Charles Robert Darwin was born 210 years ago today, which seems like a long time to most humans. That time is about a microsecond in the geologic time scale (GTS) that expresses the history of our planet. Would Darwin be impressed by how far our understanding of life has evolved?
In 1837, Darwin wrote in his notes (see image) “I think case must be that one generation should have as many living as now. To do this and to have as many species in same genus (as is) requires extinction . Thus between A + B the immense gap of relation. C + B the finest gradation. B+D rather greater distinction. Thus genera would be formed. Bearing relation” (next page begins) “to ancient types with several extinct forms.”
To be fair, it is likely this thought had occurred to other people before this time, but were never published. It took Darwin, twenty-two years to gather evidence and develop the idea and the courage to publish his most famous work On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life published on November 22, 1859. In 1844, Darwin wrote to Joseph Dalton Hooker, “At last gleams of light have come, & I am almost convinced (quite contrary to opinion I started with) that species are not (it is like confessing a murder) immutable. Heaven forfend me from Lamarck nonsense of a “tendency to progression” “adaptations from the slow willing of animals…”
Darwin opened up a can of worms or should I say bacteria with his theory which is still being debated today. Although the debate today is much different than in Darwin’s time. So like life, knowledge evolves as well. The tree of life looks much different than Darwin’s first drawing.
What strikes me about this modern version of the tree of life is the dominance of bacteria. Bacteria are colored blue, eukaryotes red, and archaea green. This shows the diversity in bacteria, it does not indicate the abundance of bacteria on earth where the biomass has been estimated to be greater that all plants and animals combined. Another interesting fact about bacteria is they evolve at a rate that is observable in a short time-frame. The video below shows bacteria evolving antibiotic resistance in a matter of days.
So the debate continues with many theories on how life evolves, but that is what science is all about, testing theories to find what is the best explanation of reality.
At the end of On the Origin of Species Darwin concluded that:
There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.
“Evolved” in the quote above was the only mention of evolution in the first 5 editions of his book. He finally added the word “evolution” to the sixth edition of his The Origin of Species in 1872 also removing “On” from the title.
Happy birthday to Charles Darwin and the Secular Hub (6 years old).
For more information see Wikipedia’s Portal:Evolutionary biology.