Chapter 2 jellyfish and snail

These days, we seem to be more self-conscious about ourselves than ever.In fashionable magazines, there are numerous articles advising us to do this and that to ourselves: how to find ourselves, confirm ourselves, cultivate ourselves, protect ourselves, what's more, on some special occasions such as weekends, we need to Learn how to temporarily forget yourself.There are many instructive books, best sellers, on self-actualization, self-help, self-improvement, and self-development.Groups of self-respecting people pay exorbitant fees to attend three-day short courses on self-awareness.In college, electives on self-enlightenment are available.

Reading this, you might think that we are only recently discovering ourselves.We have long suspected that there is something alive there, ruling the field, separate from everything else, absolutely individual, absolutely independent.At this moment, it has finally been sealed with a real name, proclaimed to the world, it is called self. It's an interesting word that has been around for a long time.Its social meaning is more ambiguous than you might imagine.The original root, se or seu, is only a third-person pronoun, and most of its descendants, except self itself, are made to imply someone else, who is in some sense related; sibs (blood relatives) and gossips (close friends) both come from seu. Se has also been used to refer to something external or separate, hence the words separate, secret and segregate.An expanded root of it, swedh, entered Greek as ethnos, meaning of my kind, and ethos, meaning the customs of these people. Ethics (ethics, morality) means the behavior of people who belong to my race and have similar ethical concepts.

We tend to think that we ourselves are the only completely unique beings in nature.But that's not the case.Uniqueness is an extremely common quality in the biological world, and it is not really unique.A phenomenon cannot be both unique and universal at the same time.Unique, even individual, free-swimming bacteria can be considered distinct entities, distinguishable from each other even if they are descended from a single clone.Spudich and Koshland recently reported that individuals of the same species of motile microbes behaved differently, resembling a eccentric with eccentric behavior.When they are looking for food, some will move crookedly in one direction, travel for a precise few seconds, and then stop abruptly; while other bacteria will travel in different ways, travel differently, but each has a definite number. time.If you catch their flagella, hang them on the surface of a slide coated with a layer of antibody, and observe carefully, you can distinguish them one by one by the way they twist their bodies, and the distinction is so accurate, It seems like they each have different names.

Beans carry self-marking tags so distinct from each other that a mouse is marked by its scent.These tags have glycoproteins, they have lectins, and they may be related to some kind of internal, crucial negotiation.This negotiation is about the attachment relationship between beans and nitrogen-fixing bacteria.Helium-fixing bacteria live in the plant's skin, embedded in its root nodules.Phytohemagglutinins from one line of beans have a special affinity for the surface of a particular fungus that colonizes that line, but not for fungi from other lines of beans.The design of this system seems to be to maintain some exclusive partnerships.The natural world is made up of such small snobbish gangs.

Coral polyps also have biological self-awareness.If you put polyps of the same species together and let them touch each other, they will fuse into one polyp, but if they are of different species, they will repel each other. Fish can distinguish the same species as individuals by their respective smells.Mice can do the same.This olfactory discrimination is regulated by the H2 locus.Genes for immune self-labeling are also contained within the same H2 loci. The only living individuals that seem to have no sense of privacy at all are those nucleated cells separated from their mothers and placed in petri dishes.Given the chance, under the right conditions, two cells from wildly different sources, say, a yeast seedling cell, a chicken red blood cell, will touch, fuse, and those two nuclei will fuse, and then, this new The hybrid cells will vigorously divide and produce a large number of offspring.Bare cells lack self-esteem and seem to have no sense of self at all.

The markers of the self, and the sensory mechanisms responsible for recognizing them, have traditionally been seen as maintaining one's individuality for one's own benefit.With this mechanism, an organism is able to defend itself and protect itself from all other organisms.From this point of view, self-nature is conducive to self-protection. However, in real life, things are not like this.The self-marking mechanism of marine invertebrates must have been perfected long before the evolutionary process reached us.The establishment of this mechanism is to allow one kind of organism to find other organisms, but not for predation, but for the establishment of symbiotic families.Sea anemones that live on crab shells are extremely picky about choosing a mate.So are crabs.Only that one kind of anemone can find that one kind of crab.They felt each other unmistakably, and lived together as if they were made for each other.

Sometimes the different selves are so entangled that two organisms, attracted by each other's molecular configuration, will merge the two selves into a single organism.The best stories I've heard about this are about nudibranchs and jellyfish in the Gulf of Naples.That nudibranch is a type of marine slug.At first glance, it was found to be carrying a small underdeveloped parasite, resembling a jellyfish, permanently attached to the ventral surface of the nudibranch's mouthparts.Out of curiosity, some marine biologists explored how the jellyfish got there.They first scoured the adjacent seas for its early developmental form, and they made a startling discovery.The attached parasites, though apparently specialized and renouncing solitary life, are actually able to reproduce, because they are more numerous at certain times of the year.They drifted in the upper water layers and grew surprisingly well, eventually becoming full-fledged, decent-looking normal jellyfish.At the same time, that snail also gave birth to young and began to grow normally, but not for a long time.At a very young age, they are caught by the jellyfish's tentacles and engulfed in its umbrella-shaped body.At first glance, you might think that the jellyfish is now the predator and the snail is its prey.In the previous life, he was humiliated and humiliated, and was inferior to others, but now he is repaid, and he is proud.But no.Not only was the snail not digested, but it was also insatiable. It didn't take long before it began to bite back.The jellyfish's radiant tubes are eaten first, then its periphery, and finally its tentacles, until the jellyfish is essentially eaten and the snail grows accordingly.In the end, the relationship between the two returned to what we saw at the beginning. The nudibranch was swimming around and dangling, but there was nothing left of the jellyfish, only a successfully processed round parasite , attached to the epidermis near the snail's mouth safely.

Picking this story, I already feel at a loss; thinking about its meaning is even more confusing.Both creatures came into the world for this encounter, each bearing their own markings so that they could find each other in the waters of the Gulf of Naples.This collaboration, if you want to call it that, is completely specific.Only this species of jellyfish, and only this species of nudibranchs, can come together and live like this.And, even more amazing, they can't live any other way.They can only survive if they depend on each other.They are not real selves, they are plainly alien. Thinking about these things gives me a weird feeling.They don't remind me of anything I've ever seen.Really do not have.I have never heard of such a cycle of life.These things are outlandish.That's right, it's weird.And at the same time, like a vaguely remembered dream, they reminded me of the whole earth at once.As a result, my heart was churning, I could no longer be calm, and I couldn't understand it.