Galapagos Evolution

Decent Essays
Natural selection can and has been observed in the real world. Examples of change in phenotype frequency of traits in a population as a result of ecological pressures abound, and can be detailed from both extant and extinct species.
To begin, one can always look back to the famed case of the peppered moths of industrial-era London. The light-colored tree bark and lichens of the area were ideal places for the light moths to hide from predators, while dark moths were rare. Dark moths were easier to spot, and would be eaten by birds at higher rates than their light counterparts. As the Industrial Revolution took hold and factories began throwing soot into the surrounding environment, suddenly the darker moths –who had been more prone to predation
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It is well-documented that the finches of the Galapagos, having radiated from a common ancestor from the mainland ages ago, went on to occupy various ecological niches, adapting beak shapes/sizes suitable for their differing diets. Competition between individuals occupying the same geographic area and similar niches can drive the evolution of various morphologies one way or the other, also known as character displacement. In this example, the medium ground finch, Geospiza fortis, population in one of the islands was changed within the span of one generation due to extreme shifts in the environment. During a year of drought that saw the exhaustion of smaller soft seeds as a food source, birds with smaller beaks died out more readily, given they could not handle and break the coating of the larger seeds that remained. Only birds with larger beaks could handle the large seeds, and as such were able to eat and survive to reproduce. As a result, the following generation of finches showed an increase in average beak size from the previous generation. The inverse occurred when abundant rain the following year saw the scarcity of large seeds and the increased fitness of smaller-beaked…show more content…
Anything that improves a rudimentary structure is better than nothing, and as such, those changes will be selected for over time.
I was glad to see the day’s topic on irreducible complexity covered, since it’s a concept I’ve been aquainted with previously. Having read the book “Finding Darwin’s God,” I knew of the arguments about irreducible complexity, and was already introduced to the fossil records and empirical data sets that refuted this argument.
When Darwin claimed to find the evolution of the eye by natural selection “absurd in the highest degree,” he was conceding that popular opinion would sway in this direction. He was admitting that his ideas were indeed, hard to swallow and a bit counterintuitive for the audience of the time. But, he continues on in the text, so was the argument for the Earth being round, and revolving around the Sun instead of the other way around. His words, taken out of their satirical context, can be read as incriminating his own theory, but obviously that’s not the
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