The biologist Olivia Judson: why do we need sex

Evolutionary biologist Olivia Judson is famous for his book "Every creature — for couple: Sex for survival" (published under the original title "Dr. Tatiana's Sex Advice to All Creation"). It tells the story of the sexual misadventures of animals of different species ranging from spiders and bees and ending with bonobos and manatees.

Females and males "write" doctor Tatiana (alter ego of the author) about their sexual problems, and she gives advice in the style of the magazine advice column. It's funny and interesting, but for the external lack of seriousness lurks the answer to an important scientific question: how the sexual behavior of animals affects their evolution (and Vice versa)?

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Although the book doesn't say directly about the person, we can assume that our behavior in matters of personal life obeys the same biological evolution. The Village asked a science journalist Svetlana Yastrebov to ask the author directly.

— What brings you to biology, specifically in evolutionary biology?

— If to speak frankly, in biology, I came by chance. Actually my plan was to study physics, but the plan failed and I became a student-biologist. In the process of learning, it became clear that evolution is the most interesting thing that only one can speculate.

When children are taught biology in school (at least in the US), the science they presented as a set of facts that you just need to remember, do not understand the relations of phenomena to each other. Evolution allows you to tie together disparate biological information. For example, differences in the anatomy or behavior of certain types at first seem to be just minor details that need to learn. But if you look at them through the prism of evolution, they immediately acquire meaning and can be systematized.

— "Nothing in biology makes sense except in the light of evolution" (the name of the famous report of the American evolutionist Theodosius Dobzhansky of. — Primas'. author's?)

— Exactly.

— I have a personal story associated with interest to biology and sex. Can I tell her?

— Give.

— The fact that by education I'm a biologist. And my fascination with biology began with the topic that you reveal in your book. When I was about five years old, I asked normal for a child with a question: "Where are the children?"Parents instead of a verbal answer gave me a school textbook on human anatomy. I read it entirely and since then fell in love with biology. Well, found out where babies come from, of course.

By the way, why do we even need sex? Why usually animals are of two sexes, why can't they reproduce asexually? Or be a hermaphrodite?

Biologists still argue over the answer to this question, but let's try to understand. In asexual reproduction, no sex, and the sexes either. As a result of such reproduction produces clones — exact genetic copies of the parent. For this, you can lay an egg that no one is going to fertilize (in Russian textbooks, this case relates to sexual reproduction. — Primas'. author), or to cleave in two the finger, part of which will be an independent body.

Else, like strawberries, let mustache, the ends of which new plants. Methods of asexual reproduction a great many, but in the end still get exactly the same organisms as those that gave rise to them. Of course, the offspring are not obliged in this case to look exactly the same as you, because their conditions of development can be different. But still, asexual reproduction does not involve much diversity.

Hermaphroditism is another: you have from both sexes. This means, no matter what species you ever meet, it suits you. Usually it is believed to be a hermaphrodite beneficial because you can fertilize itself. But actually, most hermaphrodites are unable to do so. The real advantage of hermaphroditism seen where the population density is low and encounters with other people occur very rarely.

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Animals of some species can change sex during life. This phenomenon is called sequential hermaphroditism. Sometimes in some circumstances it is better to be female and others male. If you want a lot of offspring, then female it is better to become at the end of life, when an animal grows to large sizes and can lay more eggs or eggs.

And if males need to guard the territory, it is more advantageous to adulthood be male, to be stronger and more impressive. But some common to all types of patterns, when it is better to have a specific gender, no, it depends on the circumstances.

Apparently, most of the animals has two separate floor for a couple of reasons. First, between females and males is "division of labor", it helps to specialize and adapt.

Secondly, after the separation of the sexes is not so easy back become hermaphrodite — especially if the animal is more complicated, as birds and mammals. So maybe someone from the "advanced" types and it would be advantageous to be bisexual, but they can not become them, because it is necessary to change the entire course of the complex embryonic development.

— That is, sexless birds and mammals does not exist?

At least, science is not known. Hermaphrodites among them, too, don't know. But there is asexual lizards and fish that change gender during life.

— A mandatory razdelyaet may be the reason that birds and animals are usually very complex sexual behavior?

— Probably. That's just a little diskriminerad biologists hermaphrodites and for some reason very rarely study their sexual behavior. But it can be as complex as the unisexual. For example, some hermaphrodite "negotiate" who gets to play the role of a female and who is male, and in what sequence. If one individual refuses to play according to the rules, the other will simply go away, and mating will not take place. What is not complex behavior?

