Deep-sea creatures have scientific research value. Why are their structures weird and scary?

The shape of an organism is determined by genes, and genes are influenced by the environment. Under the condition of natural selection, genes with better adaptability can be preserved. So the biological form is caused by the environment to a certain extent. In this article, I won't discuss the effects of various environments on genes, which is not my specialty. I will discuss the morphological characteristics of organisms under high pressure from the perspective of mechanical environment. Anyway, in the deep sea, you are ugly and can't see other fish.

1. Water pressure in deep-sea environment

The water pressure is positively related to the depth, and the deeper the water depth, the greater the water pressure. The formula is as follows, in which the density and gravity acceleration g are also related to the height, but the value changes little and is ignored here. According to the formula, the depth of the deepest Yana Trench in Mali can reach 1 1 km, and the bottom water pressure is 1 10 MPa. The normal atmospheric environment of human body is 1 atmospheric pressure, which is 0. 1MPa. It can be seen that the water pressure in Yana Trench is 1 100 times of the comfortable atmospheric pressure of human body. In such a high-pressure environment, the human body can't bear it anyway.

The water depth of more than 500 meters in the world is in the deep sea area, where the water pressure is about 5 MPa, or 50 times of atmospheric pressure.

2. Morphological characteristics of deep-sea fish

Deep-sea fish are characterized by big mouth, big eyes and light weight. Externally, extremely ugly. Deep-sea anglerfish is shown in the figure below. Teeth staggered, with a light on your forehead? Small lanterns? He has a big mouth on his cheek.

Of course, the above-mentioned deep-sea fish are all located in the deep seabed and live below the middle layer of the deep sea (1000 meters below). In this range, the sun can't penetrate and the deep sea is dark. The water pressure exceeds 10 MPa, which is 0/00 times of the standard atmospheric pressure.

3. The relationship between mechanical environment and morphology

In the deep sea where the water pressure exceeds the standard atmospheric pressure 100, the high-pressure environment is a remarkable feature of deep-sea creatures. In the high-pressure environment, on the one hand, the cells of deep-sea creatures bear higher pressure, on the other hand, the shape and structure of fish also ensure better endurance.

The picture above shows the skeleton of deep sea fishing. In fact, as far as bones are concerned, it is calcium, and the load-bearing capacity is still relatively large. Relatively strong bones, such as human femur, have a maximum compressive stress of 170MPa (below). Even if they are thrown into the Yana Trench, Mali will not be crushed. So there is no problem in terms of bone compression alone.

However, the high ultimate pressure of bone material itself does not mean that the structure itself is in a good stress state. As far as the structure is concerned, stress concentration is easy to occur in discontinuous places, so the cross section of fishbone is similar to a circular cross section, and the pressure distribution is as uniform as possible. This effect is also reflected in the shape of fish. For example, the fish's mouth is an arc-shaped bone, not a triangle, just to reduce stress concentration.

After the basic shape of the skeleton is determined, the fish is below. We found that those ugly deep-sea fish are fatter, as shown above. The circle is actually to disperse the pressure of water on the body. Such a fat fish won't feel particularly tired (stressed) somewhere in the body. Even a scrawny fish, its cross section is approximately circular. Of course, this kind of fish has a big disadvantage: it can't swim fast. Unlike that kind of flat fish, it can quickly shuttle through the water, as shown above. This flat body can minimize the resistance of water and make fish swim faster.

Fish in the deep sea probably don't prey by speed, because the dark deep sea can't be seen clearly at all. These fish will catch fish in another way. This is why many deep-sea fish bring their own lanterns. Is to attract food with a light-emitting device and then open your mouth and swallow it.

4. Summary

Deep-sea fish live in the sea below 500 meters, and the deeper and longer the fish, the uglier it is. Most of those ugly deep-sea fish are below 1000 meters, and the water pressure is 100 times higher than the standard atmospheric pressure. Under such a huge water pressure, the fish's body grows as round as possible, thus distributing the water pressure evenly throughout the body.