Life has a beginning and an end, which is the most basic fact, and at the same time a very important natural law.
We always hope that life can last indefinitely, but we do not know that death is precisely for the sake of the eternal survival of the entire population, and the so-called eternal life may bring disaster to the population. This is because an immortal life form cannot guarantee genetic diversity. What is genetic diversity?
For a life form, genetic diversity refers to genetic differences between different populations or between different individuals in the same population. For living organisms, the living environment provided by the earth is in constant flux, when adverse changes occur, due to the existence of genetic diversity, some individuals in the population can better adapt to the unfavorable environment, thereby surviving, which also ensures the continuation of the population.
For populations that have lost their genetic diversity, their dependence on the environment will be very high, and if the living environment is adversely altered, it is likely to lead to the overall extinction of the population.
Sexual reproduction and death are important for maintaining the genetic diversity of a species, just imagine if human beings were immortal, then human ancestors could not survive in the changeable natural environment, let alone evolve wisdom and develop civilization. We lament that human beings cannot live forever, but we all know that if human beings are immortal, then I am afraid that before you and I are born, the human species will have already disappeared from the earth. It is precisely because of this that all life has a beginning and an end. But there is one life form that seems to be an exception, the lighthouse jellyfish.
The lighthouse jellyfish is a beautiful little animal that is at the bottom of the food chain and is very unremarkable.
But this little animal has an ability that everyone envies, that is, eternal life. It seems inappropriate to say that the lighthouse jellyfish has the ability to live forever, and it should be accurate to say that it should be rejuvenated. Yes, lighthouse jellyfish have the ability to rejuvenate.
Throughout the life of the lighthouse jellyfish, it can be roughly divided into two stages, the first stage is the juvenile period, called the hydra body; the second stage is the adult stage, which we call the jellyfish. Originally, after infancy and adulthood, it is aging and death, but the lighthouse jellyfish can achieve reverse growth, and when they feel that their life is not complete enough, they will return to the hydra body and start again.
If an old man in his sixties and seventies can go back to his twenties and thirties, it is absolutely a fantasy, but the lighthouse jellyfish can do it, and the process can be repeated indefinitely.
The immortality of lighthouse jellyfish seems to be contrary to the laws of nature and is not conducive to genetic diversity. In fact, not all lighthouse jellyfish will perform the stunt of rejuvenation, and the lighthouse jellyfish itself is also a sexually reproducing animal, under normal circumstances, the lighthouse jellyfish will go through infancy, adulthood, and then reproduction, and finally to death.
But if the survival of the lighthouse jellyfish is challenged, the process will be disrupted, and the lighthouse jellyfish will abandon the process of gender reproduction in favor of asexual reproduction. The process is a lot like rejuvenation.
The lighthouse jellyfish in adulthood will transform itself into a sac, which after development will become a hydra group, this hydra group will develop into an infinite number of hydra bodies, and the hydra body will eventually develop into countless real lighthouse jellyfish.
So in essence, the rejuvenation of the lighthouse jellyfish is not really rejuvenation, it is just a clone-like asexual reproduction, which decomposes itself into countless small jellyfish like itself. Since the lighthouse jellyfish itself is not truly immortal, and under normal circumstances it is intersex reproduction, it does not violate the laws of nature and does not affect genetic diversity. And the lighthouse jellyfish, as a creature at the bottom of the food chain, has a very high accidental mortality rate.