What's in a (Quantifiable) Trait? Of Evolution, Evolvability, and Human Variation

November 16, 2017 by Kristen Savell in Evolution, Human evolution, Quantitative genetics, Variation

One of the challenges of understanding evolution is determining what makes a trait meaningful for a research question. Quantitative genetics literature in general gives limited guidance on this point, as any quantitative trait simply needs to be a quantifiable quality of an organism, and not a discrete class; it needs to have a continuous distribution and be measurable on a scale. For a trait to be applicable to evolutionary quantitative inquiry, it needs to be heritable. What often is missed is that the degree to which such traits are able respond to selective pressures is itself an evolvable trait, a quality we term "evolvability." Since we have evidence that the correlations between measures of body form have strongly affected human evolution across ecogeographic regions, I decided to see if the measures of evolvability between these human populations would notably differ.

Monkeying around with Morphospaces

October 31, 2017 by Samuel Williams in Evolution, Ornstein-Uhlenbeck, Phylogenetic modeling, Quantitative genetics

In my last post, I introduced the concept of a morphospace – the bounded range of possible shape variation that exists for a given trait in either one population of organisms or a trait shared by several related populations of organisms. Morphospaces are crucial to understanding morphological (shape) variation in two important ways: 1) determining how past evolutionary forces have acted to produce a particular morphology, and 2) predicting how current and future evolutionary forces will alter that morphology over time. In this post, I write about studying the first concept in traits that might capture facial shape change in response to climatic variation among macaques. What I found, however, was surprising.

What’s in an Age? [Guest post from Dr. Alice Gooding, Kennesaw State University]

September 28, 2017 by Alice Gooding in Biomechanics, Human evolution, Evolutionary Medicine, Evolution, Guest post

Are we really doomed to mechanical and material breakdowns in our skeletons shortly after we reach adulthood? It is true that bone loss with age in humans is nearly universal. It has been documented worldwide in both living and past populations, as well as non-human primates. And though bone loss may begin after bones fuse, it accelerates during mid-life (after age 40) and continues after mid-life in humans. Increased bone loss is concurrent with an increased risk of fracture, decreased mobility, and even in industrialized societies, increased mortality. Why do humans live long past the years when bone loss begins?

Making Medical Practitioners Biologists and Not Mechanics: Lessons from ISEMPH 2017

September 04, 2017 by Benjamin Auerbach in Academia, Pedagogy, Science Communication, Scientific meetings

A long-standing concern of the International Society for Evolution, Medicine, and Public Health and its membership is that more than cursory education in the most basic evolutionary theory, or how scientific inquiry is conducted, is lacking from many medical curricula. This is alarming when we consider that medicine is a form of applied biology. As evolutionary theory is the principal principle that unites all biology (much as physics underlies all engineering), learning a form of applied biology should logically begin with an education in evolution. Furthermore, scientific literacy, and the ability to tell well-executed science from poorly executed research, is essential when evaluating a burgeoning literature ranging from experimental therapies to evolving pathogens.