Anole Annals

httpv://www.youtube.com/watch?v=r33UMVk1o5s&feature=email

As a scientist in life sciences, I have always tried to highlight the existence of laws. It seems to me that all science should be predictive. Once we are interested in locomotion, the first idea that comes to mind is the following: are there any laws of locomotion that transcend forms, species? Is it possible to predict locomotion of any species to the knowledge of environmental constraints it faces (Legreneur et al., 2012)?

I am not a herpetologist. Over 15 years I have worked on humans, and especially high-level athletes and the elderly. I demonstrated in humans that the trajectory of any point controlled by the central nervous system was still as linear as possible. This point is either the fingertip during a pointing or grasping task, or the body center of mass during locomotion, e.g. during the takeoff phase of a jump. Since most joints move in rotation, and that the controlled point displaces through a linear path, it is necessary to dephase the rotating joints to transform the rotation kinematic energy into linear energy. Finally, for transmiting force from the body to the substrate, for example from the hip to the ground during the jump, the joints move in a proximal-to-distal manner, i.e. the extension of the hip precedes the ones of the knee and the ankle.

To demonstrate that these laws observed in humans were applicable to all terrestrial tetrapods, I am interested in two phylogenetically very distant arboreal jumpers, i.e. a prosimian, Microcebus murinus, and a squamate, Anolis sp. I reproduced with these two species the same experiments that I conducted on humans, i.e. leap up to maximum and submaximal heights. Thus I demonstrate that the coordination observed during take-off in maximal leaping were identical in humans, Microcebus and Anolis (Legreneur et al., 2010; Legreneur et al., 2011; Legreneur et al., 2012).

Read More

The University of Chicago Press has recently published another outstanding new book for comparative biologists.  Charles Nunn‘s The Comparative Approach in Evolutionary Anthropology and Biology provides insightful reviews of methods for ancestral character reconstruction, phylogenetic tests for character correlation, phylogenetic diversification analyses, and many other topics.  Nunn’s book seems well-suited to a broad range of readers.  It seems tractable for novices (the second chapter explains what a phylogenetic tree is), and those with math anxiety won’t be deterred by dense discussions of mathematical or computational algorithms.  At the same time, seasoned comparative biologists will likely appreciated Nunn’s fairly comprehensive coverage of alternative methods and their relative strengths and weaknesses.  Although most of Nunn’s examples are from anthropology, the general lessons in this book are likely to be of interest to many anole biologists and the examples from anthropology are often insightful and thought provoking.  To top it all off, the book is accompanied by really nice webpage called AnthroTree that features tutorials and worked examples.

Springer recently published a new and dramatically expanded version of Pardis’s book Analysis of Phylogenetics and Evolution with R.  This book is a great way to teach yourself some of the amazing techniques available for phylogeneticists and comparative biologists via the R statistical computing environment. With 386 pages, the new edition is nearly twice as large as the previous version (211 pages).  Countless new methods are covered, and many problems with the previous edition are remedied.  In spite of the expansion and improvements, the sticker price is actually lower on the new edition ($65) than it was on the old edition ($75).  You can pick up a copy for around $50 at places like Amazon.com.  This book should be considered required reading for anyone doing modern phylogenetic and comparative analyses.  If you need anoles to inspire an interest in learning R, I’ll be posting shortly on some R tutorials that use anoles as case studies.