I think we study mainly the behavior of animals and birds because they are easy to see. Especially birds: they are usually so bright, sing loudly. Yes, actually, most of the work on sexual behavior is performed on birds, because they are relatively easy to observe. And more fun than the same snails-hermaphrodites.

— How sexual behavior of birds programmed? How much it can vary?

Over the lifetime of a single bird her sexual behavior changes slowly, but over several generations — full. Modern songs of birds of the same species and the same songs a few decades ago — not the same thing. Moreover the females of some species of birds prefer males that unusual sound, not like their parents. And females of other species, on the contrary, prefer to listen to a fixed repertoire.

— Still, in birds, sexual behavior is a set of rituals, right? But in humans sexual behavior is very flexible, I think. Who is easier to find a partner — the bird, any mammal or man? I think the first two because they have clear rules.

— Well, it is very difficult to make a generalization. And, by the way, many mammals, such as primates, also have a very flexible sexual behavior, as well as people. But the main difference between humans and animals, I think, is that humans have culture, and that she first dictates the rules of conduct.

In addition, culture gives its own rituals. For example, there are people who have a fetish for certain clothing items. Fashion is changing, and some items of clothing that were popular during the Victorian era, now no longer exist. So there people with a fetish for such clothes. It can also be called plasticity of sexual behavior, and due to this plasticity of culture.

On the other hand, there are cases when sheep from birth was brought up among goats. Growing up, these sheep were preferred as sexual partners of goats, not sheep. So that animals, sexual behavior is not sewn in the subcortex, it can change the environment at least in children.


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In my opinion, studying human sexuality is incredibly difficult. On the one hand, one can ask directly what he wants, and the other people during sex is unlikely to watch, unlike animals.

And there are scientific articles that studied the sexual behavior of people? Maybe they have identified some interesting patterns?

In most of these articles are only hypotheses that cannot definitively prove. In each of the articles inspires confidence to the methods used. But, of course, some General trends in human behavior. For example, it is an unwritten rule of "man above woman." In most cultures women prefer partners above themselves, and men — on the contrary, inferior.

On the other hand, people often converge, not because I found the perfect pair, but because it was the best option available. We communicate with those near you. For example, few travels in trying to find the love of your life.

Of course, the sexual behavior of people is very flexible and is easily changed under the influence of the culture, but that's why is so difficult to understand what it really is. Culture can hide the true preferences so that the researchers, I dig. And historical data on sexual behavior are often difficult to collect.

Now it is believed that men are inclined to promiscuity (promiscuity in sexual relations), and women are more likely to remain loyal. So, this idea, at least in the West appeared only in the XIX century, and before that time thought the opposite. This is clearly seen in English poetry, written before the nineteenth century: the majority of poems in there about how often women are unfaithful to their husbands. So I wouldn't have to paddle all with the same brush and make sweeping generalizations.

Much of our visible sexual behaviour depends on the culture, and she may well not reflect the true wishes and needs of people. But they reflect a sexual fantasy, which in most cases would be completely unacceptable in an embodiment in reality. So most stores these fantasies to yourself, and they don't stay in the historical evidence.

But if you try to draw Parallels: human sexual behavior is more interesting than in other species, or is it fairly ordinary?

— I think there is an ordinary sexual behavior. Sexuality is closely associated with the evolution and in the evolution of each object is unique. If we observe nature, but they are a bright, noticeable phenomenon — for example, flowers or the birds singing — one way or another is necessary for sexual reproduction. The most violent fighting of the males, many other behavioural rituals — all this is happening for sex or for him. And here everyone ishitryayutsya. Ordinary, trivial sexuality no.

When I was collecting material for his book about sex other animals, I realized that the sexual behavior of people is only a small part of a huge range of options. And actually, I'm really glad I'm a man, not a representative of any other species. Let our sexual behavior can be a source of sadness, broken hearts, and all such things, it can bring us pleasure. But for other animals, finding a partner and communicating with them can be a very daunting task.

— Of course, the sexual behavior of people can be very different, but still most of the major religions and cultures for the monogamy faithfulness to one partner. It turns out that it generally useful?

Religion in General often seek to control sexuality. Clearly, the strategy of behavior, favorable for a group of people in General, do not always coincide with those that the individual would choose for themselves.

