01:119:116 Lecture Notes - Lecture 5: Blastomere, Symmetry In Biology, Blastocoel
15 Mar 2016
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Differentiated cells: most have differentiated tissues. Act as functional unit: higher forms. Perform function: muscle and nerve tissue. Diploid stage dominant in life cycle: meiosis, fertilization. Produces a gastrula that has different layers of embryonic tissues: fig 32. 2, gastrula. Endoderm inner layer of embryonic tissue. Some animals: develop directly into adults. Other animals: have at least 1 larval stage. Different foods and habitats than adult stage. Development regulated by gene expression: homeobox genes. Code for proteins that regulate expression of developmental genes: ex. Control expression of many genes that influence morphology: fig 32. 3. A set of morphological and developmental traits: mechanism of comparison, represent key steps in animal evolution. Differentiation of cells tissues and organs: all animals have specialized cells. But not all have clearly defined tissues and organs: 1st major step. Do not have clearly defined tissues and organs. Do have clearly defined tissues and organs: symmetry. Arrangement of body structures in relation to axis of body.
