Story of Evolution, Evolution of Stories
Bryn Mawr College, Spring 2004
First Web Paper
On Serendip

Has the narrative of Mayr and his fellow naturalists—those evolutionists who include natural selection in their explanations and who comprise a strong majority of evolutionist voices today—now entered a sort of evolutionary stasis? Not yet.

For example, consider Mayr's central theory of speciation as it applies to a creative species such as humans. There are cultural and creative aspects of our so-called "higher level" species that have the potential to perturb whether and how new species taxa might evolve from homo sapiens: mobility and its effect on isolation, technology applied to environmental and physiological conditions, artificial constraints on reproduction, social cultures, and our creative abilities. Whether our species is better equipped to survive or more likely to accelerate towards extinction may, in part, be determined by these factors and their interactions.

Evolution is. Therefore, we are. The human species is an infinitesimally improbable out-come of countless, unrepeatable iterations of a process that itself is a fluke. To paraphrase the late naturalist Stephen J. Gould, erase the tape, have one player move a few feet to the left for good measure, do a retake, do a trillion trillion retakes, and nothing akin to homo sapiens is likely to emerge. Evolution is not intuitive, nor would any sane gambler bet on its odds. There are no "proofs," no conclusions based upon experimentation and testing. What we know about evolution derives from historical narrative—the evolutionary biologists' reconstruction of what might have happened. Their scenario has also evolved through iterations of accumulating, adapting, and eliminating ideas according to new findings, new observations, and new knowledge. In the process, the narrative's woof and warp have tightened. Gaps narrowed to the point that, in "What Evolution Is," biologist Ernst Mayr could proclaim, "Evolution is not merely an idea, a theory, or a concept, but is the name of a process in nature, the occurrence of which can be documented by mountains of evidence that nobody has been able to refute...It is now actually misleading to refer to evolution as a theory, considering the massive evidence that has been discovered over the last 140 years documenting its existence. Evolution is no longer a theory, it is simply a fact" [Mayr 275].

Central to this "simple fact" is the concept of speciation, which was developed in the 1930s by Dobzhansky and Mayr. According to them, allopatric speciation is contingent upon the spatial and temporal integrity of a population, a species taxon. That population must be isolated from others of its species, either by some geographical barrier or by the establishment of a founder population beyond the reach of its parent. Members of the taxon interbreed freely but in isolation. Over time, selection for phenotype occurs. Some phenotypes are eliminated while others prevail based upon how well they can adapt to changing conditions (selection pressures) in their surroundings. Individuals (and their genes) who cannot adapt are eliminated. If too many indi-viduals succumb, that species will become extinct. Variation and elimination under large-scale pressures can also lead to the creation of new space, new niches that a population may exploit through adaptation—a better chance to thrive. Generational turns of a species do not result in improvement in any directional sense, only in change that is useful for the species to survive or exploit the latest shift in conditions. However, evolution of a species does involve cumulative adaptations, and the number of attributes that can combine to adapt increases with each turn. No sweeping strategies are in play, just short-term, reactive, tactical maneuvers.

But what happens when a species is not isolated, does not allow its members to breed freely, has the wherewithal to re-engineer its surroundings and even itself, is inclined to react and make decisions based upon the beliefs, attitudes, and behaviors established by social groups, and transcends other species in its ability to communicate, imagine, and create? How do these attributes affect speciation, which is central to evolution, which is central to our continuance? Or is it?

Mobility and its affect on isolation: Whether allopatric speciation is dichopatric (geography separates two or more taxa) or peripatric (a smaller founder population becomes isolated), speciation depends upon reproductive isolation. Among members of the humans species there is no such condition. Invention has led to mobility, and humans can now reach everywhere on the planet. Our taxon is our species and we have inadvertently denied ourselves the option of morphing to adapt. Perhaps we could artificially isolate populations, but that is not sociologically feasible. While proximity is a dominant factor in who reproduces with whom, none of us is geographically removed from the opportunity to reproduce with any of the others. At some point, the process of speciation among humans could be compromised by this factor.

