• It is the field of biology that deals with study of
development of an organism from its earlier
beginning to its maturity.
• Dynamic process.
• Two ways: 1)sexually and 2)asexually.
• Two distinct phases : 1)Embryonic period and
2) Post embryonic period.
• Embryology :Development in embryonic period.
• A phase early in the development of most animal embryos,
during which the morphology of the embryo is dramatically
restructured by cell migration.
• These cellular movements are called morphogenetic movements.
• Two types: 1) Epiboly and 2) Emboly
• Emboly –
• Invagination is the local inward movement of cells from a cavity.
• Involution is similar, but more dramatic. It is an inward expansion
of epithelial cells around an edge such as the blastpore.
• Ingression is the movement of individual cells from an epithelium
into an embryonic cavity.
• The three layers produced by gastrulation are
called embryonic germ layers
• The ectoderm
• Forms the outer layer of the gastrula
• The endoderm
• Lines the embryonic digestive tract
• The mesoderm
• Partly fills the space between the endoderm
• Differentiation of primary germ layers into tissues
• Organogenesis is the period of animal
development during which the embryo is
becoming a fully functional organism capable of
independent survival .
• It is the process by which specific organs and
structures are formed, and involves both cell
movements and cell differentiation.