For some animals, there is no need to consider this issue at all, because inbreeding does not have any effect on them at all. However, some wild animals must pay attention to the inbreeding, such as mice, sand lizards and some waterfowl. If the black-footed three-toed gull breeds inbreeding, then their offspring are very likely to die prematurely. In order to avoid inbreeding, they each have their own tricks.
The mouse can smell a special protein in the urine to identify whether other mice have close relationships with each other. Some females will leave the group after puberty to ensure that they will not be mated, and some animals will be male. Leave the group and live alone.
It is speculated that this behavior of leaving the group to breed is evolved. In this process, the offspring of the animals leaving the group have a higher survival rate, while the offspring produced by the inbred animals remaining in the population have a low survival rate, and gradually, the habit of leaving the group to reproduce is retained.
In the physics class, we learned that some of the conductors of the closed circuit will generate induced current when the magnetic flux is cut in the magnetic field. This is the conclusion of the famous Faraday experiment. After discovering the phenomenon of electromagnetic induction, Faraday suspected that the natural conductor in the earth’s magnetic field should also generate the induced current. For this reason, in 1832, under the Waterloo Bridge in London, England, the current flow under the bridge was induced current. Unfortunately, The experiment failed, and he failed to successfully detect the induced current generated by the current.
But in early 2018, the European Space Agency’s satellites detected the current generated by the ocean under the influence of lunar gravity, being dragged by the magnetic induction line that cuts the Earth’s magnetic field. This confirms Faraday’s conjecture more than 100 years ago. We also learned in the physics class, not only the magnetic energy, but also the electricity. The induced current in the ocean produces its own magnetic field, which is about one-twentieth of the earth’s magnetic field. However, this weak magnetic field will have an impact on marine life and currents, and future ocean monitoring will probably include ocean magnetic fields.
The man who took a historic step on the moon was American astronaut Armstrong, who was walking on the moon at a speed of 2.2 km/h, which is probably half the speed of human walking on Earth. But in fact, this is not the real speed of human walking on the moon, because when designing the spacesuit, it did not consider allowing the astronauts to walk on the moon. These space suits limited the speed of the astronauts to some extent.
Later, a NASA study determined that the fastest human walking speed on the moon is 5 km/h. If you walk at this speed, it takes about 91 days to complete the 10,900-kilometer lunar equator. Of course, if you can run, it will take less time, but people can’t run immediately on the moon, but they need a process from walking to running. The scientists measured the transition speed from walking to running. It is 5 km/h.
When lifting heavy objects, we can feel the pressure; when swimming in the water, we can feel the pressure; on the land, we can not feel the pressure of the air.
A standard atmospheric pressure of 101.325 kPa, when standing upright, is almost equivalent to a small car at the top of the head, but we have no feeling. The reason why we feel the pressure is because there is pressure difference, and there is also pressure inside the human body. For example, blood pressure is the pressure of blood. There is also air in the human body, such as the stomach and the lungs. This makes the internal pressure and the outside world. The atmospheric pressure is equivalent, there is no pressure difference between the two, so people do not feel the presence of atmospheric pressure. If there is no pressure inside the human body that is equivalent to atmospheric pressure, then people will be crushed and will probably become “paper people.”
In addition, there are pressure receptors on the human skin. Only when the internal and external pressures are unbalanced will the pressure receptors be excited and stimulate the brain, so that people can feel the pressure. I want to feel the atmospheric pressure and I can feel it when I fly. When the aircraft is lifted off, the outside air pressure drops, and the air pressure inside the ear is greater than the outside air pressure, causing the eardrum to bulge. At this time, you can feel the presence of atmospheric pressure.
Antimatter is relative to ordinary matter. Ordinary matter is composed of ordinary particles. Correspondingly, antimatter is composed of antiparticles. For example, an antiproton and an antielectron (positron) can form an antihydrogen atom, like electrons and protons. A hydrogen atom forming a general substance.
Most scientists believe that there is no antigravity between antimatter. According to gravitation, gravitation is the distortion of object mass to space, while the mass, life and spin of antiparticle are the same as ordinary particles, but all internal additive quantum numbers (such as charge, number of baryons, singular numbers, etc.) are Normal particles are the same size and opposite signs, such as electrons and positrons. That is to say, the anti-particle has the same mass as the particle, and its distortion to the space should be the same as the particle. Then there should be gravitation instead of anti-gravity between the anti-matter.
However, this issue has not yet been fully conclusive. There are still scientists who continue to study and hope that they can give a definitive answer.
Take a mirror and look at your face. You will find yourself with two eyes, two ears, and two nostrils. But people only have one trachea. It only needs a nostril to breathe. Why do you need two nostrils?
First of all, people belong to bilaterally symmetrical animals. With two eyes, we have stereo vision to see the exact position of the object; with two ears, we have stereo to determine the source of the sound. The two nostrils also have a similar effect, giving us a “stereoscopic sense of smell.” The mucosa in the nostrils needs to capture odor molecules, bind to the olfactory cells, and then transmit information to the brain through the nerves to produce an olfactory sense. The airflow speeds of the two nostrils are different, one is fast and one is slow. Researchers at Stanford University in the United States found that when the same odor molecule enters both nostrils, it produces different effects. One nostril smells more intense, and the other nostril smells less.
In addition, when we breathe, there is only one nostril that is mainly responsible for breathing. They are “shifted”, and one nostril works for a few hours before changing to another nostril. This is because if the two nostrils are breathing at the same time, the nasal mucosa will become dry and prone to infection, and the use of the nostrils alternately keeps the nasal cavity moist.
When the snail crawls, it will leave a transparent mucus. When the mucus is dried, it will become silver. These silvery mucus traces are the footprint of the snail. In addition to snails, cockroaches will leave the same trace.
The snail crawls very slowly and moves in a wave shape. If the foot is dry, the snail will not be able to move. There is a gland on the foot of the snail, called the foot gland, from which the mucus is secreted. This mucus is made up of carbohydrates and a protein that is “hygroscopic” that absorbs moisture from the air and keeps the mucus moist. The snail mucus is elastic. When the snail’s body exerts pressure on the mucus, the elasticity of the mucus gives the snail the power to move forward. The mucus left under the snail’s foot can not only help them move, but also be used for communication between snails, because the mucus contains some special chemicals that can leave information to other similar species.
In addition, some scientists have found that viscous and elastic snail mucus seems to have the effect of bonding injured tissue. They are studying the use of snail mucus to make synthetic glue that can repair injured tissue.