Nature of the Earth

        “The nature of life on earth and the quest for life elsewhere are two sides of the same question: the search for who we are.”  Sagan uses a discussion of Earth’s development of life to introduce a consideration of how life may appear elsewhere in the universe, and how all of these things are related.  This episode I found to be very interesting for many reasons, the new theories posed as to how we were formed and whether or not we are alone in the universe.  The title of this episode is also very interesting and describes what the episode will be about using a metaphor, which Sagan uses to contrast the one “voice” we know, Earth’s evolution and intensely connected life, to the possibilities out there in space.  Are we alone, “…or is there a cosmic fugue, a billion different voices playing the life music of the galaxy?”  It is interesting that Sagan locates us in a moment of history in 12th century Japan, where one clan is wiped out by another, resulting in the suicide of the clan’s child emperor.  The sudden jump to a mythologized history is a little odd, at first, until we see where it’s going: the inland sea where these folks died now has crabs that appear to have the faces of samurai on their backs.  Using this jumping-off point, Sagan takes us through a gentle example of artificial selection: the crabs that appeared to have human faces were thrown back by the fishermen and reproduced, but the ones without the eerie face-markings were eaten.  Therefore, over time, we ended up with more crabs that had the markings than not.  The crab example eases us into the theory of evolution.

        This episode of the cosmos contains many theories as to what evolution is, how the universe was made, artificial selection, natural selection, and cellular biology.  Sagan states that evolution is not a theory, but a fact and that the world around us is always changing and that we must go back in time to help understand the future.  This episode describes how all things, humans, plants, and all forms of matter are somehow related and how they all tie back together to the beginning of time.  This is how evolution happened, with small forms of cells evolving to form different types of organisms.  This then leads to the theories of natural and artificial selection.  Natural selection being where all organisms adapt to the environment as it changes around them and artificial selection being where certain and specific traits are passed on from generation to generation, similar to intentional breeding.  The differences between the two have led to new conclusions over time where many philosophers will agree with the idea of natural selection as opposed to artificial selection because in order for organisms to survive, they must adapt.  As organisms adapt, we learn how cells work and the different functions and types of cells that there are in these different types of organisms.  No matter how complex the cell is, Sagan emphasizes the fact that these cells containing all forms of DNA, are what tie all forms of matter back together to be related in certain type of way.  These theories all play an important role in our society today and in the significance of understanding the future and what is still yet to come.

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