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Human impact on evolution

rebeccafarber's picture

Becky Farber

February 16, 2007

Paper #1

            Throughout the course of class discussion and Ernst Mayr’s What Evolution Is, we have explored the notion of evolution occurring by a series of random events and interactions. “Different genotypes within a single population may respond differently to the same change of the environment. The changes of the environment, likewise, are unpredictable” (Mayr, 277). Humans by chance evolved to this latest stage with somewhat of an ability to recognize the very process by which we came to exist. On the one hand, advancements in technology, matched with the dominant attitude and position of the human race, allow for intentional and increasing changes to be made to the evolutionary path. Yet intrinsic in human nature is the faculty to adjust the direction of evolution, and this can be done without knowledge of either evolution or technology. I argue that humans alter the process of evolution both deliberately and unintentionally. Our role as the most developed organism allots us the supposed authority and innate ability to modify the course of evolution and the future of development, not just for our own species, but for others as well.

            Our adjustment to the evolutionary process is not a recent occurrence attributed solely to the advent of modern technology and advancement of thought; we have been changing it since the beginning of the time, including ancient humans’ shift of the climate. As it turns out, ancient humans were influencing the earth’s climate long before they could even understand it, by their release of greenhouse gases from manmade fires built to clear land for settlements and farming (PhysOrg, 2005). This begs the question: are we as humans destined to manipulate what is around us? As the most complex beings thus far in the line of evolution, are we innately ordained to change what becomes of this continuing process? My response is certainly yes. Lacking the understanding of evolution or the rise of technology, our position as the most advanced species granted us the unique opportunity to alter the course of life. It can be argued that these early humans who built fires were unintentionally changing humans’ future evolutionary response to the deterioration of the ozone layer. Even without realizing that this was the effect of their actions, humans at this time were impacting the environment in which they lived, creating a chain of events to follow that would shape evolutionary processes for years to come. Perhaps with the further depletion of the ozone layer, humans will evolve in the future to develop a layer of skin that protects against ultraviolet rays. As indicated by the ancient humans, evolution can be impacted by the actions of humans without them even realizing it.

            There is a fine line when it comes to human’s impact on the evolutionary process in terms of what is deliberate and what is not. For instance, the cultivation of flowers has proven to be largely dependent on human’s own love of the plant. A study by Rutgers University found that human affection impacted the survival of certain flowers, and that “as humans moved into agricultural settings…flowers would have been weeds… [They] might have been tolerated because of their beauty… Because they are a source of pleasure – a positive emotion inducer – we take care of them” (Britt, 2005). This is demonstrative that human desire – in this case, the wish to be surrounded by attractive plants – controls what is around us, including these species. We chose not to eradicate them – a power we do have as the dominant species – because they pleased us. Whether this is a conscious or subconscious decision made by humans to alter this organism’s own evolution is not completely clear. I fail to see this as an instance of humans deliberately impacting the sprouting of flowers; rather, it is a result of our inborn attraction to the plants. Thus, our position as the most superior enables us to alter the course of evolution of the flowers, even if we do so unknowingly.

There are indeed cases in which it is clear that humans are purposely altering the trajectory of evolution. Some say we have earned our right to manipulate evolution’s track through our better understanding of such a complicated progression. We do this through processes such as stem cell manipulation.

“Human stem cells are unique cells that can transform into all the parts needed to create a living being. There are different types of stem cells. Brain stem cells in a human fetus, for example, morph into the neurons and all other cells needed to make a mind” (Britt, 2005).


However, it is also clear that being the most superior[1] species has given humans the authority to use the resources of the earth in ways not constructive to the rest of the species. "All the life processes of this planet will be where they belong – where the gods meant them to be – in our hands. And we’ll manipulate them the way a programmer manipulates a computer” (Quinn, 1992). Yet the future of evolution does not guarantee our own existence or our dominance. We as humans assume that our position as the most developed and the most superior is a permanent fact, when evolution itself is a continually changing process.

          I claim that evolution is this alterable process due to both the advent of technology and the built-in nature of humans as the most advanced organism. With many possibilities for positive evolutionary change – some as simple as fields of more flowers – there is also room for evolution to take a frightful turn, with humans trying to evolve to protect ourselves from the environmental dangers we ourselves have created. Even still, the fact remains that humans are capable of manipulating evolution whether they choose to do so or not. Our position as the most dominant species is a double-edged sword. It is the reason we understand evolution, and it is our understanding of the process that can afford us the ability to change any negative course. Yet being the last in the line of a series of increasingly complex species also grants us an unmerited arrogance that may eventually conquer the rest of the species from which we once evolved.


Works Cited

Mayr, Ernst. What Evolution Is. New York: Basic Books, 2001.


Quinn, Daniel. Ishmael. New York: Bantam, 1995.


Britt, Robert Roy. “Stem cell research with monkeys sparks debate.” Updated

14 July 2005. <>.

Cited 15 February 2007.


PhysOrg. “Study: Ancient humans ‘altered’ climate.” Updated 9 September 2005.

            <>. Cited 15 February 2007.


Britt, Robert Roy. “Human Affection Altered Evolution of Flowers.”

Updated 26 May 2005.


Cited 15 February 2007.


[1] Superior is defined in this context as the most advanced species in an evolutionary line. As the most culturally developed, socially capable, and technologically adept species, the human race is more superior by these terms than any other organism.


Anne Dalke's picture

staking a claim



I need a title: as a quick shorthand to your paper’s main idea/argument. You are very clear, though, before the first paragraph ends, in staking your claim: “I argue that humans alter the process of evolution both deliberately and unintentionally.” And you return to it @ the end: “I claim that evolution is this alterable process….”

What is much less clear to me is why you feel the need to make that argument. Who are you arguing against? What point of view are you correcting? Who assumes that our position is a “permanent fact”? I’m not arguing with your claim; I think it is correct. I’m not sure, though, why it needs to be made. Who thinks that we are not participating in the process of evolution, and why do they need to understand this differently? A claim, to be a claim, needs to be “out there” a bit, a little edgy. You’re not close to the edge….

I have a similar question about your insistence on the distinction between “deliberate” and the “unintentional” changes that humans bring about. What difference does intention make? If we cause some effect (positive or negative) what does it matter that we wanted (or didn’t want) to bring about that event? That we were “knowing” or “unknowing”? (I’m thinking of the common phrase, “I didn’t mean to hurt you….”)

You’ll see that I also took note of your repeated use of phrases like “dominant,” “most developed,” “most advanced,” “most superior,” “destined,” “ordained” to describe the human position in evolutionary development. Paul’s section had an interesting discussion last week in which they played with the idea that bacteria were actually “more advanced” than mammals are—because such a huge variety of life forms can evolve from bacteria. This is not the case for elephants! (i.e.: they can not serve as a source, as bacteria have been the source, of a multiplicity of life).

P.S. Get hold of the book The Botany of Desire—it really goes to town with your notion of human desire as causing plant evolution!