Why is sex important and where did it come from? I'll let you know right off the bat, that I'm not going to be talking about the sexual act. What I want to talk about is what preceded it and what comes afterwards, in evolutionary terms.
Scientists tell us that the Earth is 4.6 billion years old. And life is 3.4 billion years old. But sexual reproduction originated about 600 million years ago . That means that life was around for three billion years before sex came along. Before sexual reproduction, life consisted of bacteria and single-celled algae, which both reproduce by splitting in two.
When a bacterium reproduces it makes an identical copy of itself and then it divides into two. So, for asexual reproduction all that is needed are the basic ingredients of life: air, water, nutrients, energy, and DNA. What's interesting is what you don't need. When a bacterium reproduces asexually it doesn't need to relate to other bacteria, and it doesn't need to take care of the copy of itself.
Bacteria don't mature and they don't die either -- they just keep on dividing. No wonder it took three billion years for sex to develop: eternal life, no commitments, and at the first sign of responsibility bacteria can always say: "I'm splittin’."
For the purposes of this talk I'm going to define sexual reproduction as the production of offspring from two parents. Going from one to two changes the whole world. All of a sudden sex makes reproduction very complicated because it doesn't just require the elements of life that I mentioned previously. Now we're talking about a relationship between two parents, and a relationship between parents and their offspring, and the maturation of the offspring so that it too can become a parent, and then the inevitability of death. That's right -- the price of being able to reproduce sexually is death because once you start to mature you can't stop.
But where did sex come from? Somehow bacteria started relating to each other. They started to communicate -- they exchanged genetic material. And when they did that they were able to change their own genetic makeup. That's why bacteria can develop immunity to antibiotics so quickly -- because they can transfer the genetic material that confers immunity amongst themselves.... Smart little critters....
OK, but that's not real sex, so where did sex come from? I believe that sex is inherent in all life, from the very beginning, even though it was not always manifest. But I can't explain it in scientific terms, so instead, let me tell you a story:
When the solar system was created, at first there was no life on Mother Earth. She has had a long-standing relationship with Father Sun -- there has always been an attraction between them. But at first nothing came of it. We know that for sexual reproduction to work the prospective parents need to be in just the right relationship. Mother Earth and Father Sun had maintained just the right distance from each other. If Mother Earth had been any closer she wouldn't have been able to protect their offspring from the heat of Father Sun's rays. And if she had been any further away she wouldn't have been able to capture enough of Father Sun's heat to keep their offspring warm.
But in sexual reproduction the relationship isn't everything. You also need to reach a certain level of maturity. And here is where Mother Earth had to take the initiative. We know that females mature faster than males and I propose that this is because women bear more of the responsibility for raising children so they need to be ready sooner. It was just so with Mother Earth and Father Sun.
You just have to look at the way Father Sun treats everyone else to realize why this is. You see, Father Sun shines his light on everyone without fail. He can't help it. For all the light that he radiates he has no way to discriminate, no way to choose who to shine on and who not to shine on. Talk about ironic -- his light may be the origin of consciousness but he himself is blind and couldn't care less.
On the other hand, Mother Earth grew and physically matured. From out of her body arose the oceans and the atmosphere and these interacted to form perhaps her most beautiful feature -- the ever-changing patterns of weather. For she never appears the same from one day to the next.
Just as sexual reproduction requires two adults, the creation of life required both Earth and Sun. For without the continued outpouring of Father Sun's energy life could not flourish. The Sun is a dependable but a harsh father because he shines on everyone without mercy. His rays of ultraviolet light would kill all life without the protective blanket of Mother Earth's atmosphere. And just as a blanket keeps us warm by keeping the heat from our bodies from escaping, Mother Earth's atmosphere holds Father Sun's heat even when she has turned her back on him, which she does every night.
Thus, out of the enduring relationship between Earth and Sun, life came forth to clothe and transform the Earth into a being unlike any that the universe has ever known before. So different from either parent, the living Earth creates its own chemical, physical, and biological environments in a single evolutionary process called the web of life.
To answer the question, "Why is sex important?",
I bring your attention to three vital factors whose evolutionary development was only made possible by sex and whose qualities help to define both our humanity and our unity with all life. These three are: biodiversity, consciousness, and love.
