Science is Sexy: What is Evolution?


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By Jimmy Rogers (@me)
Contributing Writer, [GAS]

A Slow Progression...

Few things in science cause as much public confusion as the Theory of Evolution.  While a number of great resources have already effectively elucidated the concept, including a video I’ve embedded in this article, I think it is valuable to repeat and expand upon these resources in a public fashion, lest The Theory fall out of common knowledge.

It is a credit to evolution’s founder, Charles Darwin, that he was correct about so many of the basic tenants in his original publication, The Origin of Species.  These principles can be generally summarized into four statements:

  • Variation, which arises through mutation, exists within and between populations for every trait.
  • More individuals are born into a population than can survive (usually because of the scarcity of resources).
  • Traits are passed down from parents to their offspring.
  • Individuals most fit to survive in their environment generally do (Natural Selection).

Something many people fail to realize about evolution is that the entire theory pretty much boils down into the aforementioned points.  Much of the controversy that has been held up by various anti-evolution groups centers around points not affecting the theory at all.  In fact, if the concepts of evolution were suddenly found to be false, our understanding of the nature of species would be a very poor one.  Let’s attempt to identify just what evolution DOES specify and leave be the things not covered by the theory.

moleculesFirst of all, it is helpful to think about individuals of a certain species as free-floating molecules.  In fact, this is pretty much how microbiologists have to view microorganisms, proteins, and other microscopic components of the biological world.  Imagine that these individuals are constantly moving about and encountering food, predators, good environments, and bad environments.  If you zoomed in on any one individual and followed its life, it would represent one possible jagged line.  That individual would also have a specific set of qualities or traits that are the results of its parentage.

Now, zoom out and look at all the individuals in the population.  They all have their own jagged lines that make up their physical movement and interactions as well as their own unique sets of traits.  Many of the individuals will be similar to one another and many may have similar “lives,” but when added all together there is an enormous amount of chaos going on in a single population of any sufficient size.  This is NOT evolution, but instead the conditions required for the evolutionary process to occur.

From these conditions it is very easy to visualize the process of natural selection.  Individuals essentially need to survive long enough to reproduce.  Reproduction might only require mitotic division (as in microbes) or mating might need to occur (as in animals).  In any event these are the first constraints.  Then individuals face dangers from predators and dangerous situations (a fish trapped in a draining tide pool or a stag falling off a cliff).  Lastly, individuals will compete with themselves and with other species for scarce resources such as food, water, and possibly space (a major concern of plants).  The competition resulting from these conditions rapidly selects a smaller group of individuals who will create the next generation.

Charles DarwinThis process can be termed “natural selection” because conditions chaotically (not randomly), “select for” or “select against” a given individual.  Note that nowhere in here is “survival of the fittest” a stated fact.  Often the fittest do survive because their traits make it more likely, but if a chasm opens up in the earth and only a few individuals survive, then it becomes “survival of the lucky.”  However it works, those who survive pass their traits on for another round and the cycle continues.

It is easy to see that over time, perhaps one year or thousands of years, that a such a chaotic population will not become uniform, but will collectively shift toward certain traits.  If the shift is dramatic enough, new species emerge.  Essentially a species is a group of individuals that are related enough to mate.  When a population branches (which can happen for several reason), two groups can diverge and eventually lose the ability to mate.  This is the basis for all speciation.

Regardless of what you have heard, this is really ALL there is to evolution.  I have not spent much time refuting the claims of those who oppose evolution (despite the enormous amount of evidence in its favor), but the following video does an admirable job, so I will let it:

Why is evolution so important?  Well, if you use evolution as a viewpoint and a tool when examining the world, some things fall into place and others don’t.  When things make sense with evolution, it’s a good chance that we can figure out an organism’s history (especially with the rise of genomics).  When things DON’T fit, then we need to reexamine the evidence and look for better solutions.  Sometimes knowing the missing pieces of a puzzle are important if we are to understand the bigger picture.

Before we finish, I would like to give myself a tiny bit of credibility as a science writer.  As of Saturday, I now hold a B.S. in Biology (conc. in Microbiology) from George Mason University.  While my experience in the field is still limited, much of the theory is still fresh in my head and easy to put down in writing.  Hopefully graduate school at the University of Maryland will help bolster that knowledge.  Then I can pass it on to you, the reader.

Feel free to leave a comment or a question (I try to answer any reasonable ones) or hit me up on Twitter!

[Evolution of Man image from The Daily Gazette | Molecules image from Nature's Right Remedies | Darwin Seated image is Public Domain]





23 Responses to Science is Sexy: What is Evolution?

  1. It should be observed, however, that the end result of natural selection is not survival, but extinction. Better than 99% of all species that ever existed became extinct because their adaptation to their niche was in such good correspondence that they did not survive change over geological time. Perfect adaptation is not a desireable characteristic on a dynamic world.

