Embryonic Development

The developing embryo does not receive nourishment from mother's body in oviparous reproduction. 

Parthenogenesis is the development of an embryo from an unfertilised egg or if a spermatozoan does penetrate the egg, there is no union of male and female pronuclei. It is found in many plants (dandelions and hawk weeds) and animals (aphids and honey bees).

Cellular differentiation is the process by which a cell changes from one cell type to another. Usually, this is because a less specialised type becomes a more specialised type, such as during cell growth.

When the somatic cells are cultured and the culture is made stationary, each cell starts differentiating into an independent embryo showing all the stages of embryo development. These embryos are called embryoids, which can give rise to a complete plant.

Telolecithal also known as macrolecithal, refers to the uneven distribution of yolk in the cytoplasm of ovums found in birds, reptiles, fish, and monotremes. Mesolecithal eggs have comparatively more yolk than the microlecithal eggs. The yolk is concentrated in one part of the egg (the vegetal pole), with the cell nucleus and most of the cytoplasm in the other (the animal pole).

In all bilaterian animals, the mesoderm is one of the three primary germ layers in the very early embryo. The other two layers are the ectoderm (outside layer) and endoderm (inside layer), with the mesoderm as the middle layer between them.The mesoderm forms mesenchyme (connective tissue), mesothelium, non-epithelial blood cells and coelomocytes. Mesothelium lines coeloms; forms the muscles in a process known as myogenesis, septa (cross-wise partitions) and mesenteries (length-wise partitions); and forms part of the gonads (the rest being the gametes)

Fact

Fertilisation is the first phase.

ectodem

Sorghum, like other grasses (Poaceae), has a single ovule at the base of the ovary, which is characteristic of basal placentation.

The appendix is a blind-ended tube connected to the cecum (or caecum), from which it develops embryologically. The cecum is a pouchlike structure of the colon. The appendix is located near the junction of the small intestine and the large intestine.

Embryo development is meroblastic in selliginella.

Epithelial tissues are derived from all of the embryological germ layers from ectoderm (e.g., the epidermis); from endoderm (e.g., the lining of the gastrointestinal tract); from mesoderm (e.g., the inner linings of body cavities).

Epithelium of the gut originates from the endoderm.

-