Shenk references in footnote 150 the work of Sir Roger
Bannister in defense of “high-altitude training and mild year-round climate are
critical” (302). Bannister argues that it would take drastic amounts of time
for lower elevated people to adapt to best exercise than those at a higher
altitude. Support for this would be found in the Jamaican and Kenyan athletes
that come from relatively high altitudes. However, this does not account for
the lack of athletes from the cities and towns that are drastically higher
elevated than their relatives Kenya and Jamaica. Most of these cities are South
American (e.g. Potosí, Bolivia and Quito, Ecuador), as well; therefore, this eliminates most economic differences (South
American countries, Kenya and Jamaica have relatively poor economic standing).
Therefore, do genes play a more drastic role in determining the athleticism of
the Kenyans and Jamaicans? Use your knowledge of genetics and gene expression
to help answer this question.
This comment has been removed by the author.
ReplyDeleteAltitude does play an important factor in the development of excellent cardiovascular fitness, which is vital for a runner. This is why the U.S. Olympic training center is in Colorado Springs, because the high altitude is excellent for training athletes. The lower levels of O2 at higher altitudes stimulate the creation of the hormone erythropoietin, which stimulates the production of more erythrocytes (Campbell 914). More erythrocytes allow the athletes to transport more oxygen throughout their blood, allowing their muscles to work even harder. Therefore, the high altitude environment does have a significant positive impact on the running abilities of Kenyans and Jamaicans.
ReplyDeleteAnother factor that has greatly improves the running abilities of Jamaicans and Kenyans is as David Shenk puts it "a particularly strong cultural 'achievement orientation'" (Shenk 105). This environment fosters Jamaican and Kenyan children to have a competitive spirit that will "strive to outdo others"(Shenk 150). Being raised in a culture that glorifies strong runners increases the motivation of the individual athlete to achieve greatness as a runner, and when many of those individuals exist in one culture, an especially strong few of them will go on to become world - renowned runners do to that culture of competition. According to the Institute of Biomedical and Life Sciences of the University of Glasgow and the Department of Exercise and Sports Science of Kenyatta University, the majority of Kenyan international athletes come from the same province and the same ethnic background, speak the same language, and ran to school each day. In fact, almost half of the international runners even came from the same Kenyan sub-tribe. Thus, the social environment also has a strong impact on the athletic prowess of Kenyans and Jamaicans.
With so many factors influencing Jamaican and Kenyan runners, genetics actually has relatively little to do with their success. Because only about 20% of a cell's genes are expressed at once (Campbell 356), the environment actually has a large impact on which genes are expressed. Because the Kenyans and Jamaicans live in similar environments, similar genes are expressed. All this relates to the biological theme of the interdependence of nature. The interdependence of natural means that all factors, both abiotic and biotic, impact one another to both allow for life and to shape the dynamics of every community. Kenyans and Jamaicans depend on high altitudes for their excellent running skills. These runners also depend on competition within their community to make them even better runners. Therefore, the real cause of Kenyan and Jamaican dominance in running is actually the environment that they live in.
Aaron Zalewski (bitquest@yahoo.com)
While Kenya is considered to be a “long-distance runner factory”, “ninety percent of top performing Kenyans come from the Kalenjin tribe in the Great Rift Valley region of Western Kenya” (103). From the one fifth that succeeds, most of them are from the Kalenjin tribe. This concentration of talent demonstrates that, contrary to what some may believe, not all Kenyans are natural born runners. The excellent runners we witness smashing records at the Olympics come from only a small portion of the Kenyan population in a specific region. This phenomenon is the result of many generations of natural selection and evolution in response to cultural demands. I agree with Aaron in that the culture of the Kenyans and Jamaicans play the most significant role in altering gene expression over time, but the culture has altered gene expression over time, thus athletes from these regions have succeeded.
ReplyDeleteIn the Kalenjin tribe, the wealth of a man was determined by the size of his herd of cattle. Wealth enhances a man’s ability to court women and helps him achieve his biological goal of surviving and reproducing with success. Therefore, over centuries of male competition for cows, certain traits such as running speed and endurance have emerged as selective advantages. Even within the Kalenjin tribe, factors such as motivation probably separates the top 5%- 10 % of the runners. For instance, Keino “wasn’t the most precocious or ‘natural’ athlete among his peers, but running was simply woven into the fabric of his life” (103).
Similarly, Jamaicans have a good combination of nature and nurture for sprinting. For the nurture aspect, Jamaica is a poor nation, where not everyone has cars, hence people walk and run more often. Jamaicans are involved in sports more than the average nation. For the nature aspect, running is the key to success for many young Jamacians and their environment demands success. As Shenk notes, “climate, media, demographics, nutrition, politics, training, spirituality, education, economics, and folklore” (101) produce athletes in Jamaica.
Generations of natural selection among the Kalenjin tribe may have caused their vital capacity to be higher. According to a study from the African Journal of Biomedical Research, tidal volume is higher in people that exercise than people that do not and the people of the Kalenjin tribe exercise during their day to day tasks, so they exercise more often than most people (http://www.ajol.info/index.php/ajbr/article/viewFile/53962/42504..). According to Campbell, a higher vital capacity could be a result the diaphragm and rib muscles developing more muscle, hence there would be an increase lung capacity after regular exercise (920).
Evolution is “the theory that groups of organisms change with passage of time, mainly as a result of natural selection, so that descendants differ morphologically and physiologically from their ancestors” (http://necsi.edu/projects/evolution/cover/evolution_cover.html). The people of the Kalenjin tribe have adapted over time to their environment and culture; long-distance running is woven into their lives. The high altitude has certainly helped the people of the Kalenjin tribe and Jamaiaca perform better in running, but motivation separates the top athletes. However, the genes cannot be dismissed as a factor because natural selection has played a key role in helping Kenyans and Jamaicans succeed because superior genes do produce a high number of potential candidates from the Kalenjin tribe and Jamaica.
- Akshay Ramachandran (ramachandran.akshay11@gmail.com)