For me, monogamy is an extremely interesting phenomenon, and the attitude of individual people it may be very different. The desire and ability to be faithful (or unfaithful) depend on genetics, and the environment in which people grew up. Suppose, in some conditions, a certain set of genes causes the human desire to be monogamous, and in other conditions (e.g., when the environment around is constantly changing and it is not clear that will happen) gives the opposite effect.

That's just the attitude of a single person to monogamy says nothing about its objective use — or about its harmfulness. For example, someone who likes chocolate, and some don't. Properties of chocolate does not change. Finally, if you have some momentum (say, change someone, or, conversely, to stop the endless partying), it is rarely possible to say in advance whether it makes sense for the momentum to implement.

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— So, it is difficult to say whether useful for this kind of monogamy or not?

Depends on living conditions. From the point of view of evolution "useful feature" means "giving the opportunity to leave behind more offspring, which will have time to breed". It is obvious that at some point in the past promiscuity ceased to lead to a lot of children and it became more profitable to be faithful to one person.

Unambiguous historical data are scarce, but if you look at the London of the XVIII century, it will become clear that the children of women who left promiscuous lovers, lived to maturity less than children exemplary men. Single mothers often were not able to feed all offspring and abandoned them.

So, under certain conditions, loyalty to one partner allows you to grow the maximum number of descendants. But it's not necessary to be strict monogamos. For example, male birds often help raise offspring to one female and if you get the chance to mate with another, but do not produce food for her children. And, of course, unbelievers can be not only males: people have known cases where twins (fraternal twins) had different fathers.

— There is a feeling that at least in Russia, women who have given birth to many children have lower levels of income and education.

Probably this was true not so long ago. A couple of centuries ago in the wealthy families had ten children.

— That is, the number of children in General is not related to intelligence and wealth?

— Definitely not been connected before. Most likely there was some connection between wealth and number of children surviving to maturity, but certainly you cannot claim that. Until recently, we have so often been struck by a variety of diseases that it is impossible to understand how income and education affect fertility: often died poor and rich children.

— For example, in Russia today launched a campaign against abortion, and in most cases unwanted children save the ones who are least able to raise them with dignity. Those who are smarter and richer, just not give birth. Whether it will lead to the fact that the population will become more stupid?

— Very slippery topic. Let's not forget that in the modern world, and some of these unwanted children will receive education, and wealth, which their parents had. Here affects not only genetics, but environment. And genetic differences between people are not so much. Although we love to focus on those fractions of a percent of DNA that distinguish us from each other, I think, from the point of view of some artificial intelligence we're all basically the same.

— Continuing the theme of differences: is there any sense for men to be "manly" and women "feminine", vary in size, wear different clothes?

— A feature of evolution is that it always gives information about the past and not the present. Certainly ahead of gender differences, masculinity and femininity have helped our species survive, but what value do they have now, hard to say. And this is true for any characteristic that is inherited: rather, he gave an evolutionary advantage, but this does not mean that it gives an advantage now.

But this does not mean that at this time, the sign is useless?

— Yes, of course. Well, culture plays a role, of course.

— By the way, it seems that almost every culture people tend to dislike "not such as all", and especially for those whose sexual behavior seems unconventional, homosexuals, asexuals. Why?

— Let's start with the fact that they dislike not everywhere. For example, in the far East(apparently, refers to Japan, and Russian far East. — Primas'. author) children often grow as transgender and in General nobody sees this as a problem — at least as far as I know. To be gay in new York and Mississippi is not one and the same. In the first case of homosexual I draw much less attention. So in this question the options are many.


We know too little about homosexuality. In other species it almost never occurs (so that it systematically, throughout life), we really do not know the mechanisms by which developing homosexuality


Overall, it seems to me (although I have no scientific evidence of this) that the ability to agree with the majority, conformity was at one time an important factor in human evolution. And no matter what to accept — sexual, culinary, or some more preferences. If you disagreed, you were banished from society, and therefore, you couldn't wait for any external help and were doomed to death.

But gay and asexual, if they follow the same strategies of sexual behavior, and so will not breed. In evolutionary terms, they're dead. Why oppress them further?

— Honestly, any thoughts on the matter. Personally, I don't understand, what does it matter to people to the sexual orientation of others. Most likely, earlier, when the social pressure was stronger, homosexuals often had children though have not experienced satisfaction from sex with a person of the opposite sex. Most likely, people who are not involved in reproduction, is a relatively young phenomenon.

And that "forced reproduction" of gays — one of the reasons why they are not getting smaller over time?

