Cockroaches are known as the undead Xiaoqiang, and everyone thinks that it is the most tenacious animal in the world, but in fact, one foot can end the life of a cockroach. Compared with cockroaches, planarians are creatures that can never end their lives with one foot, and even if they are chopped into slag, they can grow again.
So, what exactly are planarians? How strong is its regenerative ability?
Planarians
Planarians are the general term for the animals of the flattened animal planarian class, its number and variety are diverse, the requirements for the growth environment are simple, as long as it is clean water, whether in the sea or in fresh water, it can grow. Common planarians are mostly gray, brown or yellow, and they rely on muscle contraction and ciliary oscillations to swim in the water, while planarian cilia mostly grow on the abdomen.
Although planarians are flat animals, people are named because planarians cause water to swirl when they move. The eyes of the planarians are on the back of the head, and because the eyes of the planarians have no crystals, they cannot be imaged, only visual perception.
The evolutionary status of planarians is not high, but compared with other organisms with high evolutionary status, its sensory organs and nervous system are extremely developed, and through perception, they can respond quickly to changes in the external environment. Planarians are hermaphrodites that can be bred by allogeneic mating or by segmenting the body.
The gecko survives in distress and breaks its tail, its regenerative ability is only limited to the tail, and the planarian, even if it encounters danger and is divided into n segments, can grow again, and the regenerative ability it has is called "heartbreaking madness".
In 1898, in order to challenge the limit of planarian regeneration, the American biologist Morgan studied planarians in the laboratory, and once cut a planarian with 279 knives, and a small planarian evolved into a pile of broken flesh, which was thought to be the limit of planarian regeneration, and the planarian completely lost its life. But planarians survived again on the few genetic tissues left in the broken flesh, and regenerated perfectly, and the fragments cut into pieces relied on their own regenerative ability to form new life forms.
After witnessing such a super regenerative ability, many scientists rushed to challenge the regenerative ability of planarians, some cutting the limbs of planarians, and some separating the heads of planarians from the body, but after repeated challenges, everyone found that the regeneration genes of planarians are really very powerful, almost unlimited growth.
The reason why planarians are chopped into minced meat and do not die, and form new life forms, is because of the super regenerative ability of planarians. The great regenerative capacity of planarians is due to the cell population called "neoblasts" contained in the body of planarians, which have the potential to proliferate and differentiate.
"neoblasts" are also known as stem cells of planarians, and these stem cells work in two groups in the planarian gland, one is called adult stem cells, which are responsible for regeneration and tissue renewal, and the other is called reproductive stem cells, which produce germ cells when planarians undergo sexual transformation.
In planarians, these stem cells, which can proliferate and differentiate, account for a quarter of the total number of planarian cells. So whenever the planarians themselves are damaged, these stem cells in the planarians will proliferate and evolve into other types of cells needed in the planarians. As long as the stem cells remain in the body of planarians, planarians can reorganize new cell tissues and perfect their missing organs.
The powerful regeneration ability of planarians is enviable, but in addition to planarians and geckos, there are many animals in the world that have regenerative ability. So, which other animals have the ability to regenerate?
Regenerative ability of living organisms
Although the ability to regenerate is very incredible to humans, in nature, there are still many animals with regenerative ability, but most of these animals with regenerative ability are inferior animals.
First of all, we must talk about animals with regenerative ability, in addition to geckos and planarians, we must talk about earthworms. Earthworms are not as regenerative as planarians, but they are much better than geckos with long tails.
Earthworms are able to regenerate bodies, and when the earthworm's body is divided into two segments, the muscle tissue on the earthworm's body section contracts and dissolves itself to form new cell clumps. When these cell clumps combine with the protocellular cells in the earthworm's body, they form regenerative buds on the section and gradually grow new bodies.
The "broken wrist regeneration" of octopus is also very worth mentioning. Octopus, also known as octopus, is cruel and aggressive, and even eats itself when it is fierce. Because octopuses have many claws, in the winter, octopuses that dive into the seabed will nibble on their claws in order to survive, and these claws will grow in the following year.
In addition, octopuses will survive like geckos when they encounter danger. The difference, however, is that geckos have only one tail, while octopuses have many claws. In case of danger, the octopus will use its own tentacles as bait to confuse the enemy through the squirming of the broken claws and take the opportunity to escape.
Planarians are able to grow again with almost a little limb, and their regenerative ability is almost unlimited. And like it, which can regenerate indefinitely, there is also a creature called the salamander. However, unlike the infinite regeneration of life of planarians, the infinite regeneration of salamanders is only reflected in the regeneration of severed limbs.
When the salamander is injured, its epidermal cells seal the wound and allow the wound to heal quickly, but allowing the wound to heal is not the most distinctive feature of the epidermal cells. Its most distinctive feature is the coronal protrusion formed by epidermal cells, which drives the activity of other cells in the salamander's body, and finally derives new limbs.
There are so many creatures in the world that are capable of regeneration, so can we humans use the regenerative properties of living things for human treatment?
The regenerative ability of living things allows human beings to see the hope of regeneration. If humans can achieve regeneration, then when there is a problem with human organs and limbs, through regeneration, humans may really be able to achieve zero death, so that all people can live forever.
As a higher animal, humans, like many animals, the human body also has regenerative genes. It is only because human evolution is relatively high that the regenerative function of the human body is not obvious, but each body part is spending time to show its own regenerative function.
Such as human hair, these hairs are the most vivid display of the regenerative function of the human body. After each shaving of hair or body hair, after a period of time, new hairs will grow, and unless the person's body functions age, these hairs will continue to grow.
Many animals have amputated limbs and regenerated meat, which actually stimulates the cells in the body that have proliferation, differentiation and repair. And these organisms are not as fast as humans, and the maturity of cells in the body is not perfect, so it is very easy to stimulate regenerative functional cells. And human genes have been evolved, the body's cells with regenerative function, in fact, slowly transformed into repair function cells, so it is very difficult for humans to achieve limb regeneration like salamanders.
However, in the future, it is not impossible to stimulate regenerative functional cells in the human body. At present, we have not yet captured regenerative gene cells in the human body. It is because science and technology, medical means can not meet the needs, and the future, with the development of the times, I believe that one day, human beings can finally find the mystery of regeneration.
Bibliography:
Superman and the Planarian. CHEN Chongwei. Middle School Students Today.2014-04-10
Research progress of planarian regeneration. Mark Science. CHEN Guangwen. Max. Biology Teaching.2008-01-08
Research progress of planarian stem cells. WANG Songtao; CHEN Guangwen; Xu Cunzhao; ZHANG Jingbo. Basic Medicine and Clinical.2009-01-15
Author: Si Wei Proofreader: Xiao Wan