Monday, May 24, 2010

Re-Defining the E-Word

What does the word “evolution” mean?

In last week’s post on this blog, I argued (as have a number of others before me) that the “e-word” should be expanded beyond biological evolution to include no less than the “history of the universe.” In this more comprehensive sense, evolution is able to capture in a single word the unified story of the cosmos, life, and culture. In response to this post, one of the comments I received came from Kenneth (last name not included), who argued that evolution should be restricted to biological evolution. In his words,

"So much of the refusal to accept evolution (in this country at least, the US) comes from those who think evolution explains the origin of life. It, of course, does not and has nothing to do with abiogenesis. But presenting the origin of the cosmos as "the epic of evolution" is just going to further that divide. We need to teach about the Big Bang, stellar birth and refinement, how planets form, the Miller-Urey experiment's results, and evolution and natural selection. But we can't put them all in the same basket since they're not actually related (and saying that non-reproducing things "evolve" is adding gasoline to the fire, too).

Kenneth raises a critical issue, and I thank him sincerely for taking the time to articulate it. Because “evolution” has become such a loaded word in the United States (and a number of other countries), I have thought long and hard about whether or not to expand the word to refer to the history of the universe. After all, I reasoned, people might reject the Great Story out of hand, effectively tossing out the baby with the bathwater because of a bias against anything evolutionary. Eventually, however, I came to think that the two truly deserve--even need--to be linked. Not only is the teaching of biological evolution a critical endeavor worthy of our energies—so too is the teaching of the Great Story. And I’m convinced that this pair of ideas can be mutually reinforcing. I devote today’s post to a brief outline of my position.

Ultimately, of course, how we decide to define the word “evolution” is a matter of semantics, and words can have multiple meanings. For example, at Dictionary.com, the biological definition of evolution is, “change in the gene pool of a population from generation to generation by such processes as mutation, natural selection, and genetic drift.” However, nine other definitions are also listed, including one that applies to the history of the universe: “any process of formation or growth; development.” So the question is this: Do we elucidate or muddy our understanding of nature if we refer to the Great Story of everything as the “epic of evolution”?

Kenneth contends that the expanded version of the word gives ammunition to those who conflate the process of (biological) evolution with the origin of life, suggesting that evolution has nothing to do with life’s beginnings. I would disagree with at least the latter half of this claim. Recent work by origin of life researchers have revealed remarkable continuities between geochemistry and biochemistry, between the living and nonliving worlds (1). My strong hunch—likely bolstered by the announcement this week of the first synthetic life (2)— is that resolution of the origin of life problem, one of the greatest mysteries in science, will reveal blurry boundaries between the animate and inanimate, akin to what we see between major groups of biological ancestors and descendents (e.g., theropod dinosaurs and birds).

On a larger scale, I think that using evolution to describe the Great Story serves at least two important purposes. First, it underlines the fact that the evolution of life (and humans in particular) is not separate from the rest of nature. Rather, life’s origin and expansion is merely one of the latest examples of increasing complexity within a single, unified, and stunningly creative whole. By treating biological evolution as an entirely distinct process, we tend to construct a false dichotomy and ignore the many similarities between organic and inorganic transformations.

For example, although increasing diversification has been a major trend in both cosmic and biological evolution, another frequently overlooked propensity is toward unification. As I described in a previous post, “The numerous and dramatic increases in complexity, it turns out, have been achieved largely through a process of integration, with smaller wholes becoming parts of larger wholes. Again and again we see the progressive development of multi-part individuals from simpler forms. Thus, for example, atoms become integrated into molecules, molecules into cells, and cells into organisms. At each higher, emergent stage, older forms are enveloped and incorporated into newer forms, with the end result being a nested, multilevel hierarchy.” Indeed a strong argument can be made that the major steps in complexification over the past 14 billion years have been achieved large through unifying rather than diversifying (3).

