On pages 63-64, Dr. Moalem
discusses different adaptations that have arisen in different areas of the
world. For example, in Africa, people usually do not have dense body hair, but
around the Mediterranean basin, body hair is much more dense. Explain how this
connects to big idea 1: the process of evolution drives the diversity and unity
of life. If possible, reference your evolution chart from the beginning to
explain how this distinction occurs.
Dr.
Moalem also describes the ancestry of Dr. Henry Louis Gates, a distinguished
African American scholar on the Harvard board of African and African American
Studies, to illustrate the genetic intermixing occurring around the world. How
can half his ancestors be white but he doesn’t show any traits that make
intermixing of traits obvious? How does this genetic blending connect to big
idea 1?
By Daniel Majeed dmajeed4@students.d125.org
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ReplyDeleteBody hair developed as a selective advantage to people in areas around the Mediterranean Basin because of the prevalence of mosquitos and consequently malaria. Dense body hair prevents mosquitos from biting and individuals with it can survive and reproduce due to the selective advantage which connects to Big Idea 1: the process of evolution drives the diversity and unity of life.
ReplyDeleteIn the book, Dr. Henry Louis Gates is shown as an example of how diverse the world is today. The book says, "...some genetic testing revealed that Dr. Gates had no relationship to the slave owner-but fully 50 percent of his genetic heritage was European. Half of his ancestors were white." This show that traits don't necessarily show the diverseness of a family tree. Traits, like those of African American and Dr. Gates, were selected for based on his families environment to the point where European traits were not expressed. The African American traits throughout time provided a selective advantage for Gates' ancestors and thus they were able to survive and reproduce and thus passing down their African American traits. This connects to Big Idea 1 and how the process of evolution drives the diversity and unity of life.
Skin color specifically involves genetics and how some genes can be expressed over others and thus dominance. Skin color is determined by melanin production. In particular, the are 2 genes for skin color that have a dominant and respective expression or phenotype. Therefore, there are 16 different basic combinations possible for skin color alone. However, in the case of Dr. Gates, he might have randomly inherited both dominant alleles for skin color and thus expressed darker skin color. Random fertilization and the process of meiosis ensure that babies are born with a blending of genes. Also, the dominant alleles throughout many generations would have slowly tarted to phase out the frequency of the recessive allele.
http://www.biology-online.org/3/1_genetic_control.htm
http://biology.clc.uc.edu/courses/bio104/meiosis.htm
Andrew Arceo - ibanezrg120ftw