"is an overarching theoretical perspective on biological development, heredity, and evolution.^[1] It emphasizes the shared contributions of genes, environment, and epigenetic factors on developmental processes. DST, unlike conventional scientific theories, is not directly used to help make predictions for testing experimental results; instead, it is seen as a collection of philosophical, psychological, and scientific models of development and evolution. As a whole, these models argue the inadequacy of the modern evolutionary synthesis on the roles of genes and natural selection as the principle explanation of living structures. Developmental systems theory embraces a large range of positions that expand biological explanations of organismal development and hold modern evolutionary theory as a misconception of the nature of living processes.

All versions of developmental systems theory espouse the view that:

• All

  biological processes

  (including both evolution and development) operate by continually assembling new structures.

• Each such

  structure

  transcends the structures from which it arose and has its own systematic characteristics, information, functions and laws.

• Conversely, each such structure is ultimately

  irreducible

  to any lower (or higher) level of structure, and can be described and explained only on its own terms.

• Furthermore, the major processes through which life

  as a whole operates, including

  evolution

  , heredity and the development of particular organisms, can only be accounted for by incorporating many more layers of structure and process than the conventional concepts of ‘

  gene

  ’ and ‘

  environment

  ’ normally allow for.

In other words, although it does not claim that all structures are equal, development systems theory is fundamentally opposed to reductionism of all kinds.