Scientifically, parasites are creatureswhich penetrate into other organisms and use their vitality for their own survival. These include fleas and lice that live on the bodies of the "owners" and suck their blood. There are also roundworms that can be picked up by eating raw meat - they will live in the digestive system, pick up nutrients and grow to enormous size over time. Today, science knows a huge number of parasites, but when exactly they appeared on our planet and which creatures were the first to come up with such a way of life, scientists are still not clear. Fortunately, thanks to the hard work of Chinese scientists, the veil of secrecy slowly began to be removed.
What is parasitism?
Recently in the science journal Nature Communicationsan article was published in which one of the first acts of parasitism in history was described. This term is understood to mean a phenomenon when the body uses a foreign body to support its life. It's kind of symbiosisHowever, creatures do not receive mutual benefit -with parasitism, only one organism benefits and develops, while the other feels a lack of nutrients and gradually weakens.
Symbiosis Is the interaction of two organisms, whichbrings mutual benefit. For example, a collaboration of bees and plants can be called a symbiosis, when insects pollinate flowers and help their reproduction, and flowers are for them a source of nutritious nectar.
Inside a person, parasites can also live, and oneof the most famous is bull tapeworm (Taenia saginata). This worm can enter the body with poorly processed animal meat and subsequently absorb nutrients entering the human body. The length of an adult bull’s tapeworm can reach 10 meters. During the stay of the parasite in the digestive system, a person develops a disease of teniarinhiasis. Its symptoms are attacks of pain in the abdomen, a feeling of mobility inside, nausea, headache and a frequent feeling of hunger. Man clearly lacks nutrients, because most of them are taken by the parasite.
Fleas, lice and roundworms are modernparasites. It is logical to assume that they had an ancestor who came up with a parasitic lifestyle. Most likely, it was some kind of tiny worm, which is the main difficulty in finding it. The fact is that the worms do not have a skeleton and other relatively rigid parts of the body, so time did not spare them and their remains simply have not survived to this day.
See also: What parasites live in the carpet?
The remains were not preserved, but who said thatancient parasites could not leave traces? Recently, Chinese scientists managed to find the remains of ancient invertebrate creatures, referred to as brachiopods (Neobolus wulongqingensis). They are also known as brachopods and outwardly resemble mollusks, and their habitat is cold water. Today they can rarely be found anywhere, but millions of years ago they were almost at every step.
Brachiopods were attached and are attached to the bottom withspecial stalk - all this is clearly shown in the video below. Scientists found traces of parasites on fossil remains that attached to shells and brazenly stole nutrients from brachiopods. Researchers believe that infected organisms felt a lack of these substances and could not grow to large sizes. Healthy organisms developed normally. Signs of parasitism are evident.
It is believed that some of the very first parasiteslived about 540 million years ago - scientists came to this conclusion based on the age of the remains of a marine fossil. We can say that parasitism arose in the Cambrian period, during which modern groups of animals began to appear. My colleague Ilya Hel wrote about this important moment in the history of life on Earth several years ago - I recommend reading his article.
Here's another interesting topic: 8 unsolved mysteries of the Earth
Perhaps the parasites that left behind themfar from the first to come up with a way of life so oppressive to victims. It is only clear that parasitism as a phenomenon has greatly influenced the evolution of living creatures. This is a peculiar butterfly effect - if once parasites had not prevented living creatures from developing, evolution would have proceeded in a completely different way and today's animals would not have looked like they are now.
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Parasites are able to use for their own purposesalmost any creature. On this subject, I recommend that you read the article that Lyubov Sokovikova wrote - in it she told what parasites lived in the feathers of dinosaurs. It turned out very interesting!