— Probably, Yes. To be honest, we know too little about homosexuality. In other species it almost never occurs (so that it systematically, throughout life), we really do not know the mechanisms by which homosexuality develops. Moreover, in different cultures people may be more or less bisexual. I apologize for some questions I can't give exact answers: I'm not sure that they are in principle known to someone.

And imagine: all species of animals have the opportunity to do something like in vitro fertilization (IVF). No need for courtship rituals, even sexual intercourse is not necessary. Do you think all the animals took advantage of this opportunity?

Depends on the animal and his sexual behavior. Surely some male spider would be happy to leave the envelope with sperm and run away, not to be eaten. On the other hand, if sex brings animal fun, it is unlikely it will be to abandon it.

One of the reasons for which the ECO is currently popular, especially among older women, is that it gives new life opportunities. I would venture to suggest that the popularity of IVF suggests that people have created a cultural situation that is different from the biological. Most other species live only on the biological laws, without a touch of culture and, therefore, it is unlikely that they badly need in vitro fertilization.

— True if the concept of "the selfish gene" for our species? Roughly speaking, it is important for us to spread his own genes?

Is an evolutionary concept, and if so, then it is true for all types — and hence for us too. Another thing is that again, the us is strongly influenced by culture, and it interferes with the course of evolution. The idea of the "selfish gene" suggests that genes within the same organism are competing with each other in an attempt to reproduce, transmitted to posterity, and the most important thing in evolution is the survival of genes, not the survival of the species.

Evolution, in fact, still lives or dies. Sometimes, evolution causes extinction: it favors characteristics that provide an advantage to a particular individual in the short term, but in the long run reduce the species adaptability.

I don't really like the concept of the selfish gene, because it creates the feeling of cooperation does not exist or if it does not play any role. However, the cooperation is. By the way, she also evolyutsioniruet.

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— I mean that IVF and other techniques to get rid of the complex of sexual behavior and mating, as for the "selfish genes".

It's too early to talk about how IVF will affect the evolution of a man: a little time from its introduction into practice was held, besides, the vast majority having children, so to speak, in the usual way.

At some point I pondered whether the use of cesarean delivery to the fact that women will lose the ability to give birth. But with the bulldogs already almost happened. I did some calculations and it turned out that for at least another few centuries people will not lose their ability to normal childbirth. And despite the fact that caesarean section has been used for a very long time.

— Summarize. Sexual human behavior and the evolution of this behavior are more dependent on culture than biology, and to study this behavior, we must first consider the cultural context.

— Absolutely correct. In addition, it is necessary to consider how the genes interact with the environment (with the same education), their influence should not be considered separately.

To help you in this genetics of behavior?

— Probably. There is only one problem which can't be circumvented. Researchers of sexual behavior people — the people themselves. This prevents an impartial look at the object of study.

For example, we are studying mouse. Our senses do not work as its something that she can hear and smell, we are not able to perceive. On the one hand, it is not very convenient, and with another — allows to avoid some too arbitrary interpretations.

Another example. A few years ago he published a book "A Natural History of Rape" ("Natural history of rape"). In it the authors examine the sexual behavior of different species of insects, and then carry it to the people. I believe it is ill-conceived and irresponsible, and for several reasons. For example, if the authors compared the sexual behavior of birds, not insects, with a human, they would have come to quite different conclusions.

We might be able to create machines and computer programs, able to impartially evaluate our sexual behavior?

— Cans. That's just to create them will also be people, and they will bring into the programme their views on themselves. And whether people will want to demonstrate their sexual behavior to the robot.

— Then there is no chance to achieve objectivity?

— Not exactly, no, but they are few. In principle, it is possible to design a behavioral experiment to the participants and the scientists themselves are objective. But it's not easy. A good example is the experience with sweaty t-shirts. As the name implies, female subjects had a sniff of some sweaty t-shirts of unknown men and say you like or dislike them smell each t-shirt.


Broken woman and the samurai healed Mother

Stephen Hawking: the Past is the probability

This experiment was to identify women's preferences, and thanks to two-way anonymity, he has revealed objectively. But again, not the fact that revealed preferences are satisfied in real life: we do not always get what you want. No life is not enough to cycle through all partners and to select among them the perfect one. I must admit that usually people form pairs with someone you will find. For other animals this, incidentally, is also true.published 


Author: Olivia Judson

Text: Svetlana Yastrebova


P. S. And remember, only by changing their consumption — together we change the world! ©



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