The living world that we humans are a part of was shaped over billions of years of evolution. As a result of natural selection, organisms are adapted for a particular set of environmental circumstances: Polar bears are designed to live in a cold, arctic habitat and eat a meat-heavy diet; cows function best when they have access to green, open pastures covered in grass; tigers are morphologically sculpted to eat primarily meat and live in a hot, sunny environment; and so forth.
Evolution has equipped biological systems with adaptive capabilities (e.g., epigenetic regulatory mechanisms), which allow for developmental/phenotypic adjustment in response to environmental change; however, there’s a limit to this flexibility. Organisms that are subjected to conditions that differ markedly from the conditions they are evolutionary conditioned for express a suboptimal phenotype and suffer health wise. Their Darwinian fitness may also be affected.
Why it’s important to know about evolutionary mismatch theory
The evolutionary mismatch concept is particularly relevant in the times in which we live, seeing as the environment of the Earth has changed dramatically over the most recent millennia, in large part because of human activities. As a result, many organisms, including most humans, today live in an environment that is mismatched with their biology.
A large body of research shows that evolutionary mismatches underlie a staggering number of diseases and health problems (1, 2, 3, 4, 5, 6). Most health disorders, ranging from obesity to acne vulgaris to heart disease, can be understood on the basis of evolutionary mismatch theory. By invoking such theory, one not only gets to appreciate why disease exists, but also how it can be effectively prevented and treated.
Depictions of the evolutionary mismatch concept
The infographics below depict the relationship between environmental change, evolutionary mismatch, and organismal health.