Penguins & Evolution

How environmental pressures allow the fittest of creatures to survive.

Penguins are one of the best examples of adaptation and evolution. Across sixty million years this bird has undergone radical evolution due to pressures from its environment. This can be seen in the manner in which penguins have become suited to their environment both internally and externally.

The penguin has developed an internal structure which is similar to many birds but with one major difference; the penguin’s internal organs are embedded in many layers of fat which surround the organs and protect them from the harsh cold environment. The penguin has further adapted its abilities to maintain homeostasis and equilibrium from an internal standpoint. Penguins have developed a behavior called preening which is a production of oil from within the body which is excreted from a gland near the base of the penguin’s tail. This gland produces oil that the penguin applies to its feathers. This preening process serves two important functions. The first function is that it allows the bird to move smoothly through the water by waterproofing the feathers. This creates a smooth efficient motion through water. The second function of preening is that it further insulates the penguin’s body from moisture and cold (Cornell , 2014). This preening behavior combined with layers of fat protect the internal organs and their ability to function in the harsh arctic environment.

Organ systems in penguins have evolved to maintain homeostasis and equilibrium in a variety of ways. The more obvious means can be seen in the development of waterproof feathers in order to protect them from freezing water (Cornell , 2014). This adaptation also serves to maintain the bird’s inner temperature such that it will not fall to a dangerous level.

The penguin has sacrificed certain bird attributes in order to become a master swimmer and resistant to the cold. The primary sacrifice is the ability of the bird to fly. Over millions of years penguins adapted to the frigid waters and the best swimmers survived because they could obtain better food supply. As penguins continued in this pursuit they became more adapted to water and swimming than to flight. The penguin’s wings much more closely resemble the fins of a fish than the wings of a bird. According to Brian Handwerk, of National Geographic (2013),

More efficient diving, on the other hand, increased the opportunities to forage for food at depth. A modern emperor penguin can hold its breath for more than 20 minutes and quickly dive to 1,500 feet (450 meters) to feast…Bottom line is that good flippers don’t fly very well (Handwerk, 2013).

Another way in which the penguin has evolved to its environment is through energy expenditure. The cold of the arctic raises metabolic rate in all creatures in order to maintain internal temperature. The penguin is no different except that because it lives in the arctic and swims in the waters it has evolved in manner which the preening and body fat allow the bird to expend less energy. This is also believed to be another reason that the penguin has been forced to give up flight because flying simply takes a lot more energy than swimming (Handwerk, 2013). If penguins flew, they would need to eat larger amounts of food in order to compensate for the energy expenditure of flight.

This would involve a progressive reduction in wing size, which makes diving more efficient and flying less so. Penguin bones also thickened over the ages, as lighter bones that make it easier for birds to fly gave way to more dense bones, which may have helped make them less buoyant for diving (Handwerk, 2013).

The example of the penguin shows that over time the environmental pressures such as cold, cause changes and allow the fittest of creatures to survive (Gregory, 2007). A large part of this process of adaptation is being able to maintain homeostasis and equilibrium. If an organism cannot survive changes that impact these factors it will become extinct. This is why penguins have survived and can continue to survive even with large fluctuation with temperature.

References

Cornell . (2014). Feathers and Plumages. Retrieved from The Cornell Lab of Ornithology: http://www.birds.cornell.edu/AllAboutBirds/studying/feathers/

Gregory, T. R. (2007, November 20). Evolution as Fact, Theory, and Path. Retrieved from Springer Science: http://download.springer.com/static/pdf/196/art%253A10.1007%252Fs12052-007-0001-z.pdf?auth66=1395456547_003513fdf10ecd3dc41aaf2e7e4af6c0&ext=.pdf

Handwerk, B. (2013, May 20). Why Did Penguins Stop Flying? The Answer Is Evolutionary Penguins’ swimming prowess cost them their ability to fly, a new study says. Retrieved from National Geographic: http://news.nationalgeographic.com/news/2013/13/131320-penguin-evolution-science-flight-diving-swimming-wings/

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