COVERS
Endless Forms
Evolution As A Force that Never Stops By Alan Yang “[F]rom so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.� - Charles Darwin, On the Origin of Species Evolution is responsible for the remarkable diversity of life forms that inhabit our planet, from angler fish and venus fly traps to sea sponges, pterodactyls, and humans. Over a century ago, Charles Darwin famously set forth his theory of evolution via natural selection in his book On the Origin of Species; the theory is still widely applied and accepted today. Drawing on the works of other great minds, Darwin argued that those organisms best suited to their environment are more likely to survive and reproduce than those less well-adapted to their environment. As a result, the frequency of the genes of the better-adapted organisms will increase in the overall gene pool, and these changes in gene
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BREVIA Fall 2016
frequencies over time lead to species differentiation and evolution. Moreover, evolution happens most rapidly when there is significant selection pressure-that is, when organisms live in an environment where poorly-adapted creatures quickly die out. Scarcity of food, for example, exerts such selection pressure and forces populations to evolve faster. Although Darwin set forth this general framework for thinking about evolution long ago, there are still aspects of evolution that we do not understand today. One unanswered question is whether evolution ever stops: whether natural selection can create an species that is perfectly adapted to its environment and will not change further. Professor Richard Lenski from the University of Michigan thinks he has the answer after a 27-year-long (and counting!) experiment.1 Although the evolution of humans and other slowly-reproducing animals often takes hundreds of thousands of years, Professor Lenski wanted to be able to observe evolution taking place in real time. Thus in 1988, Professor Lenski set in motion a long-term experiment with E. coli bacteria that would allow
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