The Argument-
David Shenk states that “academic clusters are not genetic, but systemic” (101), which is supported by the immense success of sprinters from Jamaica. These populations of athletes indicate that “sports excellence commonly emerges in geographic clusters” (101). Therefore, species do not evolve as a whole over time, but rather evolve within their own populations, each population evolving in a different manner depending on its geographic location. How can this population evolution be applied to other organisms and applied to the theme of evolution? In what environments could different populations have existed in order for similar animals to have so many different variations, such as canines evolving into species that are as diverse as wolves and coyotes are from poodles and chihuahuas? On the other side of evolution and population success, how can the extinction vortex model of decreasing genetic variability be justified along with GxE gene expression and the effect of environmental factors on populations? Should environmental factors beneficial to small populations be enough to save populations of small genetic variability from extinction? Refer to Chapter 52 of Campbell to relate to population ecology, and chapter 56 regarding the extinction vortex.
Aaron Zalewski (bitquest@yahoo.com)
-The Argument
ReplyDeleteShenk’s discussion about the success of Jamaican sprinters underlies the importance of the abiotic and biotic factors that organisms interact with. Due to “climate, media, demographics, nutrition, politics, training, spirituality, education” as well as other people, dispersal takes place and individuals begin moving from area of high population density to a “poor, underdeveloped nation of 2.8 million people” (100-101). For most organisms, Campbell stresses that habitat selection is attributed to temperature, water, salinity, and sunlight, as well as the organisms of different species. Considering Jamaica’s geographical location near the equator, the heat and temperature might possibly account for the activation of “gene variant ACTN3” that is found in most Jamaicans according to Shenk (101).
In a Sports Medicine journal article on EBSCOhost, “Induction and Decay of Short-Term Heat Acclimation in Moderately and Highly Trained Athletes,” biologists found that the average athlete has more trouble adapting to heat than the highly-trained (Olympic-type) athlete. The article stresses how gene regulation and the activation of gene variant ACTN3 that may be the cause of the increase athletic ability of Jamaicans can be based on the location. Considering how athletes must acclimate to an increasing body temperature during exercise, the ability to adapt to the heat and temperature for Jamaicans occurs at a faster rate than most Olympians.
The variations in wolves and coyotes from poodles and Chihuahuas can once again be related to the interaction with abiotic and biotic factors, especially the interaction that poodles and Chihuahuas have with humans. Gene regulation play important role in determining the physical traits of poodles and Chihuahua considering theses organisms are far more domesticated by humans than coyotes or wolves. Shenk’s GxE gene expression shows how the environment for poodles and Chihuahuas had promoted domestication and a divergence from the wolves and coyotes that lack human interaction in their environment as poodles and Chihuahuas have.
The extinction vortex attributes the decrease in the number of organisms of a population to the loss of genetic variation and inbreeding. In order to survive in a changing environment that could harm organisms through disease or the introduction of a new species, populations will have undergo gene regulation if genetic variation isn’t possible in an extinction vortex. Gene regulation allows populations to survive and with a thriving population, an increase in population density promotes dispersal. Many populations avoid the doomed extinction vortex due to gene regulation and meet the standards of the carrying capacity. Gene regulation by the changing environment induces dispersal and accounts for why Americans do not share similar appearances to Jamaicans as well as athletic ability that has allowed the Jamaicans to succeed during the Olympic Games.
-Trish Chari (trishtennis@gmail.com)