A multi-year study by Peter and Rosemary Grant documented how finch beaks differ from short, narrow and shallow to long, wide and deep, the differences in dimensions correlating with the birds’ ability to harvest different types of seeds. In 1977 the [Galapagos] islands experienced a severe drought. Food was so scarce that no birds produced young that year. Only 15 percent of the adults survived to reproduce when the rains finally came. Those that survived had longer, wider, deeper beaks that enabled them to crack the tougher seeds in the seed bank. Their offspring inherited that trait. In 1983 a continuing deluge of rain carpeted the islands with grass, providing an abundance of small soft seeds. Finches with smaller beaks were more able to harvest the available seeds; many produced multiple sets of offspring. After this time the average bird in the population had a shorter, narrower beak, thus reversing the change that had occurred during the drought. As Reznick trenchantly observes, “This reversal is telling because it says that there is not a universal ‘best’ bird. Whether a given feature of an individual gives it an advantage of another depends entirely on the circumstance, be it drought or flood. This is a good illustration of the fact that evolution does not progress in any particular direction, but is rather a response to present conditions in the moment. If conditions change, then so will the selection experienced by populations. If conditions remain constant, it is possible there will be no evolution at all.” [P. 91-92]
Reading: From Finding Beauty in a Broken World by Terry Tempest Williams
In 1950 government agents proposed to get rid of prairie dogs on some parts of the Navaho reservation in order to protect the roots of sparse desert grasses and thereby maintain some marginal grazing for sheep.
The Navajo elders objected, insisting, “If you kill all the prairie dogs, there will be no one to cry for the rain.”
The amused officials assured the Navajo that there was no correlation between rain and prairie dogs and carried out their plan. The outcome was surprising only to the federal officials. The desert near Chilchinbito, Arizona, became a virtual wasteland. Without the ground-turning process of the burrowing animals, the soil became solidly packed, unable to accept rain. Hard pan. The result; fierce runoff whenever it rained. What little vegetation remained was carried away by flash floods and a legacy of erosion. [p. 87]
Sermon- Evolving Together
When Darwin developed his theory of evolution, it didn’t come to him in one “aha” moment, but emerged over years of observing the natural world. Just after college he famously spent 5 years on the HMS Beagle as a self-appointed naturalist doing those things many of us did as kids, turning over rocks, watching critters, collecting fossils, catching tadpoles in a jar, or just staring at that natural world around him as the Beagle charted the coast of South America. Now what he did that most of us didn’t do was keep a series of meticulous leather bound diaries of all he saw, and how it all fit together. For twenty some years he observed and wrote and thought until in his 50s he finally published “The Origin of Species.”
At the time he wrote this book, the prevailing scientific view was that “Each species came about by an independent act of creation.” [Johnson p. 33] That is to say, each individual species was created exactly as it is today by the hand of God. This theory is called “Special Creation.” Darwin proposed the radical new idea that species changed gradually over time without any supernatural intervention. At first Darwin called this theory “Descent with Modification” because common species can be traced back to common ancestors found in the fossil record. As natural variations occur in the species, some of these modifications would be beneficial, some would not. Darwin Wrote “This preservation of favorable variation and the rejection of injurious variation, I call Natural Selection…We see nothing of these slow changes in progress, until the hand of time has marked the long lapse of ages” [Johnson p.28] This idea shook the foundations of both the religious and scientific establishments which were committed to the “special creation” theory.
By 2015 the entire scientific community has rallied around Darwin’s “Natural Selection” theory, but the theory of special creation can still be found in churches, and on school boards, and in the houses of Congress. This is why once a year we join with other communities of faith to remind ourselves, to remind the world, that scientific and religious truth are not enemies, but together weave our understanding of the life we share. On Evolution Weekend, we tell true stories written in the body of the world.
Darwin wrote in the final paragraph of his On the Origin of Species (1859):
“It is interesting to contemplate an entangled 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 on each other in so complex a manner, have all been produced by laws acting around us.”
