Alex Kalinka and I (in that order) have written an opinion piece for Trends in Ecology and Evolution where we put forward a new perspective on the evolution of animal life-cycle inspired by the recent studies of the developmental hourglass model. The early development is plastic; the egg is an evolutionary innovation and an extension of the mother reflecting its ecological circumstance. The oldest, foundational stage of development is the phylotypic period that recapitulates the adult stage of a primitive multicellular ancestor (go Haeckel). Aristotle was asking the wrong question, neither chicken nor the egg were the first, it was the pharyngula.

Consider this food for thought. Maybe we could start a polemic below, but for that someone would have to actually use this site…

PAvel