A Darwinian sense of evolution has also helped to inform ideas about evolution in the nonliving realm. Perhaps the most surprising case in point is Lee Smolin’s cosmological natural selection theory (4,5). Smolin, a theoretical physicist, has suggested that the rules of biology apply on the scale of the cosmos. Specifically, the eventual collapse of a black hole may result in the creation of another universe on “the other side.” If so, each universe generates as many universes as it does black holes, the equivalent of reproduction. Due to a number of physical constraints, the majority of these universes may undergo “heat death” before they can generate stars and black holes; that is, they die off before reproducing. If so, there would be a kind of natural selection favoring the formation of universes of that could successfully spawn new universes!

The second important reason I advocate use of the e-word to describe the Great Story is that it increases the scope of the challenge facing those who oppose the notion of organic evolution. That is, opponents of evolution, especially young Earth creationists who argue that the universe is a mere 6,000 years old, must contend not only with the Everest of evidence supporting biological evolution, but also with the equally abundant evidence in favor of cosmological evolution (the origins of the universe, galaxy, solar system, etc.) and cultural evolution (e.g., evidence of tool use within the hominid lineage). Anti-evolutionists typically search for supposedly “fatal flaws” (e.g., structures showing “irreducible complexity”) that might indicate the work of a “Designer.” But there will always be things in science that cannot be fully explained (at least not yet), and overthrowing the notion of evolution requires that one upturn the entire mountain rather than a few grains of sand. Explicitly linking the evolution of life with the evolution of the non-living universe greatly increases the size of that mountain.

Finally, much of my confidence in promoting an expanded definition of evolution comes from such luminaries as biologist E. O. Wilson (6), who made this argument long before I did. I recently received additional assurance when I ran into my friend Eugenie Scott, Executive Director for the National Center for Science Education (NCSE; the leading organization promoting). Arguably more than anyone else in the country, Genie and the NCSE are on the frontlines fighting to keep the teaching of biological evolution in the science classroom (and creationism out). When I asked for her view on the matter, Genie responded in wholehearted agreement with me, adding that she too defines evolution as “the history of the universe.”

So let’s feel free to refer to our cosmic story as “the epic of evolution,” and then recognize biological evolution as a subset of this grand narrative (7). At present, the general public is effectively illiterate with regard to both, a dire situation that, as argued last week, deserves immediate and widespread attention.

References and Suggested Sources
1) To give just one example, check out a terrific talk by one of these workers, Eric Smith (http://fora.tv/2007/04/18/Inevitable_Life).

2) Wade, N. Researchers say the created a “Synthetic Cell.” New York Times, May 20, 2010. (http://www.nytimes.com/2010/05/21/science/21cell.html).

3) Margulis, L. 1998. Symbiotic Planet: A New Look at Evolution. Sciencewriters, Amherst.

4) Smolin, L. 1997. Life of the Cosmos. Oxford University Press, Oxford.

5) Lee Smolin Wikipedia entry: http://en.wikipedia.org/wiki/Lee_Smolin

6) Wilson, Edward O. 1978. On Human Nature. Cambridge, Mass.: Harvard Univ. Press. Pp. 206-207.
7) For additional reading on this topic, I recommend:
- Cosmic Evolution Wikipedia page: http://en.wikipedia.org/wiki/Cosmic_evolution

- Epic of Evolution website: http://epicofevolution.com/celebrate.html

- Chaisson, E. 2006. Epic of Evolution: Seven Ages of the Cosmos

Images
All images courtesy of National Geographic: http://photography.nationalgeographic.com/photography/

2 comments:

  1. For a long time, I categorized "biological evolution" and "abiogenesis" separately in my own mind, and taught them separately, too (really only mentioning the latter). However, when a similar subject arose awhile back over at Pharyngula, PZ Myers made a relatively simple statement that really made me rethink the whole subject: abiogenesis is simply the evolution of non-living chemicals to living chemicals. While this is dependent solely on the (probably arbitrary) definition of "life" us humans apply to the matter, the more I've thought about it, the more I think this is a perfectly appropriate viewpoint, and I no longer make the distinction between the two as separate, unrelated (or even distantly related) events -- it really is just a spectrum of events, not a dichotomy.

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