It is a shame that books like Jerry A. Conye’s best-selling book Why Evolution is True (2009) is necessary for the twenty-first century. After all, Charles Darwin wrote his groundbreaking work On the Origin of Species by Means of Natural Selection was published in 1859. Since its publication many other scientific discoveries have been made to support Darwin’s dangerous idea. Evolution should not be a controversial issue and sadly it remains so even in the most educated countries of the world. Part of the controversy could be because many people who oppose evolution have no idea what evolution is. Even I learned that I misunderstood parts of evolutionary theory and I have been fortunate enough to be taught evolution even as a child of deeply religious parents. However, I learned that evolution was “ just a theory.” I was not taught about what the word “ theory” actually means. Now after reading Conye’s book (which is shorter than Darwin’s and a lot clearer) I can agree with Carl Sagan when he famously declared in his PBS series Cosmos, “ Evolution is not a theory. It’s a fact.”
Conye dives into the meaning of theory right away in his introduction to Why Evolution is True. The meaning of theory has degenerated in popular culture to mean “ guess.” The real meaning is to make a statement based on evidence. This is part of the whole meaning of the scientific method: ask a question, form a hypothesis, test it out and revise the hypothesis as results from experiments come to light. Conye notes that no one seriously questions the germ theory of disease – and that germs cause diseases is a theory. However, it is a theory supported by evidence. If someone wanted to, he or she could test this evidence and find it true for himself or herself. Evolution is a theory that has passed many tests since 1859.
Conye organized his book so that the strongest evidence for evolution and how it has passed test after test is presented in the earlier chapters. However, before he presents evidence, Conye wants to insure that the reader knows exactly what he is talking about. He does not take for granted that everyone reading his book will be familiar with the theory of evolution. He spells is out. It was here in the first chapter that I realized that I had a major misunderstanding about the theory of evolution. I had thought evolution was a process where more advanced life forms were directly descended from simpler life forms. I thought, for example, that chimpanzees were the direct ancestors of humans. I thought wrong. Evolution states that all life forms share a common ancestor. So humans did not directly descend from chimpanzees, but both chimpanzees and humans shared a common ancestor. Humans diverged from other primates but they both come from the same sources.
The second chapter is “ Written in the Rocks” which showcases the strongest fossil evidence for evolution. Conye not only showcases transitions fossils like Archaeopteryx but also compares these fossils to modern species that shared a common ancestor with now-extinct species. Conye also describes how fossils are formed and why they are so hard to find. A very particular set of circumstances needs to occur in order for a corpse to become a fossil. A corpse needs to die in or very near a body of water so that the corpse does not completely dissolve or become obliterated. It is surprising that so many fossils have survived to the present day. One objection creationists have about fossil evidence is that all fossils are supposed to be from the Great Flood (also known as the Great Deluge.) However, most species found are sea or water-living creatures. If a great flood had covered the earth, then surely most of the creatures that died would be land creatures. Creationism fails this test of the fossil record.
Chapter three is “ Remnants: Vestiges, Embryos and Bad Design.” This looks at comparative anatomy and embryology. Proponents of intelligent design state that all species were created as they are without any gradual changes in between. Intelligent design does not adequately explain why human embryos go through an “ evolution” of sorts in the womb. Why should human embryos have gills, for example? Why should they grow a coat of hair and then shed it before they are born? Evolution answers these questions. Modern species came from already existing species and gradually over time changed to fit whatever niche they find themselves in. A designer would not bother with useless organs such as eyes for moles or wings for the ground-dwelling kiwi birds. However, moles have tiny remnants or vestiges of eyes and kiwis have tiny stubs where most other birds have proper wings.
Chapter four is “ The Geography of Life.” Evolution only makes sense when there is a long enough time for species to evolve. Creationists usually insist that the earth is only a few thousand years old. If that was true, then there was not enough time for complex life forms to evolve on earth. So what does the geology tell us? How old are those rocks surrounding fossils, anyway? And even more puzzling, why are there species that are similar in South America and Africa? Conye explains how the continents move and continue to move. This information was not available to Darwin, although he was a dedicated student of geography. Conye also points out why many island species are so prone to extinction. It’s because these species have evolved for life on their own island and nowhere else. They also have not adapted for the sudden introduction of predators. Conye points out that flightless island birds like the kiwi and the kakapo cannot escape from cats brought to the island by sailors.
Chapter five is “ The Engine of Evolution.” This engine is adaptation to the environment and to all of the other species in the environment. The deadly dance between predator and prey helps drive evolution. For example, the alligator is basically the same body pattern that it was millions of years ago. It did not need to change much because its body did its job very well to find food and protection in the water and to come on land only on seldom occasions. Species like beach mice in Florida mutate to a different color to match the color of the sand where they live in.
