MacArthur's words still resonate 40 years on

I recently received an old library copy of “Geographical Ecology: Patterns in the Distribution of Species” by Robert MacArthur (1972). It’s the last book that MacArthur wrote before his early death to cancer. It is an ambitious book that connects repeated ecological patterns to mechanisms as broad as the earth’s rotations (producing climate as we experience it) and as focused as organismal behaviour.

But honestly, the thing that has struck me most so far as I read is the timelessness and wisdom in MacArthur's introduction. Issues ranging from focusing on questions versus systems, the value of repeated patterns, complexity, and what generality really means, aren't at all new.

“To do science is to search for repeated patterns, not simply to accumulate facts, and to do the science of geographical ecology is to search for patterns of plant and animal life that can be put on a map. The person best equipped to do this is the naturalist who loves to note changes in bird life up a mountainside, or changes in plant life from mainland to island, or changes in butterflies from temperature to tropics. But not all naturalists want to do science; many take refuge in nature’s complexity as a justification to oppose any search for patterns. This book is addressed to those who do wish to do science. Doing science is not such a barrier to feeling or such a dehumanizing influence as is often made out. It does not take the beauty from nature. The only rules of scientific method are honest observations and accurate logic. To be great it must also be guided by a judgment, almost an instinct, for what is worth studying. No one should feel that honest and accuracy guided by imagination have any power to take away nature’s beauty.

Science should be general in its principles. A well-known ecologist remarked that any pattern visible in my birds but not in his Paramecium would not be interesting, because, I presume, he felt it would not be general. The theme running through this book is that the structure of the environment, the morphology of the species, the economics of species behaviour, and the dynamics of population changes are the four essential ingredients of all interesting biogeographic patterns. Any good generalization will be likely to build in all these ingredients, and a bird pattern would only be expected to look like that of a Paramecium if birds and Paramecium had the same morphology, economics, and dynamics, and found themselves in environments of the same structure.”
--Robert MacArthur

It's interesting that an introduction written in 1972 is so relevant that it could have been written today. The pessimistic view is that ecology is just iterating through the same problems and solutions, or progress is slow. Or maybe classic books remain as classics because their authors understood and explored the issues at the core of the science and had the benefit of being there in the formative years. It's fun to see that when MacArthur thanks particularly four friends who influenced his work most, he means G. Evelyn Hutchinson, E.O. Wilson, Richard Levins, and Jared Diamond. I suppose any book influenced by the combination of all these scientists and written by MacArthur will always have something interesting to say. 

Understanding modern human society through the lens of evolution

Book review of Edmund Russell’s ‘Evolutionary History’

We often think about the ways in which evolution has shaped this world, from the amazing diversity of cichlid fishes in the African Great Lakes, to Australian marsupials that seem to replicate strategies that placental mammals have evolved elsewhere (e.g., Tasmanian tiger and the North American wolf). We even look at our own bodies or behaviors to find evolution’s imprint –why do I have a non-functional appendix attached to my intestine? However, we seldom look to important events in human history to examine the effects of evolution, yet, according to Edmund Russell, human history can be better understood through evolution –like my appendix.

Russell is advocating for a new field of inquiry within the study of human history –namely, evolutionary history. When I first read the book jacket, I must admit that I was skeptical. However, this book makes the compelling case that historians gain a much fuller understanding past events by including evolution. Russell’s main claim is that modern civilization is the product of an evolution revolution. Even Russell’s unremarkable dog “Riley, like all dogs, is a testament to the extraordinary power of human beings to shape the evolution of other species”. While citing dogs may seem like a trivial example, it was coevolution that shaped this relationship. Wolves that were less aggressive and less fearful, which tend to be more puppy-like, found benefits by associating with human groups. Human groups that tolerated the presence of these wolves were likely alerted to approaching threats. Even the fact that dogs bark is a product of this relationship. This evolution revolution can similarly explain the domestication of other animals and plants, and ultimately produces the necessary conditions for permanent large settlements.

An important and intriguing underlying theme of this book is that these evolutionary revolutions are not often the product of conscious effort. We are used to the narrative that highlights humans as selecting individuals and driving the evolution towards some goal. But this would require early peoples knowing what they wanted in the end, having a specific goal. In the dog example, do we really think that early humans thought ‘hey, I would like a poodle’? No, the reality is that canines and human changed with one another producing a mutually beneficial outcome. Even the domestication of many of the earliest crop species likely resulted from lazy and sloppy humans. Lazy because humans probably harvested the easiest, most accessible fruits and seeds –selecting for bigger, easily removed fruits that ripened at the same time. Sloppy because seeds were discarded around settlements. Then that laziness again means we looked to those nearby plants for harvesting. Thus evolution has continually informed the development of human civilization and produced the much of the cultural norms today.

While modern cultures may consciously drive evolution through selective breeding and genetic engineering, we are immersed in an evolving world. Diseases that are resistant to drugs, pest that are immune to pesticides, and commercial fish that are now smaller and reproduce earlier are examples of important evolutionary changes that affect human activities and economics. Russell provides evidence that evolution is in part responsible for the industrial revolution, due to some varieties of cotton evolving particular features.

Taken all together, Russell admirably succeeds in his goal of convincing the reader that evolution has influenced much of human civilization. Moreover, his intended audience of historians should be re-assessing previous explanations of important human events by asking the basic question: how has evolutionary change influenced major changes in human history.

Edmund Russell. 2011. Evolutionary History. Cambridge University Press.