Considering Evolution of Human Skin: A Biological Perspective

This essay delves into the evolution of human skin, highlighting its adaptability and the influence of natural selection. It begins by identifying the human skin as a key phenotypic trait, with pigmentation and heat distribution as critical features. The essay discusses how the original dark skin of early humans was associated with the loss of body hair and how melanin pigmentation was maintained by natural selection. It further explains how human's use of clothing and shelter lessened the impact of natural selection on skin. The essay uses the polar bear as a species of choice, illustrating its adaptations to the arctic environment, particularly its black skin on the nose and footpads for absorbing sunlight and white fur for camouflage. It provides an overview of the evolutionary divergence of polar bears from brown bears and the genetic changes that led to these adaptations, including genes related to fat regulation and cold tolerance. The essay concludes by emphasizing evolution as a continuous process observed across both plant and animal species.

Running head: CONSIDERING EVOLUTION OF THE HUMAN SKIN 1
Considering Evolution of the Human Skin
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CONSIDERING EVOLUTION OF THE HUMAN SKIN 2
Considering Evolution of the Human Skin
The skin of human origin is the most identifiable aspect of the human phenotype. It is
easily distinguished because of its unaided appearance, greatly facilitated by the abilities to
distribute heat of the body through sweating and various range of genetically determined colors
of the skin in a single species. For example, the dark skin was the original state of genus homo
which was greatly associated by loss of hair of the body. On the other hand, pigmentation of
melanin has been maintained by the natural selection. Over the years, human became
opinionated in protecting themselves from the harsh environment when they invented clothing
and shelter, thus they reduced the level of the impact of natural selection on human skin.
The species of choice is polar bears. Polar bears have skin visibly only on the nose and
footpads with a black color and they are well adapted to live in the arctic regions where there is
so much cold. The black color makes it possible for the bear to absorb energy sunlight for the
purposes of warming the body. The other defining characteristic is that their body is completely
furred white apart from the footpads and the nose. Adaptations of the polar bears were because
of evolution specifically to the Arctic generations that were less than 20,500, coming from the
brown bears not long ago than it is claimed (Liu et al., 2014). According to Arctic Research
Centre (2019), the two species of bears diverged hundred thousand of years ago. The species has
evolved progressively from brown furred bear to white- the absolute color that is likely to merge
with the ice covering surrounding they inhabit. The researchers have it that the brown bear
moved to the north region when the climate became slightly warm in the north after a cold period
began in their initial habitats. It is probable that a group of brown bears might have been isolated
and thus compelled to rapidly adapt to the new conditions that were characterized by colder
conditions (Drosophila 12 Genomes Consortium, 2007). In other words, changes in the color of

CONSIDERING EVOLUTION OF THE HUMAN SKIN 3
the fur from brown color to white was because of change in the genes. It is possible then to
conclude that the selection pressure: natural selection contributed to gene changes that were
responsible for transport of fat regulation in the blood and breakdown of fats monitoring in the
body.
Polar bears have also developed a gene that is identical to humans, which enhances
coding of the most essential protein, as a result, polar bears have adapted to very cold conditions
in the arctic regions unlike the brown bears (Cahill et al., 2015).
In conclusion, evolution is a notable part of any given species in the given environment
or surrounding. It is undoubted that evolution will never stop provided the earth still exists, it is a
continuous process that is observed and will continue to be observed in both plants and animal
species.

CONSIDERING EVOLUTION OF THE HUMAN SKIN 4
References
Arctic Research Centre. (2019, June 13). From brown to white – evolution of the polar bear.
Retrieved from http://arctic.au.dk/news-and-events/news/show/artikel/from-brown-to-
white-evolution-of-the-polar-bear/
Cahill, J. A., Stirling, I., Kistler, L., Salamzade, R., Ersmark, E., Fulton, T. L., ... & Shapiro, B.
(2015). Genomic evidence of geographically widespread effect of gene flow from polar
bears into brown bears. Molecular ecology, 24(6), 1205-1217.
Drosophila 12 Genomes Consortium. (2007). Evolution of genes and genomes on the Drosophila
phylogeny. Nature, 450(7167), 203.
Liu, S., Lorenzen, E. D., Fumagalli, M., Li, B., Harris, K., Xiong, Z., ... & Wray, G. (2014).
Population genomics reveal recent speciation and rapid evolutionary adaptation in polar
bears. Cell, 157(4), 785-794.