Beginning on page 13, Moalem provides an explanation of where hemochromatosis may have originated, and how it eventually became beneficial to the people who had it. This relates to Big Idea 1: The process of evolution drives the diversity and unity of life. The idea is that over time, because of environmental pressures, a population can change its "genetic makeup" because there are genetic variation within the population itself.
When it originated, how did hemochromatosis (which is now considered a disease), actually help the vikings survive and reproduce? During the plague, how were people of hemochromatosis able to survive and reproduce? Or...in other words, how did natural selection allow a specific genetic mutation that started in an individual to thrive and spread throughout a large population?
Starting with hemochromatosis in his book, Moalem gives several examples of mutations that are hurtful to us right now. Why, then, is this book called Survival of the Sickest, when these disorders clearly do not help us at all?
There are also other genetic disorders that might be similar to the examples mentioned in this book. Similar in the way that they are still with us because they must have had some evolutionary benefit to us sometime in the past. As Moalem said, if the disorders were really 100% hurtful, they would have been weeded out by natural selection.We also have body parts and reactions that do not benefit us at all - they might sometimes even be considered harmful. These disorders and body parts/reactions might include: ADHD, cystic fibrosis, schizophrenia, wisdom teeth, the appendix, and goosebumps. (Please) choose one to google and see how it could have been beneficial to us in the past.
I am just wondering...but, in your opinion, do you think that someday humans will be born without wisdom teeth, or even without appendixes? Or are the selective pressures they exert not strong enough, dooming them to be vestigial structures forever?
(Thanks for reading. My name is Hugo Lee and my email is hlee3@students.d125.org)
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ReplyDeleteWhile looking up information on wisdom teeth I found reasons in which wisdom teeth benefited humans in the past. The lack of contemporary utilization of wisdom teeth relates to Big Idea 3: Living systems store retrieve, transmit and respond to information essential to life processes. Because human jaws have become smaller throughout evolutionary history, when wisdom teeth form they often become impacted, or blocked, by the other teeth around them. Also, if the tooth partially erupts, food can get trapped in the gum tissue surrounding it, which can lead to bacteria growth and, possibly, a serious infection. So the question that is presented is why we keep these vestigial organs.
ReplyDeleteThis can be seen as humans were able to use their wisdom teeth in order to accommodate the rough food that were a part of early diet's. The human body has stored this information in order to maintain the ability to chew rougher foods. As explained by an Rachele Cooper "biologists now classify wisdom teeth as vestigial organs... [as] the modern diet has softer foods." (http://scienceline.org/2007/02/ask-cooper-wisdomteeth/).With the change in environmental pressures the need for wisdom teeth has not only disappeared but also have produced new problems.
Addressing the fact that vesitigial organs currently have no true function the organs should disappear. Also according to Campbell there was always a previous function for the vestigial organ stating that vestigial organs are " remanants of features that served important functions in the organism's ancestors"(463). This is based on the fact that the organs do not present a selective advantage for humans and requires energy in order to make and maintain. If similar selective pressures were to arise again humans could expect to see the same or evolved forms of the organ again.
(Jimmy Wang, jimmypelewang@gmail.com)