Cnidaria develop from two layers of tissue, the ectoderm and the endoderm, and are thus termed gastrula.
12.
The term refers to the order of organization of cells in the gastrula leading to development of the coelom.
13.
It includes a blastula, gastrula and a four armed echinopluteus stage that forms an important part of the zooplankton.
14.
Briefly, embryonic developments have four stages : the morula stage, the bastula stage, the gastrula stage, and the neurula stage.
15.
It first invaginates to form a gastrula with a digestive chamber, and two separate germ layers an external ectoderm and an internal endoderm.
16.
The filopodia thin fibers formed by the mesenchyme cells found in a late gastrula contract to drag the tip of the archenteron across the blastocoel.
17.
The parts that are autotomised or the buds may develop directly into fully formed larvae or may develop through a gastrula or even a blastula stage.
18.
The Cerberus gene encodes a polypeptide that is 270 amino acids in length and is expressed in the anterior domain of a gastrula in the endoderm layer.
19.
The epiblast has now differentiated into the three germ layers of the embryo, so that the bilaminar disc is now a trilaminar disc, the gastrula.
20.
In mammals, the primitive streak and other surrounding tissues produce the morphogenic compounds Wnts, Nodal and retinoic acid to establish the posterior region during late gastrula.
