Why is it that many of the animal groups that appeared in the Cambrian period have no living relatives?
What will be an ideal response?
The Cambrian period was evidently one of great experimentation from an evolutionary perspective. A number of different body forms and ways of life evolved, many of which became extinct. Some others survived to eventually give rise to the animal lines in existence today.
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Prostaglandins are under neuroendocrine regulation
Indicate whether the statement is true or false.
How does the reabsorption of sodium affect the secretion of potassium?
A phospholipid is composed of
A) one fatty acid molecule linked to three glycerol molecules. B) one glycerol molecule linked to three phosphate groups. C) one fatty acid molecule linked to one glycerol molecule and two phosphate groups. D) one glycerol molecule linked to one phosphate group and two fatty acids.
In vertebrates, the family of myogenic regulatory factors (MRFs) plays a major role in muscle development. This family consists of four related genes that have distinct but overlapping functions. This gene family is represented by only a single gene in Drosophila, called nautilus. You want to know whether nautilus plays a role like all of the MRFs put together, or more like one in particular. What is a quick and easy way to begin to address this question?
A. Use a DNA microarray to compare gene activation patterns between nautilus and the MRFs. B. Compare the proteome of a cell expressing nautilus to the those of cells expressing each of the MRFs in turn. C. Generate four transgenic Drosophila strains that express the MRFs in a mutant nautilus background. D. Compare the DNA and protein sequences of all the genes to determine if nautilus is more similar to one MRF than another.