100000 whys have played a positive role in disseminating knowledge and popularizing science, which has influenced generations of teenagers to embark on the road of science, closely follow the pulse of the development of the times, and have an insight into the changes in readers' needs for science education. Here are 100000 whys animal knowledge I carefully recommend for reference only. Welcome to read!
Why is coral an animal
Coral is actually a lower animal. It belongs to coelenterates with only two inner germ layers. It looks like a double-layer pocket, but there is no anus. The food goes in and the undigested residue is discharged. There are many tentacles around the mouth. Tentacles can catch food or vibrate to cause water to enter the mouth and intestines to help digest small organisms in the water.
Because most corals can germinate and reproduce, and these buds do not leave the mother, they will eventually become an interconnected and common group, which is the main origin of corals as branches. We call each monomer of Shanhu "coral insect". The coral we usually see is the skeleton of the group left after the body of these coral insects rots. Some bones have rough texture and can be used as raw materials for burning lime and making artificial stone; Good texture can be used as building materials. Most of the common coral reefs in the sea are formed by the accumulation of these bones.
Coral reefs are reefs distributed around some coasts, islands and reefs in the tropical ocean, which are formed by the long-term accumulation of coral exoskeletons, rocky algae and shells. The formation of coral atolls is formed under the long-term combination of biological action and crustal movement.
Darwin once carried out quite in-depth and successful research on corals. He not only pointed out the general law of coral reef development, but also scientifically explained it with the theory of "site subsidence". Darwin first divided corals into three types: shore reef, barrier reef and Atoll, and clearly pointed out that: from shore reef to Barrier Reef, and then from Barrier Reef to atoll is a continuous process, that is, "when the base of the island of train rock stratum gradually sinks at regular intervals, reef building corals continue to build coral islands upward." "We must think of a coral island as a monument raised by hundreds of millions of small architects, which shows that there is a former land lying under the sea and buried in the depths of the ocean."
American Canadian scholar Daley put forward the "glacier Cybernetics" to explain the development of coral reefs. He believes that in the last glacial period, when the island was flattened and the sea water slowly melted, coral reefs began to form on the edge of volcanic islands that were not completely flattened. Due to the more suitable edge environment and rapid growth rate, atolls were gradually formed.
A large number of volcanic remains have been found deep under the coral reef of Midway Island, which supports Darwin's theory, but the change of sea level also seems to play a very important role in the formation of coral islands.
Hard coral reefs are the protective gods of the coast. They can block the rough waves and protect the land, beaches and fertile fields behind them from invasion. They are also known as the great wall of the sea. Like mangroves, it can slow down the impact and damage of tsunamis and floods. It is a natural protective embankment. Coral reef is an ecosystem with the most species in the ocean and an important fishery resource. It is of great significance to the protection of global biodiversity.
Why do animals have tails
Many animals drag a tail behind their bodies. They are long or short, large or small, smooth or covered with fur. They are very cute. For example: Goldfish in the water kept wagging its big tail, like butterflies dancing in the air; In spring, the male peacock unfolds its gorgeous tail feathers and sets up a gorgeous "fan screen" behind him. The bright copper and brilliant blue eye spots are shaking like dozens of pairs of bright eyes; When squirrels jump in the tree, their big, bulky tail is also very beautiful... So why do they have long tails?
Let's see what animals' tails are doing first. Carefully observe the goldfish, you may find that it can move forward or turn with the swing of its tail. Yes, fish swimming in the water can use their tails to gain the power to move forward. If they need to turn or turn around, it's easy to change direction. They can do it by swinging their tails. Although penguins, dolphins and whales are not fish, their tails also have similar functions. What's special is that some fish's tails have other functions. For example, some sharks can use their long and powerful tails to drive away fish, even knock them out and have a good meal.
Animals living on land can also use their tails to complete various tasks. The crocodile's tail is thick and thick. It is a good weapon to attack the enemy or prey. Geckos and lizards have flexible tails, which can be disconnected in time to escape when caught. Male peacocks show off their beautiful "fan screen" and win the favor of female peacocks. Sparrows, turtledoves and other birds rely on the feathers on their tails to steer and control flight and landing. Squirrels and cats jump flexibly on trees without falling down, thanks to the balance controlled by their tails. Good at jumping, jerboas and kangaroos benefit from their long tail, which can be used as a pillar when they stop. The tail also acts like a "hand". For example, capuchin monkeys and nestling rats can wrap their long tails around branches and hang upside down; Cattle and zebras can swing their tails around to drive away annoying mosquitoes and flies. The tail can also express feelings, and the dog will "wag its tail and beg for mercy"... The function of the tail has been played incisively and vividly by animals.
From the perspective of internal anatomical structure, the fundamental reason why animals have tails is that there is a "pillar" - spine, which runs through the body and is similar to the "domino" strung together. Multiple or dozens of "dominoes" at the end of the pillar are the tail vertebrae to which the tail is "attached". With the different degrees of healing or degeneration, various tails that are visible or invisible today have been formed, and show different functions. Therefore, strictly speaking, the word tail is relative to vertebrates with this "pillar", while invertebrates such as scorpions also have a "tail" called tail, but it is a fake after all.
Why is the giant panda a national treasure
The scientific name of giant panda is actually panda. It is very rare. It is one of the most precious animals in the world. It is a national first-class protected animal with black and white body color. Giant panda is a unique species in China. The existing main habitat is in the surrounding mountainous areas such as Sichuan and Shaanxi, which is known as "China's national treasure".
The scientific name of the giant panda is actually "Panda", which is very cute. He has thick white hair on his round head and black hair on his head. He has a pair of round ears and big eyes on his face. There is a circle of black hair around his eyes, like wearing a pair of sunglasses and a big mouth on his face. He has white hair on his fat body and four short and thick black legs. He walks slowly. He is simple and honest, naive and lovely. Giant pandas are fat and big, and have a big belly, so they can eat very much. They have to eat a lot of food at a time. Its stomach cannot digest fibrous food and can only absorb nutrition from the juice and water of food. It also likes to drink clear spring water. The hometown of giant pandas is in the high mountains in the southwest of China. There are green bamboos everywhere and springs everywhere. Therefore, the main food of giant pandas is bamboo and springs.
Giant pandas are living fossils. A long time ago, the climate on the earth became colder and colder. Many large ice cubes were formed on the earth, and plants could not grow. Many animals froze to death and starved to death. Only the giant panda survived in high mountains and deep valleys and became a treasure of the animal world. So far, the giant panda still retains the characteristics of ancient animals. Over thousands of years, many animals have changed, but the giant panda is still the same as before. Therefore, it is not only loved by adults and children in appearance, but also a "living fossil" for biologists to study ancient creatures. Giant pandas are also sent to Japan, Britain, the United States and other countries as friendly envoys of the Chinese people. When giant pandas arrived in those countries, they were warmly welcomed by adults and children. They cherish the giant panda very much, give it delicious food, let it live in a beautiful house, give it a nice name, what Huanhuan, Zhenzhen, Dongdong... Such lovely and precious giant pandas are unique to China in the world, so we call the giant panda China's "national treasure".