Another engine that drives evolution is the mutation of genes. What I did not know before I read this book was that genes cannot copy themselves perfectly all of the time. When they make mistakes in copying genes, this causes a mutation. As Conye points out “ mutations occur regardless of whether they would be useful to the individual” (118). Previously, I thought that mutations happened because of very dramatic circumstances like exposure to radiation. Evolution makes sense in the light that mutations occur all of the time and not just during dramatic circumstances. If the mutation helps leave more offspring, then that mutation becomes more and more dominant and thus the creature evolves.
Chapter six is “ How Sex Drives Evolution.” It is essential that changed genes get passed down to the next generation if a mutation is to be successful and helps the life form better get food and withstand dangers. Mutations can also help creatures better secure mates. Conye describes how female peacocks chose their mates – by how splendid the male’s tails are. There ae many more instances of the spectacularly bizarre ways creatures make themselves conform to the sexual fashion of their species. Since evolution does not have a designer, it stands to reason that some adaptations to attract mates would wind up causing a species extinction. Conye gives the Irish elk as an example. Females only mated with males with the most impressive antlers. These antlers wound up weighting ninety pounds. They wound up killing more males than making males survive to breed.
Another misconception many opponents have to evolution also oppose abortion and fetal stem cell research. Some states are debating the “ personhood” of human egg cells. If these people would take the time to learn basic biology, they would stop thinking that egg cells are alive. All egg cells will ever be are egg cells. They will never spontaneously burst into the form of a baby. Unless they meet sperm, they never change. It takes both sperm and egg in order to generate the required chromosomes and genes to make a human baby. One thing I learned from Why Evolution is True is that many people prefer to be stupid rather than informed. Like the X-files used to say – the truth is out there. However, when it comes to evolution, especially human evolution, not many people want to recognize it.
Chapter seven is “ The Origin of Species.” Here Conye takes a page to make a bow to the person who wrote the books that triggered his interest in science, Ernst Mayr. Conye gets back to the point by noting that Mayr discovered that local “ primitive” peoples could distinguish almost as many separate species as trained biologists. Conye then describes what makes up a species – even when members of a species look very different from one another, such as with people. A species can produce offspring with other members of its own species. Conye even describes species as “ evolutionary accidents” (176). He then gives hybrids as an example.
This got me to thinking about mules. If evolution were not true, then mules would be an impossibility. Creationists say that species have always been as they were since the beginning of life on earth. Mules are the (usually) infertile offspring between a horse (equus caballus) and a donkey (Equus asinus). Because horses and donkeys can produce offspring, their split from their common ancestor must be relatively recently. I wonder how long it will take before horse and donkey matings stop producing mules.
Conye winds up this chapter with evidence for evolution nearly as strong as fossils, embryos and vestigial body parts – different species appearing during a person’s lifetime. Unlike in Darwin’s day, we can check the DNA of an individual in order to compare them in order to make sure that they are the same species. One can also trace the history of a species development by looking at the genes. Conye gives as example polyploidy speciation. Polyploidy creatures have far more chromosomes than expected. One rat species, for example, has 112 chromosomes. In contrast, people have 46. What happened here? Somewhere in the polyploidy species’ past, a hybrid appeared. These hybrids were able to reproduce. They could have been crosses between two species, but not always.
Chapter eight is “ What About Us?” which centers on the evolution of humans and the history of how we came to understand the evolution of humans. In Darwin’s day, there were no fossils that seemed to share features of both apes and humans. They have been discovered. The first were discovered in 1924, a relatively short time after Darwin died in 1882. Darwin had predicted such species existed and there they were. Later on came the infamous “ Lucy” (Australopithecus afarensis) discovered in 1974. Again, Darwin had predicted these “ missing links” existed and here is the proof.
Conye highlights the tradition of teaching that humans were somehow the only species that did not evolve. I know of people who have no problem with the theory of evolution – except when it applies to people. The objection is then that humans are not as special as all other species. People who oppose evolution often do so because of religious reasons. The big three monotheisms – Christianity, Judaism and Islam – teach that man was made in the image of God. They also teach that people possess immortal souls. So does this mean that God really looks like Australopithecus afarensis or that perhaps the so-called lesser animals have souls? These are important questions to some religious people. However, they are not scientific questions. There is no proof that souls exist, for example. Unless proof of souls can be found to exist in Homo sapiens, how can other species be tested for the existence of souls? This shows how hard it is to teach science because sometimes the answers do not fit in with our comfortable worldview. Because souls cannot be tested some people may wrongly conclude that science should not have anything to say about spiritual matters. However, it does. It says that so far no proof exists in many aspects of spiritual matters.
Conye also talks about a problem that today would make many Americans gasp. For the last century or so, biologists tried to find out if some races of humans were “ more evolved” than others. He does note that not only are there outward physical differences between races but some genetic differences. Conye notes that although differences between races do exists, for the most part these races are “ trivial” (214). He also points out that knowing one’s race helps a person know their risks for certain health problems. Human races are more proof for evolution. Mutations appeared to help humans adapt to whatever environment they live in for many generations. Races are still all humans since they can produce fertile offspring.
