long is the largest dinosaur, some of which are more than 30 meters long and as high as six floors. They are all animals that eat grass or leaves. Most dinosaur fossils we see in museums are of this type.
About 200 million years ago, geological history began to enter the Mesozoic era, and dinosaurs appeared on the earth. In the next 65438+ billion years, the dinosaur family became more and more huge. Later, it seems that they suddenly disappeared one day, leaving us with countless mysteries. Through the unremitting exploration of scientists, we gradually got to know something about dinosaurs. It turns out that although dinosaurs were big, stupid and terrible, their stories were actually quite interesting.
The story of the mother dragon: People used to think that dinosaurs, like reptiles today, laid eggs all their lives and left, no matter what would happen to their children. Later, scientists found that the teeth of some young dinosaur fossils had obvious wear marks, which indicated that they had begun to eat. However, the limbs of these young dragons are not fully developed, and obviously they have not started to crawl in the real sense. It seems that the young dragon was raised by his parents in the nest. In addition, the analysis of dinosaur footprint fossils shows that they often go out in procession, with big dinosaurs on both sides and small dinosaurs in the middle of the queue, just like the elephants we see today. So scientists gave this dinosaur a very humanized name, the female dragon. However, there are also many people who believe that these evidences alone cannot prove that dinosaurs raised their offspring purposefully. Because no reptile in the world shows such love now. What crocodiles do best is to take the baby crocodile out of its shell in its mouth and bring it to the water's edge, even if the task is completed. As for whether the crocodile can swim or hunt, it doesn't matter. Cimulong can lay 25 eggs at a time. These 25 little dinosaurs eat hundreds of pounds of fresh plants every day. Cimulong needs to find his own way to find food. If so, they are worthy of the title of mother dragon.
When people first discovered stegosaurus, they noticed that it had many bone plates on its back. At first, scientists estimated that these bone plates were laid flat on dinosaurs like protective covers. Later, after careful investigation, it was finally determined that the bone plate was upright. The surface of these bone plates is covered with cracks and many grooves. These cracks and grooves are full of blood. When the temperature drops, stegosaurus will open the bone plate to absorb the heat of the sun. When the temperature rises, it will turn the bone plate and use the cool wind to dissipate heat. Stegosaurus had a very small head and a brain the size of a walnut, which was out of proportion to its huge body. Scientists therefore decided that Stegosaurus must be very stupid.
Among the dinosaur families, the largest belongs to Liang Long. They are tall and long, just like a building. Supposedly, Liang Long, with such a huge body, should be very light in weight, but in fact they only weigh 10 tons, and those dinosaurs who are much smaller than them are often several times heavier than them. It turns out that Liang Long's bones are very special. They are not only hollow inside, but also very light. Therefore, a behemoth like Liang Long will not be overwhelmed by his huge body.
Along the Ryder River in Canada, there used to be many dinosaurs, one of which was called Albertosaurus. This dinosaur belongs to the same family as Tyrannosaurus Rex. Compared with ordinary dinosaurs, their bodies are smaller, but they are more terrible to other animals. Because they run very fast, it is estimated that they can reach a speed of more than 30 kilometers per hour in a short distance. The terrible thing about Albertosaurus is that its mouth is very big and full of sharp teeth, which can break hard bones, not to mention the thick skin of other dinosaurs. In addition, their front paws are as sharp as eagles, and it is difficult for any animal to escape bad luck if it is caught by them.
1993, scientists found a large number of dinosaur eggs in Xixia county, western Henan province. Before this, humans have found more than 500 dinosaur eggs, and this time there are more than 5,000 dinosaur eggs unearthed in Xixia, and it is estimated that tens of thousands of them have not been unearthed. For a time, the world was shocked. But why do so many dinosaurs go to Xixia to lay eggs? Scientists speculate that dinosaurs like to lay eggs near the water, facing the sun, in higher places. Xixia just meets these conditions. Xixia in paleogeological age is a basin with many lakes and swamps, and its climate is warm and humid, which is suitable for dinosaurs to survive.
