Evolutionary developmental biology

Evolutionary developmental biology (also known as evo-devo) is a field of biology that compares the developmental processes of different organisms to determine the ancestral relationship between them, and to discover how developmental processes evolved.

Overview
The developmental approach to evolution was excluded from the modern synthesis, as it was thought that population genetics could explain evolution, whilst morphology and development were seen to play little role in modern evolutionary theory. This, however, has in recent years been challenged, as research has shown how developmental processes are important in evolution.

According to evo-devo scientists, population genetics and the developmental genetics accounts are both required to explain evolution. Some evo-devo researchers have pointed out limitations of classic neo-Darwinism, see themselves as extending and enhancing the modern synthesis, and have also challenged certain tenets of neo-Darwinism and taken evolutionary theory beyond the boundaries of the modern synthesis. Thus the field of evo-devo has been incorporated into the extended evolutionary synthesis.

Developmental biology is one of the fastest growing fields in biology, creating a framework that integrates molecular biology, physiology, cell biology, anatomy, neurobiology, immunology, ecology, and evolutionary biology.

A classic example of evo-devo would be treatise on the comparative anatomy of the embryos of animal species. While Haeckel exaggerated some of the data, he did more or less accurately portray the developmental similarities of the embryos of related taxa. Haeckel noted that each of the embryos of the vertebrates, for instance, developed a pharyngeal gill slits, and a tail. Funnily enough, human embryos reabsorb their tail later on in development (because we're apes).

Debunking creationism
According to evo-devo scientists, by leaving developmental biology out of the neo-Darwinian synthesis, it has left evolutionary biology open to attacks by creationists. According to creationists, population genetics cannot explain the origin of complex structures such as the eye, so evolution must be false. Creationists have questioned how complicated structures have emerged by a collection of random mutations.

In response to these creationist claims, Scott F. Gilbert has written: