(Why) does evolution favour embryogenesis?

Trends Plant Sci.          online article

Complex multicellular organisms typically possess life cycles in which zygotes (formed by gamete fusion) and meiosis occur. The question arises whether embryo-like structures and associated developmental processes recurrently emerge because they are local optima of the evolutionary landscape. In order to understand which evolutionary principles govern complex multicellularity we need to analyse why and how similar processes evolve convergently – von Baer’s and Haeckel's phylotypic stage revisited in other phyla.