The cleavage pattern in the Avain species is Mesolecithal, displaced radial cleavage Isolecithal, rotational cleavage Meroblastic, discoidal cleavage Centrolecital, superficial cleavage In bird eggs, the first division occurs Equitorial Centrally Laterally Posteriorally In the bird eggs the early cleavage cells maintain contact with Each other Yolk The deeper marginal zone cells Both the yolk and each other The blastopore is unique to all: Protosomes Deuterosomes Evidence of a Deep homology between Vertebrates and invertebrates None of these responses Solution 34. Cleavage pattern in avian species is Meroblastic discoidal cleavage. 35. In bird egg the first division occurs centrally 36.In the bird egg the early cleavage cells maintain contact with both each other and the yolk. 37..