He could have been talking about the story we just heard about the Mangrove tangle, and there are in fact mangroves in some of the places he traveled in his 5 years on the Beagle. Although all those little critters who, in our story, said “I could live here and find food and safety” are in the real world not individuals making a life choice, these are the species whose grandparents and great great grandparents co-evolved with the mangrove trees, and with the bacteria that live there, and the whole tangle of beings who not only live together but change and are changed by one another over thousands of years of living in natural community.
By way of contrast, my front window looks out on a number of trees and bushes full of seeds and berries, but none of the critters in my neighborhood seem at all interested in eating them. That’s because these trees and shrubs were purchased by some landscaper or arborist and planted there as relative strangers to the natural community. My squirrels and juncos and cardinals did not co-evolve with those plants, and so they remain as strangers, and their fruit goes uneaten.
“Evolution is a relational Process” says Elizabeth Johnson, Theologian and author this book Ask the Beasts: Darwin and the God of Love. [p. 120] The plants and critters who live in Darwin’s tangled bank, are “dependent on each other in so complex a manner.” As Darwin wrote “… how infinitely complex and close-fitting are the mutual relations of all organic beings to each other and to their physical conditions of life” [p. 121]
These beings shape and are shaped by one another not only un competition for scarce natural resources, like the finches on the Galapagos Islands - evolving their beaks in local niches based on what food was available, and what beak shape they need to better access that food, but consider also clams or crabs or lobsters, with soft vulnerable bodies, who evolved hard shells or carapaces, for protection from their “predators, which followed suit by evolving body parts that pierce, chew, or even saw through these protections.”[i]
My friend and colleague Scott Prinster offered a more gentle collaborative example as well between “hummingbirds and honeysuckle. The flowers evolve nectar that attracts the birds and fits their dietary needs (hummingbirds need enormous amounts of sugar to fly and keep their bodies from overheating). The flowers have also developed bright colors and unusually ornate shapes to attract the birds, and they bloom during the hummingbirds' breeding season. In return, the hummingbirds pollinate the flowers, which are not as attractive to bees as other kinds of flowers.”
Darwin’s theory is a profoundly relational one.
Unfortunately, this idea of the “survival of the fittest” which did not even appear in Darwin’s work until the 5th edition of his famous book, has turned our popular understanding of the profoundly relational process of evolution, into a social theory that prizes the strength of the individual. In Darwin’s day, British Political Theorist Herbert Spencer co-opted the theory of descent by modification into a political theory in which there are inevitable winners and losers in human society. “Social Darwinism” holds that “the powerful in society are innately better than the weak; that their success is proof of their superiority.” Often Alfred Lord Tennyson's poetic line “Nature, red in tooth and claw”[ii] is used to suggest the violence of the natural world, to convince us that “only the strong survive.”
But remember, evolution is not about the survival of the individual. It is about the survival of a species, a community of species, of life itself. As Rosemary and Peter Grant’s work with finches points out, there is no single best bird. Instead the many varieties of life’s creative expression, ensure the survival of whatever form is most suited to this time and place in an ever changing world. Survival in nature is not limited to the arms race between predator and prey; sometimes it is cooperation, sharing or altruism that allows life to succeed. Did you know that Vampire bats will feed a starving bat who is not even related to them?[iii] As Elizabeth Johnson puts it: “Rather than existing as independent operators, all organisms live in intricate systems consisting of many such dynamic interchanges. Each ecosystem is unique. Each has intrinsic value … in a particular time and place...” [p. 119]
This misuse of Darwin’s theory not only seems to support the kind of escalating economic inequalities that UU’s around the country have chosen to study and confront together, but it also gives us the wrong picture of our role in the web of life. When we learn evolution in school (if we are lucky enough to live in a school district that allows it) we tend to study a single branch of the tree of life as it grows and branches and thrives or ends. Think of that classic drawing of the progression from ape to Homo Saipan. When we look at evolution this way it’s difficult to see the complex web of relationships by which species- plant, animal, bacterial, evolve together.
