分节阅读 Table of contents

• 1.How does Evolution work？

  • This book is about evolution. All talks can start with the misfit bumblebee. Considering its size, shape, and wingspan, whose "design" seems unnatural to fly. Their wings look like decoration, no more useful than a store-bought bow glued to a gift. But it flies from flower to flower well enough. However, evolution can reveal its mystery perfectly.
    
    Generally speaking, the process of evolution can be divided into two steps, one is random mutation, and the other is natural selection.
    
    You must have been aware the random mutation: You and your parents cannot be exactly the same; a spotted cat is likely to give birth to black kitty; and the flu viruses in every winter are not the same, too—If didn't take latest vaccines you may be infected. These are all living examples of random mutation.  So how does the bumblebee become that they look like today?
    
    Before the famous evolutionist Darwin, there was a naturalist called Lamarck, who speculated that when animals and plants took efforts to exercise certain organs, so that the function of these organs could be enhanced, and then those features would pass on to their offspring. Thinking as Lamarck had thought, giraffes must get their long necks by reaching again and again. In the same way, it must because of 24/7 practices stout bumblebees can fly with their poor wings. His idea was so encouraging. We can conclude that one might become new species as Spiderman or Teenage Mutant Ninja Turtles by exercise.
    
    However, What Darwin later realized, and what Lamarck missed, is that complexity emerges slowly through a whole population, not quickly within a single person or animal. In other words, random mutation is actually very, very slow; the whole species goes through thousands or even many more generations to produce one few new features. Therefore, to grow into what it is today, bumblebees had gone through countless forks in their road of evolution, then became separated from its siblings.
    
    However, being cruel but necessary, the nature does not keep all the mutations. Only the individuals who survive until they produced offspring can pass its features on. In this sense, there were some other kinds of strange bees, but because they could not go through the natural selection, and thus, disappeared in the natural history. This is the better answer deduced by Darwin: evolution is actually driven by the idea of "the fittest survive".
    
    In addition, a crucial evolutionary requirement is this: At every stage, with every change the organism make, the whole thing has to still be functional. An example in point is Archaeopteryx, or the proto bird, the amazing fossilized animal that resembles a bird and land-crawling reptile at the same time, in other word, half-bird-half-dinosaur.
    
    Archaeopteryx, which has half a wing that seems even worse than bumblebee, in our modern evolutionary way of thinking, is a transitional animal. But at the time Archaeopteryx lived, it wasn't a transitional anything. It was a creature well adapted to its environment. The purpose of the feathers was either to fly or to keep warm, to make it sexually attractive, or perhaps to glide shortly. In any case, with this pair of wings, Archaeopteryx survived, and eventually evolved into today's birds. But if the wings hindered its survival, this feature would not be able to be preserved. This shows that Archaeopteryx was a winner of natural selection, similarly, so is bumblebee, and human.
    
    What happens to other species also happens to us. It is not difficult to find the fact that all of lives are direct consequences of evolution. On the other hand, evolution is not essentially different from other scientific discoveries that led to polio vaccines or smart phones. The theory of evolution takes us into the future and the past, and thus enables us to understand what we observe in nature. As people learn more about evolution, they will realize that we aren't such a big deal. Humans are just another species on this planet trying to pass our genes into the future, just like…bumblebees.

• 2.Become More Similar, Or More Dissimilar？

  • Evolution has wonderful effects that far more than "designing" a perfect bumblebee. The wonders of nature include two amazing trends：some organisms become more similar, while some other do the opposite. Technically, the rule of "the fittest survive" made two modes of evolution: convergence and divergence.
    
    Convergence means structures in living things develop into similar features as different organisms make their way through their environment generation to generation，such as birds and bats, or fish and whales. Fossil evidence indicates that the ancient whales looks more like crocodiles, which have legs that can walk. So why then they became like fish? Did tunas or salmons teach the whales any lessons? According our knowledge of fish culture so far, it seems impossible. Anyway, only the theory of evolution can explain this phenomenon logically. The real reason is that the basic conditions of their existence were similar, such as rules of gravity and the density of water, in other word, they must adapt to the same environment. Thus, different species may go in the same direction toward evolution. It's a universal rule of evolution's adaptive imperative: Fit in or die.
    
    Beside the convergence, we can also see the phenomenon of divergence.
    