Technology applied to environmental and physiological conditions: From bioengineering the body to artificially remediating an ecosystem, material nature no longer exists independent of overt, directed human intervention. Humans are exceedingly clever beings. We can eliminate an increasing number and complexity of selection pressures as they arise in our environment and in our bodies—without the traditional operators of reproduction, inheritance, and elimination. We can prolong, improve, and create life unnaturally. We may even learn how to prolong cellular life indefinitely—and make death a process of elective or artificial selection. Our applied intelligence had already precipitated the rapid, simultaneous extinction of species coexisting in a geographical region, e.g., the rainforests of the Amazon River. According to paleontologist Neil Eldredge who, along with Stephen Gould, developed the idea of stasis and its affect on speciation, "most adaptive evolutionary change occurs in conjunction with speciation...Natural selection shapes most evolutionary adaptive changes nearly simultaneously in genetically independent lineages as speciation is triggered by extinction in "turnover" events...such turnover events have causal roots that are deeply ecological and arise, at base, from large-scale changes in the physical envi-ronment..." Humans manufacture large-scale change. To what degree are our technological "ad-vancements" affecting our own speciation and even the ability for us to evolve via this process?

Artificial constraints on reproduction: So far, evolutionary change depends upon heritable variation. For a vast majority of humans, society, religion, and/or law governs mating. In many societies, close relatives are not permitted to reproduce, thereby removing the powerful genetic effects of inbreeding from the process and biasing the gene pool. Each human has two copies of any given gene (two alleles at each locus)—one from each parent. If the parents are related, the alleles have a higher probability of being identical. Therefore, inbreeding tends to amplify both beneficial and detrimental traits. At what point is speciation—which depends upon random inbreeding and out-crossing—compromised by cultural constraints regarding sex and marriage? If variability is damped because of regulation that takes place within human genomes, then the lack of in-breeding might skew inheritance even more dramatically.

Social culture: In the article "The Objects of Selection," Ernst Mayr wrote: "There is, how-ever, also a second kind of selection... better referred to as "selection for reproductive success." It includes such phenomena as parent-offspring conflict, sibling rivalry, unequal parental investment, unequal rates of division of prokaryotes, and many of the phenomena studied by sociobiology. In all cases, genuine selection is involved, unlike survival selection. Considering how many new kinds of selection for reproductive success are discovered year after year, I am beginning to wonder whether it is not even more important than survival selection, at least in certain higher organisms." Mayr's conclusion is not trivial. The two phenomena of biological evolution and cultural evolution co-evolve us. If sociologically driven selection criteria that are to some degree under our control can have more influence over our evolution, then what is the relative future impact of speciation?

Creativity: Our evolution and the process of evoltion may be co-dependent, even recursive. According to neuro-biologist William H. Calvin, "We have achieved an extraordinary ability to pretend, fantasize, lie, deceive, contrast alternatives, and simulate. Our minds can operate on the unreal, and the formation of unreal, blended spaces says a lot about our creativity." Add to that that humans can communicate with words, teach each other (and other species), and learn in social groups. These creativity factors separate our species from all others. Manifested as cultural variation and in the creation and exchange of knowledge, what effect do these traits have on human speciation and the future impact of the evolutionary process?

All of these modern human characteristics—mobility, technology, sexual selection, culture, creativity—appear to have the potential to significantly impact speciation opportunities for our species. On the other hand, if all species begin with speciation followed by stasis and at some point thereafter, abrupt descent to extinction, perhaps we are creating our own advantage.
Evolution is. Therefore, we are, but will we go on because of evolution's protocols ac-cording to Darwin and Mayr or in spite of them? Just as Napoleon took the crown from the hands of the Pope and crowned himself emperor—and with the risk that our sense of control and prowess may be equally delusional—as we evolve, we are taking evolution into our own hands.

Works Cited
Calvin, William H. "Why Create a Brain?" 2003. http://williamcalvin.com/2003/Why%20a%20creative%20brain.htm
Eldredge, Neil. "Species, Speciation and the Environment." 2000. ActionBioscience.org. http://www.actionbioscience.org/evolution/eldredge.html
Mayr, Ernst. What Evolution Is. New York. Basic Books. 2001.
Mayr, Ernst. "The Objects of Selection." 1997. Proceedings of the National Academy of Sciences of the United States of America. March 18; 94 (6): 2091–2094. http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=33654


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