Consider keystone species. This concept was first put forth by zoologist Robert T. Paine In 1969. Like a keystone in an arch, these species, when removed, cause the whole eco-system to collapse. Paine tested this theory by removing certain species from different eco-systems, and leaving other similar eco-systems alone. The systems where he removed the keystone species collapsed. For example, in the system where he removed the sea star from its rocky costal habitat, 7 out of 15 species he measured disappeared. While in the control systems all the species persisted.[iv] The groundhog, from our first reading, is a keystone species. Williams writes “More than 200 species of wildlife have been associated with prairie dog towns, with over 140 species benefiting directly, including bison, pronghorn antelope, burrowing owls, pocket mice, deer mice, ants, black widow spiders, horned larks, and many predators such as rattlesnakes, golden eagles, badgers, bobcats, weasels, foxes, coyotes and especially black-footed ferrets.” When prairie dogs are taken out of their eco-system, 9 vertebrate species disappear or sharply shrink in numbers. We evolve together. We live and die together.
Recently Sen. Lisa Murkowski was interviewed about President Obama’s plans to designate 12 million acres of Alaska's Arctic National Wildlife Refuge as wilderness. She responded in part: “There's so much focus on the wildlife, on the polar bear and the critters and the birds. And they are important. Don't get me wrong. But equally important - more important - is the obligation that we have to the people who live there” [v] This is a point many politicians have made over the years when someone tries to protect an eco-system in jeopardy. But I believe this poses a false dichotomy. It ignores how deeply we humans are woven into the web of life, how we too have co-evolved with plants, and animals, and bacteria. We may think we don’t need the groundhog, which ruins our golf courses, and might or might not limit the amount of grass our sheep can graze on, but not even humans can thrive on a hard-pan desert. The political rhetoric pitting Alaskan wildlife against human welfare ignores the complexity of this web of relationships, and the thousands of generations it took for us to weave the web of life as we know it. If we remove keystone species, of we tip an eco-system past the point where it can recover, it will take thousands more generations for a new eco-system to evolve.
I think the story of the Mangrove which found its niche as a genus of tree that can survive in salt-water is beautiful and inspiring. The birds, and crustaceans and sea mammals that shelter there and eat there have evolved together to share that habitat. The ecosystem shelters and feeds them, and they in turn feed it. It’s so elegant; the way mangrove islands protect our coral reefs from the silt runoff from clearcutting, and filter pollutants that run off our roads and farms. The mangrove islands absorb some of the wave strength of storms, protecting our coasts. The mangrove tree and all its living community survived because of the success of their interrelatedness. When we say “survival of the fittest” we are not talking about the kind of “fit” you get at a gym, a;; much strength and power, but living beings who “fit” together like an incredibly complex puzzle.
Perhaps that complexity is why we illustrate the history of our human evolution as one line of hominids marching in procession, without pausing to fill in the whole picture. If we really understood the complexity of each eco-systems that created us, we might wonder about the complexity of the eco-systems we inhabit now : the groundhogs we exterminate to make room for our grazing animals, or the mangrove forests we cut down to make shrimp farms. If we really took the time to understand this interdependent web of all existence of which we are a part[vi], we would be humbled by it I think. Understanding the true complexity of our world is not only a spiritual act of respect and gratitude, but pragmatic act. We provide a more accurate blueprint for our own survival when we see the web than when we imagine that we who are most fit can somehow survive alone.
So if this sermon has inspired you to boycott shrimp that is farmed unsustainably, or if it inspires you to lobby your Fish and Wildlife service to protect the Utah prairie dog from extinction, that’s wonderful. But just as important, I hope you will look with new eyes at the eco-system you live in, at the ones you visit on vacation, at the eco-systems where your food is harvested. To look with humility and awe at their beautiful complexity, and with gratitude for our living community which forms us and shelters us and shaped us just like that tangled bank.
Endnotes
[i] Thanks again to the Rev. Scott Prinster for this
[ii] In Memoriam A. H. H., 1850. The quotation comes in Canto 56 (it is a very long poem)
[iii] Jerry Wilkinson, chair of biology at the University of Maryland-College Park,http://www.radiolab.org/story/105440-blood-buddies/
[iv] http://science.howstuffworks.com/environmental/conservation/issues/keystone-species-extinct.htm
[v] http://www.npr.org/2015/01/27/381783164/sen-murkowski-critical-of-proposed-plan-for-arctic-national-wildlife-refuge
[vi] http://www.uua.org/beliefs/principles/index.shtml
