Systematics and the Origin of Species: On Ernst Mayr's 100th Anniversary

by Jody Hey

Biology is a science of three dimensions. The first is the study of each species across all levels of biological organization, molecule to cell to organism to population to ecosystem. The second dimension is the diversity of all species in the biosphere. The third dimension is the history of each species in turn, comprising both its genetic evolution and the environmental change that drove the evolution.

The triumph of molecular and cellular biology has been the documentation of one of the two overarching principles of biology: that all living phenomena are obedient to the laws of physics and chemistry. The other overarching principle of biology is that all living phenomena originated and evolved by natural selection. That, in turn, has been the triumph of organismic and evolutionary biology.

The proportionate shortfall of the disciplines can be expressed in practical terms as follows. A large part of the success of molecular and cellular biology is due to their relevance to medicine. In public perception and support, they are virtually married to medicine. Hence, molecular and cellular biology are rich not so much because they have been successful; rather, they are successful because they have been rich. What needs to be appreciated for the future of organismic and evolutionary biology in practical terms is that where molecular and cellular biology are vital to personal health, organismic and evolutionary biology are vital to environmental health, and thence also to personal health.

Are speciation genes “ordinary” genes that have normal functions within species? If so, do speciation genes fall into one or at least a few functional classes? Are substitutions in speciation genes concentrated in coding or regulatory sequences? And do speciation genes diverge by natural selection or genetic drift?