By Casey Peters
Happy Darwin Day to everyone!! It’s Darwin’s birthday, so I thought I would commemorate the occasion with a blog post.
I have recently read two wonderful books about Darwin’s intellectual predecessors and the development of the ideas the prepared the ground in which Darwin’s great idea could take root and grow. They are Darwin’s Ghosts by Rebecca Stott and Darwin’s Century by Loren Eiseley. I highly recommend both. They are beautifully written and offer a deep appreciation for how important the complex mixture of culture, philosophy, science, and history is for understanding how people think and develop new ways of understanding the world that they experience. Both books provide a deeply satisfying context in which to place Darwin and his achievements, while also celebrating the contributions of many other brilliant and courageous people.
In Darwin’s time, species change by natural selection was in the air. The concept of geological timescales, the recognition of the reality of species extinction, the observation of global patterns of diversity, the careful description of natural variation within species, advances comparative anatomy, systematics, and embryology - all of these and more made the eventual theory of natural selection inevitable. If Darwin hadn’t thought of it, others would have done so independently. In fact several people did – famously including Alfred Russell Wallace, and less famously Patrick Matthew.
Darwin’s great genius was how thoroughly and compellingly he presented his argument, and how deeply he saw its implications. Natural selection is a fairly simple concept, but it explains so many different aspects of the natural world. It is astonishing how completely Darwin showed how evolution by natural selection can account for not just the diversity of life, but also biogeographical patterns, comparative anatomy, behavior and instinct, the apparent design of organisms to fit their environments, and so much more. He also plainly and honestly identified gaps in knowledge where serious contradictions to his theory might lie, effectively laying the way for future research.
When I read On the Origins of Species (just a few years ago*) I was shocked by how modern it seems. I was also surprised by how much ecology it contains. Ecology as a discipline did not have a name until 1866 (7 years after the first edition On the Origin of Species) and didn’t really become an experimental or predictive science (something it is still struggling to do well) until the mid-1900s, but Darwin describes many ideas central to modern ecology. He writes beautifully about the interaction of species with their environment and with each other. He writes about distribution and dispersal, population dynamics, and the concept of the niche. He makes comparison between different ecosystems regarding the strength of natural selection in those environments and the consequences of those differences on observable patterns of diversity. One of the most famous sentences in all of The Origin of Species is a beautiful description of ecological interactions and their evolutionary causes and consequences:
It is interesting to contemplate a tangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent upon each other in so complex a manner, have all been produced by laws acting around us.
This reminds me of G. Evelyn Hutchison’s description of evolution as a play that takes place on the ecological stage. It adds drama and depth to our experience of the natural world, and it encourages me to get outside to experience, appreciate, and participate in the product of that drama.
Thank you Charles Darwin, thank you those who came before him, and thank you to those who followed and continue to follow in his footsteps.
*I’m actually surprised that I earned a degree in biology without having to read On the Origin of Species. I would guess that many professional biologists haven’t read it, which is a shame. It is a truly amazing work that deserve to be read today.
By Casey Peters
The Christmas tree is one of the central totems of the holiday season. A wide variety of conifer species are commonly sold as Christmas Trees around the world including firs, douglas-firs, spruces, pines, and cypresses. But I would like to call attention to a lesser known genus of tree that deserves greater attention* during the holiday season, the yew (Taxus spp.).
The Common Yew (Taxus baccata) pre-dates Christmas as a symbol of wintertime celebration. Pagan festivals honoring the winter solstice such as the Roman festival of Saturnalia used evergreen plants, persistent through the winter months, as a symbol of life. When the Christian holiday co-opted those pagan traditions, the yew was imbued (imb-yewed?) with the significance of that particular brand of religion. According to Wikipedia, “Yew trees continually put out new stems which coalesce with the existing trunk resulting in trees of great age. The merging of old and decaying wood with vibrant young shoots has led to the yew being traditionally associated with reincarnation and immortality.” Ancient yews are often found in churchyards and cemeteries in Northwestern Europe, and the largest are hollowed out to contain chapels.
When contemplating a holiday-appropriate blog post for this week, the first thing that came to mind was the Turkey. Turkeys are of course the centerpiece of the traditional Thanksgiving feast, but are they really interesting enough to spend five minutes reading about? After all you are quite busy today. Well, Benjamin Franklin thought they were pretty impressive. Legend has it he advocated for the noble Turkey as our national bird over the Bald Eagle. While this may largely be an American myth, his writing on the subject shows he clearly had great respect for the bird.
“For the Truth the Turkey is in Comparison a much more respectable Bird [than the Bald Eagle], and withal a true original Native of America… He is besides, though a little vain & silly, a Bird of Courage, and would not hesitate to attack a Grenadier of the British Guards who should presume to invade his Farm Yard with a red Coat on.”
- Benjamin Franklin
It might be science, it might be nons(ci)ense, but it still smells.