Finding the way in phenotypic space: the origin and maintenance of constraints on organismal form.
BACKGROUND
One of the all-time questions in evolutionary biology regards the evolution of organismal shapes, and in particular why certain forms appear repeatedly in the history of life, others only seldom and still others not at all. Recent research in this field has deployed the conceptual framework of constraints and natural selection as measured by quantitative genetic methods.


METHODS
In this paper I argue that quantitative genetics can by necessity only provide us with useful statistical summaries that may lead researchers to formulate testable causal hypotheses, but that any inferential attempt beyond this is unreasonable. Instead, I suggest that thinking in terms of coordinates in phenotypic spaces, and approaching the problem using a variety of empirical methods (seeking a consilience of evidence), is more likely to lead to solid inferences regarding the causal basis of the historical patterns that make up most of the data available on phenotypic evolution.
Pigliucci
Massimo
M
Department of Ecology and Evolution, Stony Brook University, 650 Life Sciences Building, Stony Brook, NY 11794, USA. pigliucci@genotypebyenvironment.org
D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D010641:Phenotype; D063245:Plant Development; D010944:Plants / Q000235:genetics*