Sunday, December 5, 2010

Life Lines 64


We identify human cultural evolution with basic ideas like the domestication of animals and plants, the invention of the city, the invention of written languages, and the invention of the Golden Rule. We then lead our way to the advocacy of universal human rights in this past century. Each early event helped humanity to prepare for later events. Perhaps in this first century of the third millennium we may see new inventions that make us more respectful and appreciative of human diversity. We might find ways of settling differences without a resort to violence, terrorism, or war. Let us hope we find ways to celebrate and use our common human talents to solve the many problems likely to emerge in the years ahead. I thought a similar approach could be applied to the evolution of life. What were the great inventions of nature that made our present life in all its diversity possible? Here is my list of those great events:
• The formation of complex organic molecules from simple ones by natural processes leading to amino acids, nitrogenous bases, sugars, and simple lipids.
• The invention of chains of nucleotides forming RNA molecules and their capacity to replicate their sequences.
• The invention of chains of nucleotides forming DNA molecules and their capacity to replicate their sequences.
• The invention of the genetic code
• The invention of virus-like systems using proteins to protect their nucleic acid.
• The formation of aggregates providing mutual benefit and acting as cell-like organisms.
• The formation of bacteria-like cells.
• The invention of photosynthesis.
• The invention of abundant energy production by using oxygen to react with small organic molecules.
• The invention of eukaryotic cells having a separate nucleus to house its DNA.
• The invention of meiosis to provide efficient sexual reproduction and genetic diversity.
• The invention of cell adhesives to make colonies of cells.
• The invention of differentiation to make different tissue types possible in a single organism.
• The invention of body plans to make our phyla possible.
• The invention of the kidneys and lungs to make the shift from water to land animals possible.
• The invention of a centralized nervous system and the sense organs to inform it.
• The invention of learning and teaching to by-pass inherited instincts to respond faster to changing environments.
• The invention of self-awareness to make human cultural evolution possible.

As these great inventions are resolved by the end of this century, arguing against evolution by attacking the fossil record will be like arguing today that the earth is the center of the universe and angels push the sun, moon, and planets in circular orbits around us.

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