Another misconception that I had is that at some point evolution stops. It does not stop. Genes may lie dormant or it may be millennia before noticeable changes are seen, but evolution never stops. There is no ultimate final point to evolution. Creationists and proponents of intelligent design usually look at humans as the highest possible life form ever – except for God. One celled creatures did not live primarily to provide a step towards the evolution of humanity. They lived in order to eat and pass on their genes.
Religious groups are often reluctant to accept any type of change in how we understand the world, even when there is incontrovertible evidence. For example, look at poor old Galileo, prosecuted by the Church for his astounding astronomical discoveries. There had been a tradition in Christianity to teach that the heavens were perfectly made and did not change. Although the Catholic Church has now admitted that Galileo was right, many religious people oppose to change their ideas when it comes to evolution, animal rights or climate change. Many people who don’t believe in evolution also do not believe in climate change. They often do so for religious reasons. Religion seems to provide good answers to questions like “ Why are we here?” or “ What happens to us when we die?” Anything that could even hint that religious answers are wrong tends to get the cold shoulder from the religious.
However, belief is useless when it comes to practical matters. Evolution and climate change will go on whether you believe in it or not. This is something that I have to keep reminding myself because I keep forgetting it.
Perhaps there was an evolutionary advantage to beliefs such as a belief in God. Certainly when Christianity was made the official religion of the Roman Empire, you stood a better chance being a Christian than being a pagan. These beliefs (or the appearance of possessing these beliefs) would have crucial for survival then. They do not help us now when it comes to teaching science or dealing with climate change. Although there may be always people who refuse to change their minds, those who do may not wind up surviving to reproduce, especially if climate change continues to be ignored.
Earlier in the book, Conye trots out the old Creationist argument against evolution about “ what use is half a wing” (39). This is a variation on the old “ of what use is half an eye” question asked in Darwin’s time. People had problems wondering how missing links could possibly survive. For example, if birds came from reptiles, then how could a creature with half a wing survive? They do quite well as gliding or being able to out maneuver predators. So, what use is half an eye? Ask a blind person. Half an eye could be quite useful in helping to negotiate their environment. The evolution of the human eye was not to go into preliminary steps in order to wind up making a human eye. The eyes we have are far from perfect. They are easily injured. Many cannot see well without aids like glasses. We cannot see colors like infra-red. We also see in an extremely inefficient way. Light comes into our eyes and makes images that are upside down. Our brains have to tell us the images are really right side up. This shows that the human eye evolved not spontaneously or in any way following a design. It wound up in its crazy, inefficient way because it had millions of years of previous types of eyes to work with. Perhaps in a million years, humans will see infra-red easily and not need glasses.
Chapter nine, the final chapter, is “ Evolution Redux.” It acts as the book’s conclusion. Conye repeats about what he exactly means by “ evolution is true.” He means that the core concept of evolution is true. Scientists may argue about details about evolution, such as how long it takes for a species to change, but they do agree that species appear through slow changes over time. They did not suddenly pop up from the ground. They came about because of the previous material they had to work with – already existing species.
Conye also notes that evolution is not another form of predestination. All of our actions are not preprogrammed by our genes. There are still lots left to learn about how individuals differ from the rest of their species. Evolution or Darwinism does not give us all the answers for all time, but it gives us a good framework from which to pursue our further inquiries. That is one of the reasons why people may distrust science – because good scientists change their minds and their hypothesis when fresh, testable facts come in. Many people do not like that. They want an answer and they want it now and it better be the same answer for the rest of time. However, that’s not how science works. If a scientist is proved wrong, then that scientist must admit it and move on. It is the job of other good scientists to try to poke holes in the hypothesis of other scientists. Even Stephen Hawking has been wrong on occasion and he has admitted it. How many people would ever voluntarily admit that their views are wrong? This is one obstacle to universal acceptance of Darwinism. Who wants to own up to being wrong?
In the Introduction, Conye notes that evolution “ has been called the greatest idea that anyone ever had” (xvi). When I first read that, I thought Conye was over exaggerating Darwin’s dangerous idea somewhat. However, now that I have finished Why Evolution is True I am very close to fully agreeing with Conye. Darwin not only stuck his neck out by publishing the first well-structured theory of evolution but did it before much evidence for evolution was discovered. He lived before many transitional fossils were found, before even DNA and the decoding of species genomes had been discovered. He lived before it was discovered how continents move on tectonic plates. Perhaps even more amazing is that Darwin’s theory of evolution by means of natural selection is comprehensible to a very unscientific person like myself.
Many people – including myself – have the mistaken notion that science is only comprehensible to the select few. It is not. With teachers like Conye, theories crucial to modern science like evolution can be understood by the average person. There is nothing dehumanizing about learning science. It can open up whole new areas of wonder and awe that has traditionally been left to spirituality. I like knowing why I may need glasses or develop back problems – it’s because I am a creature with genes that used what material it had in order to make me.
Our writers will create one from scratch for
Coyne, Jerry A. Why evolution is true. Penguin, 2009.