Charles Darwin’s 1859 publication, On the Origin of Species, changed the way we look at biology forever. Its central idea, evolution by means of natural selection, explains how all life evolves. No single idea has ever explained so much. It stands apart from most, if not all, scientific discoveries in its outreach and simplicity. As with most great ideas, once grasped, one is inclined to ask: “Why didn’t anyone think of this before?”
Actually, others had similar ideas before Darwin, including fellow naturalist Alfred Russel Wallace. Wallace had figured out that species evolve through natural selection and sent Darwin his version prior to Darwin’s landmark publication. In 1858 they jointly presented their work to the Linnean Society of London. But ultimately, it was Darwin’s detailed explanation in 1859 that history would recognize.
Organisms evolve over time by means of natural selection. Each generation is tested by its environment; the traits that aid an organism to survive and reproduce will tend to be passed on to the next generation. Not necessarily all the time, but often enough or in greater numbers. Traits that are not useful will tend to be discarded when the organism that bears them fails to survive or reproduce.
Through this process survivors are copied with slight random variations, which are then tested many times over. In other words, survivors live longer and usually reproduce more, keeping their survival traits alive in the ensuing generations. Darwin wasn’t the first to suggest that organisms evolve from previous forms, but he provided the mechanism (natural selection).
Why is This Idea so Special?
- Outreach: Natural selection provides an explanation for how all of life evolves. It accounts for microorganisms, plants, fish, insects, birds, animals and of course humans.
- Simplicity: As oppose to other notable scientific ideas it can easily be understood by the general public. One does not need any technical science background to grasp the basics of this simple, yet elaborate idea.
- A confidence boost for science: Before Darwin, few could have predicted that all life on earth could be explained by natural means. Ever since Darwin, few should doubt the power of science to explain just about everything else.
- Philosophical implications: Darwin compelled us to take a second look at our place in the world. Long-held beliefs that humans held a privileged position, separate from the other creatures, had to be re-evaluated.
Darwin delayed the publication of his theory of evolution for about 17 years, because he feared a public backlash. And he was right in assuming that controversy would follow. His chief concern, I can only speculate, was probably religious. Natural selection can easily be viewed as taking god out of the creation business. If nature is shaping all of life, what is god left to do? Despite some criticism, his book drew worldwide interest. Even today evolution still gets some people upset. Why is such a profound idea so difficult for some? Let’s look at possible reasons why:
- Religious : Evolution contradicts the bible’s account of creation; however, many people seem to have no problem squaring evolution with the bible. They either don’t really know what the bible says or they don’t take it literally. Whereas literal interpreters of the bible clearly see what evolution means for their faith. For them evolution is akin to a fatal blow.
- Supernatural thinking: If one is inclined to believe that there exists a dimension outside the laws of nature, then anything is possible. Life can then be guided by a supernatural force. If that is the case, evolution is no longer required as an explanation.
- Evolution is confused with natural selection: I suspect that some people think of evolution as simply gradual change over time. In terms of the cause, they can use their imagination. However, the key insight is the means by which change happens. Evolution is the process and natural selection is the mechanism.
- Deep time: There is nothing in everyday experience that can prepare us for the time scales involved in evolution. Simple life emerged on earth (in the ocean to be exact) 3.8 billion years ago. And from there spread to all regions of the planet. That’s 38 million centuries for life to evolve to eventually create you and me. Given enough time, minor variations in each generation can result in changes that may be hard for some to grasp.
- Sometimes the truth hurts: There is no plan in evolution, no final destination that has to be achieved. Furthermore, human beings don’t hold any privileged position in the tree of life. Darwin described life as a family tree, with different species spreading in all directions. Life could no longer be seen as analogues to a ladder, with humans occupying the top rung.
An Inspiring View of Evolution:
Evolution has been contested by some segments of the general population unlike any other scientific idea. I believe that the main reason for this is that evolution is measured against an ideal (the belief that we are the focus and the ultimate goal of life). Some people simply don’t like the implications of evolution. However, if you contemplate what had to happen for you to be reading this post, everything changes.
The evolution of life on earth is a 3.8 billion year story in which all of these things (and much more) happened:
- Simple life began in the ocean.
- Single cell life developed into complex life.
- Life crossed over to land.
- Life diversified so it would not fail.
- The planet remained stable enough to support life.
- There needed to be sufficient time for life to continue to evolve.
Our moment in the sun is made possible due to a lengthy series of events that didn’t need to happen, yet they did. We are part of a special breed; we are the survivors of natural selection. If we think of evolution this way, it can take the sting away from some of its harsh realities. Perhaps even a feeling of gratitude can arise in us when evolution comes to mind. In closing I will give the last word to evolutionary biologist Steven Gay Gould when he wrote in, Ever Since Darwin: “Shall we appreciate any less the beauty of nature because its harmony is unplanned?”
References: Stephen Jay Gould, Ever Since Darwin (New York: W.W. Norton & Company, Inc., 1992), 27.