The December issue of The Quarterly Review of Biology is now available. The issue features articles on the nature of individual organisms, evolution observed in the lab, play behavior across animal species, and a criticism of intelligent design creationism. Abstracts are available at http://www.journals.uchicago.edu/toc/qrb/current.
What is an Individual?
For organisms like fish, mice, and people, it's not hard to distinguish between individuals. However, for colonial creatures like corals and anemones, and for organisms like slime molds and bacteria, the line separating individual and group is blurred. According to Henri J. Folse III and Joan Roughgarden of Stanford University, the traditional method of defining an individual organism"one genome in one body"should be discarded. Instead, they propose defining individuals from an evolutionary perspective. In their view, the hallmarks of an individual organism are that its component parts have aligned evolutionary fitness interests; that its parts exhibit division of labor between reproductive and non-reproductive tasks; and that its parts form a functional adaptive organization. Under this rubric, a colony of eusocial insects such as honeybees would qualify as an individual organism, despite genetic differences within the colony. Most colonies of modular organisms such as corals would not qualify despite genetic similarity within the colony.
Henri J. Folse III and Joan Roughgarden, "What is an Individual Organism? A Multilevel Selection Perspective"
Experimental Evolution: Losing Function is Often a Good Thing
For 40 years, scientists have used quickly reproducing bacteria and viruses to watch evolution in action in the laboratory. During that time, scientists have reported numerous genetic mutations that increase the evolutionary fitness of these experimental bacteria. In reviewing four decades of this research, biochemist Michael J. Behe (Lehigh University) points out that at the molecular level, these adaptive mutations come in three varieties: those that result in a loss of function (for example, a mutation causes a gene to stop making a protein), a modification of function, or a gain of a new function. Behe points out that very few adaptive mutations found in the lab thus far involve a gain of function. Instead, the vast majority are loss-of-function mutations or modifications leading to diminished function. Behe refers to the expectation that most adaptive evolution involves lost or diminished function as "The First Rule of Adaptive Evolution."
Michael J. Behe, "Experimental Evolution, Loss-of-Function Mutations, and 'The First Rule of Adaptive Evolution'"
State of Play
Despite its ubiquity across animal species, play behavior has received comparatively little attention from biologists. However, according to Kerrie Lewis Graham (Texas State University, San Marcos) and Gordon M. Burghardt (University of Tennessee), there has been a recent surge in research on play. "Once considered to be useless, frivolous, or only for the direct practice of adult behavior patterns, today we recognize that play is a heterogeneous category of behavior with diverse causal mechanisms, evolutionary histories, developmental trajectories, and experiential components," the researchers write.
Kerrie Lewis Graham and Gordon M. Burghardt, "Current Perspectives on the Biological Study of Play: Signs of Progress"
The Incoherence of Irreducible Complexity
Advocates of intelligent design creationism often tout the concept of irreducible complexity (IC) as a withering critique of Darwinian evolution. But Maarten Boudry, Stefaan Blancke, and Johan Braeckman, (Ghent University, Belgium) argue that IC as defined by its most vocal proponent, Michael Behe, is a conveniently vague concept. IC advocates use the grey areas in the concept's definition to evade criticism from evolutionary biologists. "Indeed, in the past two decades the concept of IC seems to have found receptive mental soil among anti-evolutionists," the authors write. "An analysis of the convenient conceptual equivocations inherent in IC, as well as of the rhetorical strategies with which IC has been presented, helps us to understand this remarkable fertility."
Maarten Boudry, Stefaan Blancke, and Johan Braeckman, "Irreducible Incoherence and Intelligent Design: A Look into the Conceptual Toolbox of a Pseudoscience"
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