In the past, all scientists thought that dinosaurs were cold-blooded or warm-blooded like all reptiles, but with the increasing number of fossil data, people's understanding has also changed. Some people think that some dinosaurs may be warm-blooded animals. First of all, they think that some dinosaurs are extremely agile, and they don't crawl on the ground like snakes, but run on the ground with two hind legs, which can reach 20 to 90 kilometers per hour. This requires a strong heart and a high metabolism, which is obviously impossible for cold-blooded animals. Secondly, dinosaurs ate a lot. It is speculated that a 30-ton sauropod dinosaur may eat nearly 2 tons of food every day, and only warm-blooded animals need so much energy. This is also reasonable from the point of view that carnivorous dinosaurs are far less than herbivorous dinosaurs. In addition, there are some smaller dinosaurs, who are likely to be covered with a layer of feathers or hair, which is also to prevent the loss of body temperature. Other aspects, such as the study of bones, also preliminarily show that some dinosaurs were warm-blooded animals. As soon as the theory of warm-blooded dinosaurs was put forward, it was strongly criticized, but it is still difficult to reach a conclusion.
On our earth, there used to be many biological species that appeared and then disappeared, which is an inevitable stage in the history of biological evolution. But why a huge and dominant family like dinosaurs suddenly disappeared from the earth can't help but arouse our speculation. At the end of the Cretaceous period 65 million years ago, scientists have been arguing about what caused the death of dinosaurs and a large number of other creatures. Some people say that there was a geological orogeny on the earth at that time, because there were many mountains on the flat land, so the swamp was reduced and the climate became less humid and warm. The dinosaur's respiratory organs could not adapt to the dry, cold and dry air. In winter, the dinosaur ran out of food, so it came to a dead end. Some people say that the supernova explosion caused a strong change in the earth's climate, the temperature suddenly rose, and then dropped very low. Others say that dinosaurs ate a lot of flowering plants, and there were many toxins in these flowers. Dinosaurs ate a lot, so they died of poisoning. The evidence is that flowering plants began to appear at that time. Others ingeniously said that it was because dinosaurs, a huge animal, ate too much and kept farting, releasing a lot of methane gas into the air. Because they are too numerous and have a long life span, they have destroyed the ozone layer of the earth and caused a devastating climate. Some people even say that it is the result of aliens coming to the earth to hunt, because they think dinosaur meat is particularly delicious. The evidence is that the dinosaur bones they found in the North Pole were marked by laser cutting. In short, it is really varied and strange. But the meteorite impact theory is generally recognized.
1980, American scientists found a high concentration of iridium in the stratum 65 million years ago, and its content exceeded the normal content by dozens or even hundreds of times. This concentration of iridium can be found in meteorites, so scientists associate it with the extinction of dinosaurs. According to the content of iridium, it is also inferred that the impact object is an asteroid with a diameter of 10 km. The impact of such a large meteorite on the earth is absolutely unparalleled. According to the earthquake intensity, it is about Richter scale 10, and the diameter of the crater produced by the impact will exceed 100 km. It took scientists 10 years to finally get the preliminary results. They found this crater in the stratum of Yucatan Peninsula in Central America. It is estimated that the diameter of this pit is between 180 km and 300 km. Now, scientists are still doing further research on this pit.
Scientists began to paint us a heroic picture 65 million years ago. One day, dinosaurs were still eating and drinking carefree in paradise on earth. Suddenly, a dazzling white light appeared in the sky, and a boulder with a diameter of 10 km equivalent to the size of a medium-sized city fell from the sky. It was an asteroid, which fell into the sea at a speed of 40 kilometers per second and fell into a huge pit on the bottom of the sea. Seawater is rapidly gasified, and steam is sprayed into the sky for tens of thousands of meters. Then the tsunami was as high as 5 kilometers, spreading at an extremely fast speed, and the turbulent sea water swept everything in the landing area. After the turbulent waves swept the earth's surface, they met at the back end of the impact point. The huge seawater power triggered a strong volcanic eruption on the Deccan Plateau here, and the movement direction of the earth plates occurred simultaneously.
What a terrible disaster this is. Meteorites hit the earth and produced a lot of dust, polar snow melted, plants were destroyed and volcanic ash filled the sky. For a time, the sky was dark, the temperature plummeted, and the dinosaurs were swept away and buried by heavy rains, flash floods and mudslides. In the next few months or even years, the sky is still dusty and covered with dark clouds, and the earth enters a low temperature because it has not seen sunlight all the year round, and the vast land is silent for a while. Thus an era in the history of biology ended.
Whether the above-mentioned things really happen or not, the total extinction of dinosaurs will be a strange thing. Fortunately, we have now acquired some precious dinosaur fossils, which enables scientists to carry out their research work. We hope that this mystery will be solved in the near future. At the same time, we should know that any living thing has to go through the process of production, prosperity and extinction. This is a natural law and will not change because that species is huge and powerful. Dinosaurs went extinct, and then a whole new era appeared. More and more advanced biological worlds have better decorated the earth.