NOTES-Chapter 21

NOTES-Chapter 21 - Chapter 21 & 22: Animal Development Four...

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Four Essential Developmental Processes o Cell proliferation and programmed cell death- cells divide by mitosis and cytokinesis. The timing location and amount of cell division and cell death is regulated o Cell movements or differential expansion- cells can move past one another within a block of animal cells, causing drastic shape changes within the embryo. Certain animal cells can break away form a block of cell and migrate to new locations. Plant cells can divide in certain planes and expand in specific directions, causing dramatic changes in shape. o Cell differentiation- undifferentiated cells specialize at specific times and places by a stepwise process during development. Cells that do not undergo differentiation are called stem cells in animals. Many plant cells are capable of de-differentiation. o Cell-cell interactions- embryonic cells grow, move, or differentiate in response to signals from other cells. Molecular development in the fruit fly, Drosphilia o The molecular development of drosphilia has been well studied for many years because it is a model organism-easy to rear in the lab in large quantities and possesses a relatively simple development plan. You can also kill quite a few to study without having to develop an elaborate animal care protocol. o The process of cleavage and gastrulation produces the body axis (dorsal-ventral and anterior posterior) and the embryonic tissues are arranged in layers which we call endoderm, mesoderm, and ectoderm. Next, the overall body plan takes shape with the development of organs, organ systems, and finally specialized cells which produce cell-specific proteins. The fundamental message of development is the fate of a cell depends
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This note was uploaded on 04/07/2011 for the course BIOL 104 taught by Professor Bray-speth during the Fall '11 term at Saint Louis.

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NOTES-Chapter 21 - Chapter 21 & 22: Animal Development Four...

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