-Josh Weisberg (superswimmer51@sbcglobal.net)
Friday, March 23, 2012
Evidence: Fruit Flies vs. Humans
In the evidence section, footnote 9-10, Shenk writes that "if humans were fruit flies, with a new generation appearing every eleven days, we might be tempted to chalk it up to genetics and rapid evolution" (174). In comparing fruit flies with humans, think about Shenk's claim that talent is a process (10), made up of different environmental effects influencing our genes and gene expression. So if fruit flies have such short generation span, their process is based on adaptation and evolution. Compare these short life span adaptations with the process humans go through over their lifetime, averaging between 70 and 80 years. Which process develops more? Obviously, the human's is not an adaptation, and will not carry over to the next generation, but still, which process is more efficient and successful? Connect back to the biological theme of evolution and natural selection, and compare the two organisms as well as the two processes in general.
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While a human is very efficient at changing non-physical attributes to gain success, I believe that the long process of evolution is ultimately better at producing more fit organisms. As Shenk further notes in the Evidence section, studies have shown that a "single fly's random genetic mutation can spread into a whole community in a matter of months" (174). Humans' inability to adapt, in one generation, to its environment is a greater deterrent than the long process of evolution.
ReplyDeleteThis represents a Darwinian vs. Lamarck argument, which questioned if an organism can actually adapt to be more competitive just by trying hard enough. Humans can obviously try to gain physical advantages (such as height, musculature, etc.) but it ultimately fails to produce results, much like Lamarck's theory with giraffes and its supposed ability grow a longer neck if necessary (in one generation). He proposed that "life took on its current form through natural processes," but was later disproved. Just as humans can try to adopt Lamarck's theory, in the end, evolution proves to be the more efficient, albeit slower, process.
http://evolution.berkeley.edu/evolibrary/article/history_09
Nathan Ro (nathanro94@gmail.com)
Humans and fruit flies are obviously very different species and therefore also evolve in very different ways. Humans, having a life span much longer than fruit flies, have more exposure to environmental conditioning. Fruit flies simply experience the uncontrollable process of natural selection; the flies with the most advantageous genes live longer to reproduce and spread their genome. Obviously, with humans, we are given the advantage of time and intelligence. A child that is born to parents that are not particularly intelligent always has the option to improve or, as David Shenk states on page 10, “we are better at stuff because we’ve figured out how to become better”. We are not the slaves of our ancestors, limited to only their scope.
ReplyDeleteNathan Ro, in the previous comment made the statement that “Humans' inability to adapt, in one generation, to its environment is a greater deterrent than the long process of evolution”. I do not believe this statement is accurate because humans have the ability to recognize talent, and therefore have more control over their evolution. Acclaimed anthropologist and sociobiologist Sarah Blaffer stated in an interview with Radio National that “talent evolved long before even language, the holy grail of humanity, and that we became emotionally modern before we became anatomically and behaviourally modern”. Her statement suggests that humans have been able to label and recognize an advantage for a long time. This opens us up to a path of conscious evolution. It is not an outside source of natural selection determining whether we live to pass on our genes or not. Instead, we can recognize that if a person has superior medical knowledge, we should keep them alive, even if they have a condition that would make them die naturally. Therefore, by making the choice to let a doctor survive, even though they may be crippled, we increase our own chances of survival.
In this way, we are not limited to an outside source of evolution and we can always overcome our failures and turn them into our strengths. As human potential is so great, a flaw that relates to simply one weakness will not lead to death. A fruit fly that has a weak heart will die due to this flaw because it is weakened in its ability to find food, fend off predators and pursue mates. Yet, a human with a weak heart can still become a brilliant mathematician and evolve that way. It is because humans have so many different ways to survive in this society that we have so many diverse traits. Therefore, the human process of evolution is much more efficient than a fruit fly because we have time to develop our talent, and fruit flies do not have the means to overcome their deficiencies.
(Liz Gorelick lizgorelick@yahoo.com)
Although an organism may have a long lifespan and produce less offspring over its course, this is not a detriment to its evolution at all. Organisms that have longer lifespans are often much more complex, and this longer lifespan is an adaptation to develop their unique traits.
ReplyDeleteAs Liz said, humans are able to utilize conscious decisions in order to advance their species. Because of the myriad avenues of success that humans have, physical handicaps are no longer a death sentence, especially as our society has developed.
However, these conscious decisions are not the only route of adaptation that humans have – in organisms that may not necessarily experience many mutations in the genome due to few generations, changes in the epigenome can more than make up for this.
Fruit flies may experience more changes in their genome because of the many generations, but humans experience many more changes in the epigenome because of their long life span and subsequent influences from the changing environment. This makes longer lived organisms just as evolutionarily virile as fruit flies.
Environmental changes influence histone acetylation and DNA methylation, which both change how tightly DNA is packed together in the nucleus. This in turn controls whether transcription is able to occur, and controls the final expression of that gene (Campbell 358).
Just like genomic factors, epigenomic factors can be inherited. This recent discovery has huge implications for biology, and according to Shenk, this is “perhaps the most important discovery in the science of heredity since the gene”. Epigenetic inheritance allows long lived organisms such as humans to pass on the many changes they accumulate in their lifespan, making them evolutionarily competitive with shorter lived organisms such as fruit flies.
Even though Shenk says that “A single fly’s random genetic mutation can spread into a whole community in a matter of months,” humans can theoretically achieve the same with environmental influences on the epigenome. Changes in human culture spread like wildfire, and these changes definitely have an impact on the epigenome, and through epigenetic inheritance, subsequent generations. Epigenetic changes can happen in many individuals at once, and have the potential to allow an organism to respond to changes in the environment without needing to change the genome at all (http://learn.genetics.utah.edu/content/epigenetics/inheritance/).
All of these factors prove that humans and fruit flies do not necessarily have an advantage over the other’s system of adaptation and evolution, but in fact use different mechanisms.
David Whisler (dwhis428@gmail.com).