Human Evolution - Supporting Evidence

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Human Evolution - Supporting Evidence

While there is no evidence that supports the idea that humans are now evolving completely in adaptation to a man-made environment instead of a natural ecological environment, there are some scientists that claim that humans have moved into an entirely new era called the Anthropocene Era and are living in an environment that has been primarily shaped by people.

The Anthropocene Era

  • In 2000, atmospheric chemist Paul Crutzen announced that he believed man was no longer living in the Holocene Era, but instead, society had moved into a new era, one that was "shaped primarily by people."
  • Crutzen stated that "from their trawlers scraping the floors of the seas to their dams impounding sediment by the gigatonne, from their stripping of forests to their irrigation of farms, from their mile-deep mines to their melting of glaciers, humans were bringing about an age of planetary change."
  • He and his colleague, Eugene Stoermer, began calling this age the Anthropocene Era, or literally, "the recent age of man."
  • According to Rubert Hunziker, "75% of Earth's surface has been modified by the human footprint."
  • Christian Schwägerl, a German biologist, stated, "We are witnessing the transition from blind evolution according to Darwin’s laws, to a conscious evolution directed by the human mind."

A Paradigm Shift

  • The move into an era that would "make human activity central to its conception of the world, rather than a distraction" would signal a major paradigm shift.
  • Man has been peripheral to evolution for centuries: Scientists realized that Earth wasn't the center of the universe and Charles Darwin "fitted humans onto a single twig of the evolving tree of life."
  • According to Simon Lewis, an ecologist at the University of Leeds, embracing the Anthropocene Era "means treating humans not as insignificant observers of the natural world but as central to its workings, elemental in their force."

Fossils as a Record of Time

  • In the past, fossils have been the primary way scientists distinguish periods of ecological time, and in the future, when scientists examine the fossils of today, they will clearly see that humans were present.
  • However, those who claim that this is a new era believe that "the fossil record of the Anthropocene will thus show a planetary ecosystem homogenized through domestication" and that " humans are not just spreading over the planet, but are changing the way it works."

Evidence of Man Changing the Earth's Systems

  • In the past 200 years, man has released quantities of fossil fuels that were built up over hundreds of millions of years. This release has "given them a commanding role in the planet's carbon cycle."
  • Even though the natural flow of carbon dioxide into and out of the atmosphere still greatly outweighs what humans are putting in every year, the "human addition matters disproportionately because it unbalances those natural flows." It results in putting more carbon dioxide in the atmosphere than can be removed naturally.
  • Human intervention in the nitrogen cycle has "increased the annual amount of nitrogen fixed on land by more than 150%," and unlike other systems that have been affected by humans, the "remaking of the nitrogen cycle was deliberate."
  • The wingspan of cliff swallows in the United States has become shorter over the past twenty years based on the kinetic force of cars. Cliff swallows began using highway bridges as breeding grounds, but often, the birds were hit and killed by cars because their large wings did not allow them to move out of the way fast enough. In the next two decades, "the numbers of short-winged swallows increased, as it was easier for these birds to quickly swerve than for those with longer wings."

Man-Made Evolution Possibilities

  • Since many humans rely on devices to do most of their work, some scientists believe that "the changes in behavioral patterns and adaptations that are caused by these technological advances could prove to be the primary driving forces behind the next stage of evolution for [the] species."
  • Natural selection is dying out because of technology that allows man to eradicate disease and manufacture reproduction.
  • The ability to quickly adapt to new technology may be an evolutionary adaptation that could result in natural selection where "even a person with a slight physical disadvantage but with robust mental capabilities can flourish in this world."
  • It is possible that the human brain will evolve to rely more on the ability to analyze information rather than retain it because computers perform this function for humans.
  • Another possibility is that human hands and feet may undergo evolutionary changes to be more efficient since they are mostly no longer needed for arduous tasks like hunting and building shelter.
  • Evolutionary changes to humans' chests to make them stronger and have natural airbags could allow humans to better withstand car accidents.
  • Transhumanism can make "a person smarter, stronger and energetic" and has been seen in genetic engineering and in the development of bionic body parts.
  • Artificial evolution is also "not too far off in the future, and soon people might be able to select the different characteristics of their offspring like mental capabilities, physique, and energy levels."

Evidence Against Humans Evolving Completely to Adapt to a Man-Made Environment

  • Survivors of infectious diseases pass on genetic resistance to their offspring.
  • DNA selection for resistance to deadly diseases like Lassa fever and malaria is still ongoing in areas where these diseases are common.
  • Genetic mutations in Tibet that allow locals to survive at higher altitudes are considered the "fastest evolutionary change in humans, occurring over the last 3,000 years."
  • The ability of some humans to product lactase is an adaptation that has allowed 80% of north-west Europeans to digest milk after weaning.

Research Strategy

In attempting to find supporting arguments, studies, and/or evidence validating that humans are now evolving completely in adaptation to a man-made environment instead of a natural ecological environment, we began by looking for official studies by using academic databases such as NCBI, JSTOR, and PEERJ, among others. We found many articles related to evolution, but they mostly discussed the theory of evolution, experiential evolution, and evolutionary genetics. There was no information on humans evolving completely to adapt to a man-made world. Our strategy shifted to articles published in scientific publications such as LiveScience, Nature.com, ScienceDaily, and more. Again, we found significant information in how humans have evolved until now and speculation on whether robots can be programmed to mimic evolution, but there was no evidence available on humans completely evolving based on a man-made world. We did, however, come across mention of the Anthropocene Era, which seemed to hint at how humans have changed the world to thrust society into a new era. We felt this might be as close as we could get to humans evolving for a man-made world, but we made one last attempt to find actual quotes or statistics that support this theory.

Our third strategy was to identify prominent evolutionary biologists such as Robert W. Allard, Richard Harrison, James Shapiro, Lynn Helena Caporale, and others to see if any had been quoted on the idea that humans are now evolving completely in adaptation to a man-made world. While many of these scientists question Charles Darwin's theory of evolution at least in part, none of them mentioned that humans are evolving to adapt in a man-made world. However, we did find more information on atmospheric chemist Paul Crutzen who put forth the idea of the Anthropocene Era. In absence of information on whether humans are now evolving completely to adapt to a man-made world, we provided information on how human activity has moved society into a new, man-made era.
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