Evolutionary biologists are storytellers. We are in the business of telling more or less informed stories about the evolution of lineages. But we operate under a curse. What we are most interested in, our eyes can’t see, and what we can see is literally beside the point. We can glimpse evolution’s invisible highways only through its observable byways. We can access the invisible realm of ancestors and descendants only indirectly through inferences based on the visible traits of taxa in the realm of collateral relatives. It is this unique mix of observation and inference, of evidence and guesswork, of facts and fantasy, which makes the science of evolutionary storytelling so alluring, so exciting, and so fallible.
In this book I trace the history of
narrative phylogenetics—the science of evolutionary storytelling—from its
pre-evolutionary roots to the present day. I outline the conceptual shifts
involved in transforming a static view of nature into a dynamic view, where the
branching evolutionary relationships between taxa are understood to be the
products of the linear descent and divergence of evolving lineages. I discuss
the enduring challenges of what I call lineage thinking, which involves weaving
linear evolutionary narratives with branching evidence.
Several influential voices in the
professional, popular, and educational literatures have misconstrued lineage
thinking, and as a consequence have spread deeply misleading views that
continue to impact current thinking. Notable among these is the late Stephen
Jay Gould, whose confused views about the evolution of lineages I discuss in
detail. His failure to properly grasp the connection between the linear realm
of evolutionary descent and the branching realm of systematic relationships
between taxa led him to falsely condemn linear evolutionary imagery and
stories.
The same confusion has led other authors to
the spurious claim that Ernst Haeckel’s trees were thinly veiled scala naturae or ladders of life, not
Darwinian phylogenies. I take a detailed look at how Haeckel, the first
fulltime evolutionary storyteller, and other biologists and palaeontologists in
the late-nineteenth and early-twentieth centuries, reconstructed the evolution
of lineages with the evidence offered by fossils, embryos, and comparative
morphology. I show the degree to which evolutionary intuitions complement
fragmentary evidence in the spinning of evolutionary stories, and I analyse the
clash of intuitions and evidence in several persistent debates about the
evolution of animals. I also explore how and why certain evolutionary plot
lines—for instance evolution going from simple to complex morphologies—are so
attractive that evolutionists have allowed them to drive many different
stories.
Philosophical and methodological advances in systematic biology from the mid-twentieth century onwards have fundamentally transformed the direct, narrative approach to reconstructing the phylogenetic history of lineages. But although evolutionary storytelling has changed, it cannot be escaped. Evolutionary biologists are nature’s biographers. Like biographers we try to answer the who, what, where, how, and why questions in the lives of our central subjects, which are evolving lineages. Although we generate these answers today by applying sophisticated statistical methods to increasingly diverse and expanding datasets, we continue to integrate them into evolutionary narratives. It will always be thus.
Ancestors in Evolutionary Biology by Ronald A. Jenner
Ronald A. Jenner is Principal Researcher in the Department of Life Sciences at the Natural History Museum, London. His research focuses on animal phylogenetics, body plan evolution, the evolution of venoms, and conceptual issues in systematics. He has published extensively in the primary literature and co-authored Venom: The Secrets of Nature's Dea...
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