    Check out our arm bones, if you often eat chicken wings, you will find incredible similarity between them. But how could it be? Evolution can explain it: Humans and birds share the same ancestors; their differences are gradually formed in long process of evolution. Though today chickens and humans rarely call each other brother or sister, many similar structures are retained. Anyhow, how different are birds and us! How did the nature do it?
    
    First, some contingency of natural events can facilitate changes in gene variant. Because of environment changes, populations diverge genetically as time goes on. And after natural upheaval, only a few survivors' gene can pass on, which leaves their offspring relatively monotonous in gene diversity, and therefore they will become more separated from offspring of other survivors. In this ways, species gradually differentiates. For example, a species of bird would be divided into two separated groups because of the splitting and drifting of continent plates. Those two groups of birds originally have some slight genetic differences. And as they no longer mate each other, the differences then become more and more obvious. In addition, because of the environmental changes, they have to adapt to the new land and thus gradually differentiate into two completely different species.
    
    Sex is another factor that makes organisms more diverse. Why does anybody have sex? You might be better at answering this question. But from an evolutionary point of view, sexual reproduction produces offspring with more complex mix of genes than asexual reproduction. It may provide more chances for genetic innovations, which might lead to a more successful successive generation. The new mix of genes might also weed out genetic errors, which makes healthier offspring.
    
    What's more, sexual selection is another fundamental process in evolution. The process of sexual selection is the competition between individuals of the species. Individuals are competing for power to win opportunities that enable them to reproduce. Broadly speaking, only the strongest individuals can have offspring, so that the species can maintain a strong vitality. So to say, the term "meaningless sex" actually doesn't make sense. Sex plays a very crucial role in evolution. Don't you think this kind of science is amazing and sexy?

• 3.Why people don't believe in the theory of evolution?

  • No exaggeration, evolution is one of the most powerful and important ideas ever developed in the history of science. It describes all of life on Earth and any system in which things compete with each other for resources. It's such an enormous process that spans across billions of year. And it's profoundly humbling.
    
    However, there are many people still defying the theory of evolution, who look for ways to isolate people and to indoctrinate them so thoroughly. It's difficult for them to accept the facts behind evolution that organisms is not created by a Divine Power, the world is dominated by cruel laws of natural selection, and humans are not essentially special.
    
    A major reason for the many resistance to the acceptance of evolution is that some believe that the existence of living things depends on a supernatural designer. They will ask, if not a god, who can create such a perfect, subtle, self-consistent biosphere? People are astonished by the perfection and diversity of organisms, and thus assert that there is a Divine Power creating the whole of nature in a top-down fashion. In fact, nature works the other way around.
    
    Here's an amazing example: Barn owls have a structure of winglets unexpectedly like what a Boeing plane has to improve energy efficiency. But the design of Boeing planes is the result of extensive researches on aerodynamic. With the IQ of Barn owls, how could they consciously grow such smart feathers in order to improve flight efficiency? Therefore it is natural to think that a force far beyond human intelligence made this small miracle. Actually, it is selection pressure of nature selection that works to promote the evolution, rather than any designer. Natural selection is a sieve that living things have to pass through successfully, or we never see them again. So barn owls experienced competition for survival of millions of years before they naturally develop this feature. Million times of tiny random mutations had happened, but only some with such feature ultimately survived. In this sense, organisms that alive today are all results of evolution. But it is hard for many people to accept this simple fact.
    
    Sometimes, even evolution itself can also be a reason why people don't believe in evolution.
    
    Evolution has given us the troubling nature of short lives. A relatively short life hinders us from easily understanding the whole picture. And what we feel is that the final result of evolution is inevitable death. The fear of death makes people blame evolution for this unsettling conflict between the way we wish the world would work and the cold truth. People are dissatisfied with the result of evolution, so They do not accept the theory of evolution. Life can be so ironic.
    
    In some scenarios, opponents accept microevolution, as in the way one strain of virus can evolve into another, since it happens every year at flu season. But they'll turn around and insist that humans have nothing in common with the other creatures here on Earth, because a higher power must have made humans different. They use the term microevolution for the part of evolution that they find theologically acceptable, and macroevolution for the part they don't like. The truth is that none of the micro ideas makes any sense except in the context of the macro, and vice versa.
    
