Silver candle autumn light, fan fluttering fireflies
Yes, when it comes to glowing in the biological world, people first think of fireflies.
However, in addition to this insect, there are many organisms that can also emit light, such as for some fish living in the deep sea, luminescence is a means of making a living.
Fishermen who work offshore at night and those who live on the sea often see light bands on the surface of the sea, which are emitted by some algae, and when they are disturbed or multiply, it seems that the ocean is burned. Children who play on the beach at night can find sand silkworms on the beach, which is also a luminous animal. In addition, jellyfish, corals, certain shellfish and worms can emit light.
It has been found that different organisms emit different colors of light: all plants emit a very dim red light when exposed to sunlight, microorganisms generally emit a faint blue or green light, and some insects glow yellow. Carefully divided, the luminescence of organisms can be divided into two categories: one is passive luminescence, such as plants, those faint red light is just the extra light that has not been able to participate in photosynthesis, whether this light has biological significance for plants is still a mystery, but the general view is that this light is meaningless, just like the material coated with fluorescent substances that emit light after strong light illumination; the other is active luminescence, although there are some luminous meanings that have not yet been fully understood, but one thing is certain - This luminescence is useful for the vast majority of active luminescent organisms.
Light is an energy, and active luminescence is a consumption of energy. The survival strategies of living organisms have one of the most basic commonalities, that is, to maximize energy savings in normal activities that sustain life, so active luminescence must be an important part of the survival of these organisms. It is necessary to say that some animals do not emit light themselves, but in a symbiotic environment they use the light of luminous bacteria to serve themselves, as we will mention in the following example.
Luminescence is a biological behavior, specifically a biological communication. Let's take a look at what active luminescence can do for luminous organisms.
The first thing people think of because of fireflies is that glowing is the courtship behavior of animals
。 The female fireflies emit a faint glow and lurk in the grass, and the male will show favor with a bright flash of excitement when she finds it, and then wait for the female to change its glow to determine how sure she is of success.
Warnings are also a use for light. It is well known that many species of animals have an area of their own food source, and this order is based on the natural tacit understanding of the same species of organisms. In order not to exacerbate the contradiction, the animals usually have a set of warning methods, such as certain luminous fish on the deeper seabed.
There is a fish in the deep sea called the trout, which has a light emitter on the top of its head,
It is used to confuse some of the small animals that pass by it. If an animal has too much curiosity, then this vice, which cannot resist temptation, is likely to make it the ghost of the mouth of the trout. This luminescence is one of the feeding behaviors. Interestingly, the trout doesn't glow on its own, but the protrusion above its head provides a living environment for a glowing bacterium, which gets a stable source of life, while the trout uses the light they emit to attract small animals.
In 1885, Du bauis pointed out that the glow of fireflies was a chemical reaction, and later, scientists got the gene for luciferase. After the research of scientists, the principle of glow of fireflies has been completely clarified.
We know that chemiluminescent substances have two energy states, namely the ground state and the excited state, the former has a low energy level and the latter has a high energy level. In general, molecules have high and unstable energies in the excited state, and they easily release energy back into the ground state; when the energy is released in the form of photons, we see bioluminescence. However, if we try to make an object emit light, we only need to give it enough energy to change it from a ground state to an excited state, and bioluminescence requires the participation of enzymes in the organism. Enzymes in living organisms are highly efficient catalysts that induce chemical reactions that energize luminous substances in a least consuming manner. In fireflies, the energy produced by the hydrolysis of triphosphoadenoside (ATP) causes the fluorescein to oxidize, so that for every ATP decomposed, a photon is produced, which emits light. The vast majority of bioluminescent mechanisms are known to be this pattern. But in luminous coelenterates, fluorescein is replaced by photoproteins , such as green fluorescent proteins in common luminous jellyfish , which emit light by reacting with calcium or iron ions.
Above we said that bioactive luminescence is ultimately a communication behavior of living things. Some animals with eyes can directly capture light from similar species, but how do some creatures without eyes achieve light communication? Scientists have conducted some meaningful experiments in this regard, so let's take a look at those that have universal significance.
First of all, bioluminescence is the most economical, so more bioluminescence is a very weak light, so weak that the human eye cannot see and can only be detected by instruments. Like water fleas, we don't even know that they are also an active luminous animal. In order to detect their faint light, scientists filled them with water in quartz glasses that do not absorb ultraviolet rays, and then put in some water fleas; the test assumed that the individual luminescence of water fleas was independent, which meant that the light they emitted could be superimposed, and the more water fleas there were, the stronger the light. But the results of the experiment were unexpected, and when the number of water fleas reached a certain proportion, this superposition did not exist, and the light weakened.
Studies have found that this was originally an optical phenomenon called "coherence". In the study of the active luminescence of tiny organisms, scientists have also found that abnormalities in the body of luminous organisms can also affect the quality of luminescence. Light-induced delayed luminescence is also present in luminous organisms, and coherence has been found in studies. So people have proposed a hypothesis called "coherent electromagnetic field and biophotons", which holds that in organisms that can actively emit light, there is a coherent electromagnetic field to release biophotons, which is the basis of cell communication in living tissues, that is, cells and cells can use electromagnetic fields and light to transmit information. This is the visual system of the cell.
In 1993, Russian scientists demonstrated through another experiment that cells may have "vision." The experiment went like this: two groups of breast tissue were placed in a lattice for culture, one group (AB) separated by an opaque separator and the other (CD) separated by a transparent separator; different hormones were added to the AB to measure the secreted proteins, oxides, and chemiluminescence. The experimental result was that there was no change in AB and no change in CD, indicating that they were aware of the light emitted from AB. The scientists then did a similar experimental study with neutrophils, and the results were the same.
These research efforts are very meaningful, on the one hand providing encouraging clues for us to solve the mystery of transmitting information between biological systems, and on the other hand, providing an imaginary space for scientific explanation of the origin of animal vision.