Sexual reproduction first occurred roughly at the boundary between the Pre-Cambrian and the Cambrian eras from 500 to 600 million years ago. Before sex we have three billion years, during which single-celled creatures replicated asexually. After sexual reproduction becomes possible there is an explosion in the variety of life forms: from single-celled, to multi-celled, fungi, plants, animals: crustaceans, echinoderms, fish, insects, amphibians, reptiles, birds, and mammals. All because when two parents reproduce sexually they create offspring that's different from either parent. This magical increase in genetic variety accelerates evolutionary change which, in turn, accelerates biodiversity.
It's obvious that asexual reproduction, which creates copies of the same creatures, (which is what happens in cloning) does not produce biodiversity except via mutations over fantastically vast spans of time. Sex changed all that, it made complex forms of life possible, it made human beings possible, and it made possible the wonderfully intricate interplay between the myriad of species which we call an ecosystem.
As we all know, there's logistics in sex, which we mostly take for granted but, when you think about it can be quite challenging. First you must be able to find and distinguish members of your own species. Then you must distinguish those of your own species who are members of the opposite sex from those who are of the same sex. Then you must choose a member of the opposite sex and communicate to them who you are such that they in turn can recognize you as a member of the opposite sex and make the appropriate choice.
Asexual creatures, on the other hand, don't have to go to all that trouble. They only need to recognize food or danger and they have no need to be recognized. But sex requires cooperation and communication and reciprocal recognition. These needs seem to point evolution in the direction of increasing powers of awareness and consciousness and to the development of love in humans and higher animals.
From the point of view of asexual reproducers these powers of consciousness, cooperation, communication, and love are unnecessary expenditures of energy. But the most wasteful of all is the goal of sexual reproduction, the production of offspring. Instead of simply making an identical copy of yourself you gotta nurture and take care of a baby. Pre-Cambrian critters must have been scandalized. Why make that kind of sacrifice when you could be immortal -- busy churning out copies of yourself forever and ever? A baby has half it's genetic material from somebody else. You're gonna grow old and die for that?
Whenever we see a baby we can't help but smile. We often feel joy. Sometimes a lot of joy. We can't help being interested in a baby, wanting to care for it. Babies grow up to be so different from either their mother or father. Maybe from the point of view of an asexual reproducer this is a scandal, but from the human point of view it's always a miracle.
Babies need to be protected, loved, and nurtured. Mothers do this naturally because they can't help loving their babies. Caring by it's very nature, spills over into caring for others and other kinds. We care about our children and our grandchildren and even about everyone else's children. We develop complex networks of cooperation between peoples who are not just our kin, to further the goals of caring. Indeed, we are here today because countless generations of people loved and cared for their children and families and fellow humans. Without sexual reproduction this would not be so.
We see a direction in evolutionary development which originates with sexual reproduction, such that sexual attraction which initially guides animals towards prospective mates leads to more enduring forms of love via the birth and nurturing of babies. We hardly ever see fish and amphibians caring for their young. Among reptiles, only alligators and crocodiles do this. But when we get to the higher animals such as birds we see them feeding their young and helping them to fly, and we see mammals caring for their young for extended periods of time. Only a handful of animals form enduring bonds of love: geese, who mate for life, elephants, killer whales, the great apes, and humans.
A mother bear will fiercely defend her cubs. She will stand her ground against bigger and more powerful males. But a father bear has no love for his cubs and will just as soon kill them as look at them. But something beautiful happens when humans arrive on the scene because not only does a mother love her child but a father does too. And unlike most other animals, children are capable of loving their parents even into their adulthood.
In humans affection and caring comes to transcend procreation as we develop deep relationships amongst family and friends. These relationships add to a web of social cooperation that makes up human societies. Our caring for others has come to transcend caring for ourselves and our offspring because our survival depends on cooperation with many others. But our consciousness is evolving even further as we come to realize that caring for our kind requires that we care about the entire web of life of which we are a part.
For, just as the evolution of sex was contained in the relationship between Earth and Sun, the evolution of consciousness is contained in the relationship between humankind and the entire web of life on Earth. The Sun shines on, indifferent to whether we live or die. But we are conscious. We can choose whether to create or destroy, whether to love or to hate. We have that power and that responsibility. Just as all life depends on the Earth and the Sun, our future depends on what we do with our consciousness.