  Inspired by recent experiments that highlight the role of nematic defects in
the morphogenesis of epithelial tissues, we develop a minimal framework to
study the dynamics of an active curved surface driven by its nematic texture.
Allowing the surface to evolve via relaxational dynamics leads to a theory
linking nematic defect dynamics, cellular division rates and Gaussian
curvature. Regions of large positive (negative) curvature and positive
(negative) growth are colocalized with the presence of positive (negative)
defects. Applying this framework to the dynamics of cultured murine neural
progenitor cells (NPCs) in an ex-vivo setting, we find that cells accumulate at
positive defects and are depleted at negative defects. In contrast, applying
this to the dynamics of a basal marine invertebrate \emph{Hydra} in an in-vivo
setting, we show that activity stabilizes a bound $+1$ defect state by creating
an incipient tentacle, while a bound $+1$ defect state surrounded by two $-1/2$
defects can create a stationary ring configuration of tentacles, consistent
with observations.
