Energetics and evolutionary fitness

I pass on the first paragraph of a perspectives piece in PNAS by Vermeij et al. that gives their message more thoroughly than the paper's abstract. Motivated readers can obtain a copy of the whole essay from me. 

Organisms acquire energy and material resources and convert these to activity and living biomass (1). The role of energy as currency (or power, energy per unit time) in evolution has long been recognized (2–6), but how energy acquisition and allocation affect evolution remains the subject of disagreement. In this perspective, we show how different assumptions about whether life operates in a dynamic steady state or whether it has expanded over the course of its history lead to contrasting predictions about adaptation, natural selection, and “fitness.” We conclude that models based on steady-state assumptions do not adequately account for observed patterns of adaptive change and evolutionary trends of increasing power and species richness over long periods of time, whereas models based on individual and collective power, which incorporate activity and the effects of organisms on their surroundings as components of survival and reproduction, reflect the history of adaptation more faithfully. The issue is important because energy (the currency of life) and power (energy acquired and expended per unit time) offer a unified framework for interpreting the course and outcomes of evolution. Models based on assumptions that reflect observed patterns should be more predictive than zero-sum models not only in the realm of evolution but also in ecology and economics.

How complex brains and cognition first arose

I have received a draft of an upcoming paper in Behavioral and Brain Sciences by Coombs and Trestman titled "A Multi-Trait Embodied Framework for the Evolution of Brains and Cognition across Animal Phyla "  It has a nice graphic indicating different brain regions whose functionalities are common to humans and phylogenetically different animals with complex brains  (crows, octopuses and honeybees).  Motivated readers can obtain a PDF of the article from me.  Here is the abstract :

Among non-human animals, crows, octopuses and honeybees are well-known for their complex brains and cognitive abilities. Widening the lens from the idiosyncratic abilities of exemplars like these to those of animals across the phylogenetic spectrum begins to reveal the ancient evolutionary process by which complex brains and cognition first arose in different lineages. The distribution of 35 phenotypic traits in 17 metazoan lineages reveals that brain and cognitive complexity in only three lineages (vertebrates, cephalopod mollusks, and euarthropods) can be attributed to the pivotal role played by body, sensory, brain and motor traits in active visual sensing and visuomotor skills. Together, these pivotal traits enabled animals to transition from largely reactive to more proactive behaviors, and from slow and two-dimensional motion to more rapid and complex three-dimensional motion. Among pivotal traits, high-resolution eyes and laminated visual regions of the brain stand out because they increased the processing demands on and the computational power of the brain by several orders of magnitude. The independent acquisition of pivotal traits in cognitively complex (CC) lineages can be explained as the completion of several multi-trait transitions over the course of evolutionary history, each resulting in an increasing level of complexity that arises from a distinct combination of traits. Whereas combined pivotal traits represent the highest level of complexity in CC lineages, combined traits at lower levels characterize many non-CC lineages, suggesting that certain body, sensory and brain traits may have been linked (the trait-linkage hypothesis) during the evolution of both CC and non-CC lineages.