Key concepts

The “traditional phenotype” of an individual plant or population results from the interactions of genes in an organism and the environment to affect traits such as plant architecture and leaf shape (see illustration). Other traditional phenotypes of great interest include resistance to disease, drought tolerance and seed production. Such traits are often the focus of breeding efforts because of their economic value.

The “community phenotype” is the expression of a trait at a level higher than the individual or the population. These phenotypes result from the genetics-based interactions of two or more species and the environment to affect community traits such as species richness, abundance, and composition. For example, the genetics-based interactions of beavers and cottonwood trees define a much larger community of insects (see illustration). The effects of genes at levels higher than the population. These phenotypes result from interspecific indirect genetic effects, which can be summarized as a univariate trait.

The “ecosystem phenotype” also results from the genetics-based interactions of two or more species and the environment to affect ecosystem traits such as decomposition and nutrient cycling. For example, the genetics-based production of condensed tannins and lignin affect the microbial processing of leaf litter, which affects the cycling of essential nutrients such as nitrogen. In turn, the cycling of nitrogen affects most if not all other organisms in the ecosystem (see illustration).

This hierarchy of phenotypes from the finest level of the traditional phenotype, to the higher levels of the community and ecosystem phenotypes have been quantified for an individual plants. For example, different genotypes of cottonwoods differ in important traditional phenotypes, which in turn results in each of these genotypes supporting differing insect communities and having different ecosystem traits of decomposition and nutrient cycling. Because these phenotypes are passed from one generation to the next, they are heritable, subject to natural selection, and they can evolve.