Lab 1 - Animal Development Flashcards
creates new cells through mitosis
cell division
causes groups of cells to organize and move, to create an animal’s body shape
cell migration
causes cells to develop different morphological features for specialization toward specific tasks
cell differentiation
have very little yolk evenly distributed throughout the egg; undergoes holoblastic cleavage
Isolethical Eggs
the cleavage furrow extends completely through the egg and completely separates daughter cells
holoblastic cleavage
have a moderate amount of yolk concentrated at one end of the egg, referred to as the vegetal hemisphere, or pole; undergoes holoblastic cleavage but not as symmetrically
mesolecithal eggs
have a large amount of yolk, which occupies most of the cell volume, the embryo is confined to a small disc at the opposite pole of the cell, the animal pole; undergoes meroblastic cleavage
Telolecithal eggs
Because of the large, heavily concentrated yolk, cleavage is only partial, stopping at the border between the embryo and the yolk, and daughter cells remain connected to each other
meroblastic cleavage
have a large amount of yolk, but the embryo forms a thin layer around the outside of the large, central yolk mass
Centrolecithal eggs
when cleavage planes occur perpendicular or parallel to each other
radial cleavage
When cleavage planes occur at oblique angles
spiral cleavage
When cleavage planes are restricted to a dome of cytoplasm at one end of the yolk-laden cell
discoidal cleavage
the embryo is represented by a solid mass of tiny cells (blastomeres) that continue to divide at a furious pace
morula stage
solid mass of tiny cells
blastomeres
characterized by a migration of cells toward the periphery of the embryonic sphere, creating a hollow cavity deep within the spheroid of cells
blastula stage
The hollow, fluid-filled cavity within the blastula
blastocoel
Several hours after the formation of the blastula, a small depression begins to appear at one end of the embryo, and cells begin to organize, move, and start to create the geometry of the animal’s body, more and more cells stream inward, deepening the invagination
early gastrula stage
The opening to the outside of the embryo, marking the site of the inward migration of cells
blastopore
The hollow tube that is created by the arrangement of invaginated cells
gastrocoel/archenteron
By now, the individual cells are so small as to be indistinguishable from each other under normal magnification, At most, they appear as a flecking on the surface of the embryo, The archenteron has folded inward to the point of nearly connecting with the opposite end of the gastrula, and the shape of the gastrula has become markedly elongated, cell differentiation begins, and the primary tissue layers of the embryo start to form
late gastrula stage
morphogenesis and organogenesis have begun by this stage
bipinnaria larva
the development of the body shape
morphogenesis
organogenesis
the differentiation of organ tissues
one pole of the egg, appears lighter in coloration
vegetal pore
one pole of the egg, darker pole, represents the portion of the egg where the embryo will develop
animal pole