Phylogenetic approaches in comparative physiology

Abstract

SUMMARY Over the past two decades, comparative biological analyses have undergone profound changes with the incorporation of rigorous evolutionary perspectives and phylogenetic information. This change followed in large part from the realization that traditional methods of statistical analysis tacitly assumed independence of all observations, when in fact biological groups such as species are differentially related to each other according to their evolutionary history. New phylogenetically based analytical methods were then rapidly developed, incorporated into `the comparative method', and applied to many physiological, biochemical, morphological and behavioral investigations. We now review the rationale for including phylogenetic information in comparative studies and briefly discuss three methods for doing this(independent contrasts, generalized least-squares models, and Monte Carlo computer simulations). We discuss when and how to use phylogenetic information in comparative studies and provide several examples in which it has been helpful, or even crucial, to a comparative analysis. We also consider some difficulties with phylogenetically based statistical methods, and of comparative approaches in general, both practical and theoretical. It is our personal opinion that the incorporation of phylogeny information into comparative studies has been highly beneficial, not only because it can improve the reliability of statistical inferences, but also because it continually emphasizes the potential importance of past evolutionary history in determining current form and function.

Incorporating evolutionary insights to improve ecotoxicology for freshwater species

“…Blomberg K values can be >1, signaling a similarity in traits among closely related species that is greater than expected by Brownian motion evolution. Values <1 indicate less similarity among closely related species than expected by the null model of evolution, as seen in our K of 0.23 for the full 55‐species tree (Blomberg et al., 2003; Garland, Bennett, & Rezende, 2005). …”

Comparative and alternative approaches and novel animal models for aging research

“…In gerontology, comparative analyses have been included in the wide variety of approaches used to address mechanistic ideas about aging, including the "rate of living" theory (Rubner 1908;Pearl 1928) and its more recent incarnations, the free radical and oxidative stress theories (Harman 1956(Harman , 1972Beckman and Ames 1998;Muller et al 2007). Moreover, comparative data have been invaluable for testing hypotheses about evolutionary life history trade-offs relevant to aging processes (Stearns 1992;Garland et al 2005), as well as for identifying animal populations or species that are exceptionally long-or short-lived for their sizes, metabolic rates, or taxonomic groups, and that hence represent potentially useful models for aging studies (see, for example, Austad and Fischer 1991;Austad 1993Austad , 2001Holmes and Austad 1995;Miller et al 2002;Brunet-Rossinni and Austad 2004;Buffenstein 2005).…”

“…In general, however, gerontologists remain relatively unschooled in the potential inferential pitfalls associated with comparative studies of aging (Pagel 1992;Garland and Adolph 1994;Austad and Holmes 1999;Garland et al 2005;Ives et al 2007). Over the past 20 years, standards for the application of comparative methods in evolutionary biology have undergone aggressive revision, becoming much more analytically sophisticated (for a recent review, see Garland et al 2005).…”

“…Over the past 20 years, standards for the application of comparative methods in evolutionary biology have undergone aggressive revision, becoming much more analytically sophisticated (for a recent review, see Garland et al 2005). Among evolutionary biologists, the term "comparative analysis" now implies the application of rigorous and specialized inferential techniques designed to incorporate information about phylogeny (i.e., evolutionary relationships) into statistical tests of hypotheses about physiological or other functional differences between groups of organisms.…”

“…The most prominent of these, the comparative approach, consists of a collection of inferential and statistical methods that now constitute mainstream practice for zoologists and evolutionary biologists, but remain much less familiar to many biogerontologists, despite a long-standing interest in comparing aging of diverse animal taxa (Harvey and Pagel 1991;Pagel 1992;Garland and Adolph 1994;Garland et al 2005) (see also Furness and Speakman; Hulbert; Buffenstein et al; Gavrilova et al, this issue). In the broadest sense, this approach involves systematic comparison of aging-related phenomena among different strains, populations, species or other biologically meaningful groups.…”