How do animals know the time? What critters know the time

Animals do not have a concept of time, but rather an instinct or reflex of biological inheritance.

There is a peculiar farm in California, USA, where more than 100 donkeys are workers, and they do all the farm work there. Interestingly, all the donkeys stop working automatically at noon, and by 12 noon, no one can force them to continue working. And by 6 p.m., they're back to work.

In addition to this, the animals also know the schedule, and the swallows go on a "long journey" every year. In winter, swallows fly south to the South Sea Islands, India and Australia to "take refuge from the cold"; In the spring season, they go north in groups, in early spring and February, they fly to China's Guangdong, in March to reach Fujian, Zhejiang and the lower reaches of the Yangtze River, and in early April you can see their traces in Qinhuangdao.

It is now known that there are many kinds of biological clocks: there are day clocks that correspond to day and night, tidal clocks that correspond to the tides, and annual clocks that correspond to the earth's revolution and seasonal changes. It is these biological clocks that allow animals to live, forage and move normally in nature.

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All animals on Earth have a physiological mechanism called the "biological clock", which is a 24-hour cyclic rhythm from day to night, such as a light-dark cycle, which coincides with the rotation of the Earth.

All living things have a certain rhythm of biological clocks, which are actually formed in the process of evolution, and are essentially related to the geomagnetic field.

It's simple! I've been living with humans for n years, and I'm used to it!!

Biological clock, looking at the sun, illumination.

Circadian clock + heredity + external environment.

Many creatures have their own biological clocks, just like a rooster crows in the morning, and their brain tells them some specific times, which of course cannot be as accurate as a human looking at a watch.

We are all here, you don't understand, I don't like people, don't you treat others badly! You don't.

Animals: 1. Pigs, cattle and sheep: active during the day.

Begin to fall asleep at night. 2. Cats: Sleep well during the day.

The night starts to come alive. 3. Flying squirrels: stay in tree hollows during the day, and only come out to move after the sun sets.

4. The birds also "get up" on time. 5. The rooster crows, then the ducks wake up, then the sparrows wake up, and the ducks wake up. 6. Pulsatilla.

They like to sleep lazily, and the golden sun has already shone on the earth, and they slowly let go of their singing. 7. The crab hides in the dark during the day, and the color of its body will become darker; At night, when they are active, the color of their bodies becomes lighter. 8. Cockroaches are particularly active in the evening.

Scientists put cockroaches in a dark cage and found that their activity cycle is 23 hours and 53 minutes, which is very similar to the rotation period of the earth! Plants: 1. In South Africa.

There is a large-leaved tree whose leaves turn every two hours, so the local residents call it the "living tree clock"; in South America.

In Argentina, there is a wildflower that can tell the time, and it blooms around 8 p.m. in early summer, known as the "flower clock". 2. Morning glory.

Be sure to bloom early in the morning, gourd and evening primrose flowers must bloom at night, and there are many other types of flowers that also bloom at specific times. If we investigate the flowering time of various plants, we may be able to make a clock with flowers indicating the time.

As early as the 19th century, many fossils of marine animals dating back 500 million years were excavated, and it was thought that these animals were the earliest creatures. But Darwin was skeptical, because according to the theory of evolution, life must have a gradual evolutionary process. You can't just be a simple algae yesterday and suddenly pop up so many complex animals today.

There must be something relatively more primitive between them that connects them.

In 1947, in the Ediacara region, north of the Adelaide Mountains in southern Australia, a number of round, jellyfish-like imprint fossils were discovered. Later, it was determined that these fossils, known as the Ediacaran fauna, were produced between 500 million and 600 million years ago. At the Paris meeting of the International Union of Geological Sciences held in 1974, the Ediacaran fauna was unanimously recognized as the Late Precambrian, which is one of the oldest metazoan fossil groups found on Earth.

The discovery and study of the Ediacaran fauna greatly promoted the development of Precambrian paleontology and advanced animal history again.

With the further development of paleontology, scientists have a newer understanding of the earliest animals. Among them, the Steep Mountain Tuo biota found in China occupies a very important position. Chinese scientists have found animal embryo fossils about 100 million and 100 million years ago in Guizhou and Hubei, which is considered to be the earliest animal, and further pushed the time of the earliest animal to 100 million years ago.

Recently, American scientists have discovered a special organic compound in strata dating back more than 700 million years, which has been confirmed to be produced only by a certain type of sponge. And the sponge is considered to be the most primitive animal on the earth, it evolved from fungi in the ocean, and is the ancestor of all animals on the earth today. So this discovery pushes back the time of the appearance of animals on Earth to more than 700 million years ago.

Science is constantly evolving, and the timing of the earliest animal appearances will continue to be updated with scientific research.

At present, there are about 1.5 million known animal species, distributed in all seas and lands on the earth, including mountains, grasslands, deserts, forests, farmland, waters and poles, becoming an inseparable part of nature.

So when did animals appear? It is believed that the earliest ancestors of animals were sponges, which have been on Earth for at least 100 million years, and fossilized sponges dating back about 500 million years have also been discovered. So how did animals evolve step by step to get to where they are now?

The history of the animal kingdom is the long process of animal origin, differentiation and evolution, from unicellular to multicellular, from invertebrate to vertebrate, from low to high, from simple to complex.

The average gestation period for mammals is about 10 months. For example, cows, horses, donkeys, chimpanzees, etc., which are very familiar to everyone. The gestation period of kittens and puppies is only 4 months!

However, fin whales are pregnant for 11 months; The elephant's pregnancy is the longest among all mammals, 18-20 months Well, 20 months, elephant, are you swollen to survive The world's tallest mammal, giraffe 14 months gestation Kangaroo 2 months The rest of the time is spent in the bag En The shortest pregnancy among mammals is a small mammal distributed in the Inner Mongolia region of China. Its head resembles a rabbit and its body resembles a mouse, so people call it the Dahuer pika. It is about 12 centimeters long and weighs about 120 grams.

Because the hind limbs are longer than the forelimbs, there is no tail, the ears are large and oval, the edge of the ear shell is white, the back is yellowish brown from the snout to the tail base, there is a long black sand-yellow whisker on the snout side, there is a black circle around the eyes, and the abdominal hair is grayish-white. Its gestation period is only about 15 days. It's only been 15 days, dear, this guy is still very good at life, yes, I can't afford to hurt!

Why is this so? Experts tell you the answer: the structure of the placenta "determines" the length of pregnancy.

The researchers analyzed the placenta of 109 mammalian species and found that the more complex the placental structure of the mammal, the shorter the gestation period because more nutrients were provided to the embryo.

The researchers found that among the 109 mammals, the placenta of the murine was the most complex, and the pregnancy time was only 3 weeks;

The placenta of dogs and leopards is also relatively complex, with gestation periods of 2 and 3 months, respectively.

The placental structure in humans and other primates is relatively simple, so pregnancy takes longer.

Isabella Cappelini, Ph.D., Duke University, the head of the study, said

The human placenta has a relatively limited number of parts that connect maternal and fetal tissues. ”

Researchers believe that factors such as mammalian size also play a role in the length of pregnancy. Generally speaking, the larger the size of the mammal, the longer the gestational period will be.