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From fireflies to artificial luminescence

Since man invented the electric light, life has become much more convenient and rich. But electric lamps can only convert a small part of electric energy into visible light, and most of the rest are wasted in the form of heat energy, and the heat rays of electric lamps are harmful to people's eyes. So, is there a light source that only emits light without heating? Humans have turned their attention to nature again.

In nature, many creatures can emit light, such as bacteria, fungi, worms, mollusks, crustaceans, insects and fish, and the light emitted by these animals does not produce heat, so it is also called "cold light".

Among many luminous animals, fireflies are one of them. There are about 1 500 species of fireflies, and the colors of their luminescence are yellow-green, orange, and the brightness of the light is also different. Fireflies emit cold light, which not only has high luminous efficiency, but also is generally soft and suitable for human eyes, and the intensity of light is relatively high. Therefore, bioluminescence is an ideal light for human beings.

Scientists have found that the luminous device of fireflies is located in the abdomen. This light emitter consists of three parts: a light emitting layer, a transparent layer and a reflecting layer. The luminescent layer has thousands of luminescent cells, all of which contain fluorescein and luciferase. Under the action of luciferase, fluorescein, with the participation of intracellular water, combines with oxidation to emit fluorescence. The luminescence of fireflies is essentially a process of converting chemical energy into light energy.

As early as 1940s, people created fluorescent lamps based on the study of fireflies, which greatly changed the lighting sources of human beings. In recent years, scientists first isolated pure fluorescein from fireflies, then isolated luciferase, and then synthesized fluorescein artificially by chemical methods. A biological light source composed of fluorescein, luciferase, ATP (adenosine triphosphate) and water can be used as a flash lamp in a mine full of explosive gas. Because this kind of light has no power supply and will not produce magnetic field, it can be used to clear magnetic mines under the illumination of biological light source.

Now, people can get cold light similar to biological light by mixing some chemicals for safe lighting.

food chain

The chemical energy stored in organic matter in the ecosystem closely links organisms with each other through a series of relationships between eating and being eaten. The sequence in which these organisms are linked with each other by food nutrition is called food chain. According to the relationship between organisms, the food chain can be divided into predatory food chain, predatory food chain, parasitic food chain and saprophagous food chain.