    It is no denying the students educated by pious theological view of nature can be polite and nice, but reason would not matter at all. That is a very troubling prospect indeed. They are and they will be excluding themselves from our society. In fact, inherent in this rejection of evolution is the idea that your curiosity about the world is misplaced and your common sense is wrong. This attack on reason is an attack on all of us. Indeed, evolution is science, but it is also a process driven by the human spirit. Learning about our place in the great chain of life is anything but sad. Discoveries are joyous; perhaps there is nothing more exciting.

• 4.Evolution and You and Me

  • Specifically speaking, what evolution matters in our lives? You might already have aches, pains, eyeglasses, and dental fillings. But your generation is good enough to make it this far. This is another consequence of being shaped by natural selection. We are just the latest version that is good enough in competition with so many other organisms in our ecosystem. None of us would be here if we weren't genetically good enough. That's a rather encouraging thought.
    
    However, our successful survival owes many thanks to today's drugs and vaccines, which are possible because of evolutionary insights. Human can produce effective drugs only by understanding the evolution of viruses and germs. Furthermore, doctors are starting to look at evolution not only as something that affects human health from the outside, but from the inside as well. The ecosystem or microbes in our digestive tract coexists with us and thus affects our health. We can't grasp the mysteries of human health without completely understanding the evolution of them. So to speak, human’s health really depends on the evolutionary researches. It is a strategy; it is science, rather than luck. You are here because a large number of people worked together around the world and across centuries to understand how the natural world really works.
    
    Evolution doesn't only affect our bodies, but also our emotions, behavior and even thinking.
    
    Evolution prevents us from racism. In evolutionary terms and biological fact, we are all almost identical. We each share 99.9 percent of the same DNA. The surprising thing is that skin color does not mean what a great many of us think it does.
    
    Evolution has taught us altruism. Humans, vampire bats, even birds and dinosaurs display altruistic behaviors because evolution taught them kin selection through the process. The selfless help between relatives can help individuals and populations go further in evolution. And studies show that impulse is widespread. Apparently, altruism actually is not a moral or religious ideal, no matter what some people might tell you. It is an essential, biological part of who or what we are as a species.
    
    Evolution also promotes the development of human culture. Think about this: how many things we pursued are actually for showing power or attracting the opposite sex? Human spend a lot on that, if not all. These activities come at a cost in much time, effort, energy, and resources. If you’ve ever seen the sweating guys at the gym or beautiful ladies on extreme high heels, you will easily understand that. Similarly, People urge to acquire titles and material goods to let others know their value, and further win in evolution. Everything humans do contains more or less the motivation of evolution.
    
    Though we already know a lot about evolution, natural systems are just too complicated for people to predict the effects of many evolutionary issues.
    
    For example, genetic engineering and the cloning are highly controversial. Those technologies would side step the evolutionary mechanism in nature. We cannot predict every risks behind them. But even worse, humans are directly destroying biodiversity. People cannot be sure of what will happen to a species' native ecosystem if it loses that species. Biodiversity is a safety net that helps keep evolutionary process going. If human destroys any species, other organisms will take the place of those we kill. But if human destroys the ecosystems we depend upon, we may kill ourselves.
    
    At the end of the journey of this book, we can contemplate the evolutionary process as a whole. Human struggle for Life that drives evolution on this planet; perhaps in the future that the same struggle will expand to a cosmic scale. Keep going, and the ideas just keep getting wilder. If only we keep our minds open to new ideas, our faculties keen to significant pieces of truth, our youthful curiosities forever engaged. Where did we come from? Are we alone? Want to know, search on!

关于本书 About the book

In Undeniable: Evolution and the Science of Creation, Bill Nye, American scientist and educator, refutes common misconceptions about evolution by logical speculation and solid evidence. He lists the widespread facts of evolution in life, which shape modern humans and the nature in various fields. And he believes it is profoundly humbling. As society learns more about the epic of evolution, they will realize that we aren't such a big deal.

With infectious enthusiasm, Bill Nye shows that evolution is much more than a rebuttal to creationism; it is an essential way to understand how nature works-and to change the world. And reading this book might help you become the science geek you always wanted to be.

本书金句 Key insights

● Evolution is one of the most powerful and important ideas ever developed in the history of science. It describes all of life on Earth. It describes any system in which things compete with each other for resources.

● The great questions of evolution bring out the best in us: our boundless curiosity, and our boundless ability to explore. After all, evolution made us who we are.

● We are a result of evolution, and therefore so are our creations—both the not-so-good and very good. It's glorious.

● This kind of science is amazing and sexy.