Man and tennis together for a long time

2001/04/04 Carton Virto, Eider - Elhuyar Zientzia

• Eboluzioa
• Zoologia
• Osasuna

Tennis are internal parasites of vertebrates, they live in the intestine when they are adults and are usually transmitted to humans by poorly cooked meat. Tennis is hermaphroditic and its life cycle is complex. To begin with, a worm is not born and dies in the same hostel. An adult tapeworm can definitely reside in the gut of the host for 15 years, usually a mammal, including the man, located at the top of the trophic chain. The eggs laid by the tennis are expelled with feces and, next to the grass, end in the intestine of some mammal (pig, rabbit...). But the parasite will not reach maturity, as this mammal is a mere intermediary. Eggs pass through the intestinal walls of the pig or from which it comes, reach the muscles through the blood and cause a muscle cyst. The cyst continues muscularly until a hotelier eats the mediator. Then it will become a worm in your intestine.

As old as man

There are several tennis species. The best known are the genera Taenia, Dibothriocephalus and Echinococcus. Some contaminate man and cows, others man and pigs, others dogs and rabbits, and also those that are transmitted from fish to vertebrates. It is therefore an extensive family.

American researcher Eric Hobe of the Department of Agriculture has researched the anatomy of several tennis species and published a novel theory on the evolution of worms. In his opinion, the pigs and cattle of the houses captured the parasite of man in three historical stages and not the other way around, as previously thought. That is, hominids have had tapeworms for a long time in their intestines and when they domesticated livestock, about 10,000 years ago, they transmitted it to them.

And who transmitted tennis to hominids? The closest to the tennis worms captured by humans are those that contaminate lions and hyenas in Africa, which they receive through the flesh of antelopes. It is therefore possible that our ancestors have also been contaminated by the intake of antelope or by excrement of antelope or other animals. Moreover, ancient hominids were not only predators, but also prey, and perhaps with them the hyena and the ancestors of lions rose.

Although it is not clear who handed down tennis, Hobe has indicated that the tenor family tree can teach us what the ancestors of man ate, and that it can give us clues as to where and when they started eating meat. In fact, it is believed that hominids began eating meat about 2 million years ago, coinciding with the appearance of the genus Homo. But that is not clear either.