Cosmos: "Some of the Things That Molecules Do"

Original Air Date:  March 16, 2014

It's been a hectic week at the Scott household, so I will try to make up both of the past two episodes of Cosmos today.

Neil deGrasse Tyson does his best Liam Neeson/Jack London impression has he talks about how wolves evolved into dogs through a decrease in stress hormones and eventual domestication by early humans.  Neil describes what happens as artificial selection, as humans control the selection and breeding of dogs.  The reason why there are shepherds, collies, yorkies and pitbulls is because humanity bred wolves into desirable dogs.

Neil goes on to describe natural selection.  He does this by taking our Spaceship of the Imagination inside an ancient bear.  Neil describes how DNA is split and copied when producing reproductive cells, and how that copied DNA can have "proofreading" errors, causing mutations.  Some mutations, Neil points out, are harmless, some are deadly, and others give organisms an advantage.  Our example bear gives birth to a white furred offspring.  That white bear succeeds better in the snowy environs of the ice age.  The bear and its descendents prosper, leading to the creation of the polar bear.

The show goes on to explain that humanity evolved, too.  Darwin's theory of this evolution, he admits, is controversial.  He knows that it is embarrassing for us to admit their relationship to the ape.  It's even stranger to think of our relationship to trees, which exists at the basic level of sugar digestion.

Neil deconstructs Intellectual Design's proof of a great designer by explaining that evolution can and did create the human eye.  He explains how the eye evolved from a sensitive light area on the earliest of bacterium to the intricate eye of a fish, and why a human eye will never be as efficient because it first developed for seeing underwater.

As a Christian, it frustrates me that my compatriots have such a hard time accepting the facts of evolution.  I understand the desire to hold to the creation story in Genesis, because accepting that story as a parable opens the entire Bible, even the death and resurrection of Christ, to scrutiny. But I believe in a God that allows both to happen.  And that's all I am going to say about that.

Silly ol' waterbear!

The show then talks about the Five Great Extinctions, focusing on the worst of them all -- the Permian event.  It began with mass volcanic eruptions and ended with the extension of 90% of the species on Earth.   Through each of the extinctions, though, one of the lifeforms that survived was one you probably never heard of:  the teeny tardigrade.  The tardigrade can survive in a multitude of extreme conditions, from ice to excessive heat.

The existence of the tardigrade does allow scientists to speculate that life can exist in other extreme conditions, like other planets.  Like the frigid moon Titan, for example, where all water is frozen and it rains methane.  Neil takes the Spaceship of Imagination to Titan and asks:  could life exist here?  Life like none we have ever seen?

Finally, we are treated with an animation from the original Cosmos, that showed a potential unbroken line of life from the earliest microbes to humanity

Another great episode, this time focusing on Earth and it's life rather than the rest of the cosmos.  In order to understand "out there", we must first understand here.