    • A very good point Mark!

      This process is actually the way in which recombinant bacterial strains are created. Microbiologists introduce a gene segment that is only taken up by a fraction of the millions of bacteria in a culture. The gene segment includes a gene for resistance to an antibiotic and the desired target gene (like creating insulin). The antibiotic is introduced to the culture and all but the small group with the recombinant DNA are destroyed. This is of course artificial selection, but the effect is the same.

    • "Perfect adaption is not a desireable characteristic on a dynamic world."?

      Yes it is, isn't it?
      One can not foresee the future, therefore adaption in order to survive is better than not survive in hoping that an unforseeable event in the near future (because in the far future I will be extinct) will change/kill my biological niche so that I (species) can survive and the other species, which adapted die.
      Nevertheless, every species has a heterogenity in its expression profiles that allows for great diversity even if their genome is identical (biological noise).
      Another point is that species is just a definition made by humans. Success can be seen from different viewpoints, life still exist, and species that have become extinct can be, in a broader view just like a single cell with an "unfit mutation" in a large culture or a step to another kind of cell even farther away (in a genetic sense).
      Even so, extinction is another definition made by us scientist, which is questionable. Have those "extinct" species developed into some other species, were they a "dead end"? We don't know. We can only guess, even phylogenetic trees are only guesswork, biologic evolution can go in more directions than what we think was/is "forward".
      Sry for the wall of text.
      Just wanted to say there is not such a thing as "desirable characteristics" in evolution.

      Please excuse my poor english. thx.

  2. It should be observed, however, that the end result of natural selection is not survival, but extinction. Better than 99% of all species that ever existed became extinct because their adaptation to their niche was in such good correspondence that they did not survive change over geological time. Perfect adaptation is not a desireable characteristic on a dynamic world.

    • A very good point Mark!

      This process is actually the way in which recombinant bacterial strains are created. Microbiologists introduce a gene segment that is only taken up by a fraction of the millions of bacteria in a culture. The gene segment includes a gene for resistance to an antibiotic and the desired target gene (like creating insulin). The antibiotic is introduced to the culture and all but the small group with the recombinant DNA are destroyed. This is of course artificial selection, but the effect is the same.

  3. George Mason! Who hooooooo! Best school I ever flunked out of!

    Thanks for a great article that really simplifies the whole messy thing.

  4. George Mason! Who hooooooo! Best school I ever flunked out of!
    Thanks for a great article that really simplifies the whole messy thing.

  5. The problem with evolution is this, virtually every mutation that occurs on a molecular level is maladaptive. The changes that are described(not really evolution but 'natural selection') occur under very different circumstances.

  6. The problem with evolution is this, virtually every mutation that occurs on a molecular level is maladaptive. The changes that are described(not really evolution but ‘natural selection’) occur under very different circumstances.

  7. That first part is true: most mutations are maladaptive. However, the useful changes don't really happen under different circumstances. There are many types of mutations, like specific point mutations (changes in a single amino acid), to larger changes where entire sections of a chromosome are moved or exchanged. Some changes add information (a changing or new DNA codon), some take away information (deletion of a gene or reduction in it's expression) and some simply change what is already there (moving genes), but regardless these are all forms of CHANGE in an organism (and it's offspring, it is has any). True, most semi-random change is bad (I say semi because nothing is truly random – the laws of physics and chemistry and biology play a huge role in mutations and other changes), but these bad changes are weeded out very quickly. Which leaves only the neutral or useful changes. Granted, these neutral or positive changes may not be vey common… but when thousands or millions of individuals in a species exists for hundreds, thousands, or even more years, these "uncommon" changes are not really that rare, and the positive effects they might have are quickly amplified by natural selection.

  8. Charles Darwin was actually not the "founder" of evolution. He was the founder of the idea of natural selection, which is the mechanism by which evolution occurs.

  9. Difficulty This is progress, almost all mutations occur at the molecular level is inadequate. Describe the changes that are not really changing, but "natural selection" takes place under very different status.

  10. Sorry, but you did not describe evolution, just natural selection. Those who disagree with evolution will agree with natural selection and have since before Darwin. Nothing new here.
    Thanks for what you did post though.

  11. As usual this pro-evolution article does not describe evolution. Evolution means and organism over time becomes another. For instance a fish becomes a reptile. Also natural selection cannot be the mechanism for evolution. That is because as you select for a group the selection is always smaller not bigger as the theory requires. Darwin gets an 1 from me at maths.