Inheritance is where physiology meets evolution

Abstract

Physiology and evolutionary biology have developed as two separated disciplines, a separation that mirrored the hypothesis that the physiological and evolutionary processes could be decoupled. We argue that non-genetic inheritance shatters the frontier between physiology and evolution, and leads to the coupling of physiological and evolutionary processes to a point where there exists a continuum between accommodation by phenotypic plasticity and adaptation by natural selection. This approach is also profoundly affecting the definition of the concept of phenotypic plasticity, which should now be envisaged as a multi-scale concept. We further suggest that inclusive inheritance provides a quantitative way to help bridging infra-individual (i.e. physiology) with supra-individual (i.e. evolution) approaches, in a way that should help building the long sough inclusive evolutionary synthesis.

Figure 1. Scopes of physiology and evolution on the scales of life organization

Physiology regroups phenomena taking place within the life cycle of a single organism, while evolution regroups populational phenomena of intergenerational change. The circle on the left side, as well as every circle on the right side represent the full life cycle of a single individual. Different lines of circles stand for different generations.

Figure 2. From phenotypic plasticity to inclusive inheritance

Non-genetic inheritance is affecting the classic vision of phenotypic plasticity. The Y axis quantifies any phenotypic trait, including morphological, physiological and behavioural, including language. The X axis depicts the environment in all its dimensions, including climate, food, safety, as well as competition and the social milieu (social context, potential mates, culture, etc.). See text.