Ecological Developmental Biology

Abstract

Ecological developmental biology is the science that studies the interactions between developing organisms and their environmental contexts. It studies development in the ‘real world’ of predators, competitors, symbionts, toxic compounds, temperature changes and nutritional differences. The environment plays a substantial role in development, and in many instances, normal development cannot occur without environmental signalling. Symbionts, for instance are needed in many organisms for the development of particular organs. Environmental agents can elicit epigenetic changes in gene expression that can change an organism's phenotype. In many instances, however, substances in the environment of developing organisms can act detrimentally, causing birth defects and predisposing the organism to diseases in adulthood. Epigenetics has recently provided startling insights into how environmental agents experienced during embryonic development can predispose one to cancer, obesity, hypertension and diabetes later in life. Key Concepts: The environment plays critical roles during normal development. The genome encodes a repertoire of possible phenotypes. Environment often selects which of those genes will become active and which phenotypes will become expressed. Reaction norms are phenotypes that quantitatively respond to environmental conditions, such that the phenotype reflects small differences in the environmental conditions. Polyphenisms represent ‘either/or’ phenotypes wherein one set of conditions elicits one phenotype, while another set of conditions elicits another phenotype. Organisms usually develop in symbiotic relationships with other organisms; and signals from the symbionts are often critical for normal development. Teratogens (such as ethanol) are compounds that can cause birth defects by disrupting normal development. Endocrine disruptors are compounds in the environment that can disrupt normal development by changing gene expression in ways that are not seen phenotypically for years after birth. Ecological developmental biology proposes new mechanisms through which evolution can occur. These include epialleles (inherited patterns of chromatin alterations giving inherited variants of gene expression patterns), plasticity‐driven adaptation and symbiont‐mediated variation.