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Archive for January, 2011

Recent readings

The Greatest Show on Earth

It still baffles me that evolution is controversial, but since admittedly, I didn’t know much beyond the basics, I felt I needed to understand the reasoning behind it more.  In this, Richard Dawkins sets forth both some common critiques of evolution as well as the most cited evidence supporting the theory.  Ultimately, the book was convincing, and for many of the main reasons I suspected.  First, the earth is sufficiently old enough to allow for evolution to occur.  We know this from various ways we can date materials, from either radioactive dating, such Carbon 13 (which is renewing), and cessium (?), to dendrochronology, which uses tree rings to link back in time.

Next, Dawkins shows that evolution actually occurs in real time.  He does this by examining certain lizards, though most impressively, detailing the studies on guppies.  Off the coast of South America, a scientist collected and studied guppies.  He sampled guppies from streams that had few predators and from those that had many.  The streams with fewer predators had brighter colors, and vice versa.  Next, he was able to alter the color scheme for guppies depending on how he altered the ratio of predators.  The guppies evolved rather quickly after that.

For further evidence, Dawkins cites how the continents’ structure has changed since the earth began, and how this affected the resulting location for many animals.  He used genetic history as well to show what species were related to each other.  Most interestingly, he addressed the variation between individuals as a species evolved.  Basically, it’s not a bright line mark, which makes sense as the changes are usually not sudden, but rather a slow accumulation of changes over many generations.  This is why scientists often will disagree over what species a fossil will belong to.  This need for classification imposes somewhat artificial distinctions with names when what matters more is the total change over time.

Overall, this books was excellent. The science was straight forward, was more inclusive of other disciplines than I anticipated, and successfully addressed all the arguments creationists use.

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