Observing embryos of different species , he described how animals born in eggs ( oviparously ) and by live birth ( viviparously ) developed differently .
Aristotle was the earliest person in recorded history to study embryos .
Observing embryos of different species , Aristotle described how animals born in eggs ( oviparously ) and by live birth ( viviparously ) developed differently .
Aristotle was the earliest person in recorded history to study embryos .