Evo-Devo is the other name for "Evolutionary-Developmental Biology", which is quite a recent field of study in evolutionary biological sciences that aims at comparing developmental processes of different organisms, right from their embryonic stage, in order to study their rich evolutionary patterns.
Evo-Devo studies focus on how different species, having a presumed common ancestry, acquired diverse features in the course of their evolutionary development. The research methodologies of Evo-Devo scientists are not dependent on classical approaches, but rather, they encompass modern genetic techniques.
The foundations of Evo-Devo studies lie in Theory of Common Ancestry and Natural Selection postulated by Charles Darwin. Studying embryos of different species, which appear nearly indistinguishable to even the best of Embryologists, Evo-Devo scientists try to investigate the links between different organisms. What exactly should or shouldn't be included in Evo-Devo is still a debate for many, but for sure, it is very challenging and yet equally interesting.