Futuyma and colleagues (1995 ) demonstrated that host shifts by the herbivorous leaf beetles of the genus Ophraella in feeding on members of the sunflower family are constrained by what?
What will be an ideal response?
a lack of genetic diversity that would enable the beetles to detect and detoxify chemical defenses produced by nonhost plants
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The SOS regulatory system is activated by
A) the activity of DNA polymerase IV. B) DNA damage. C) transcription of LexA. D) repression of RecA.
Select the potential problems with using current dispersal barriers (for example, a mountain range) to delineate biogeographical regions. Check all that apply.
A. A barrier for one group of organisms may not be a barrier for another group of organisms. B. Global climate change may change the distribution of taxa and the size and/or location of some of the dispersal barriers. C. The world's biota correspond more closely to political boundaries. D. Human conflicts lead to ever-changing political boundaries. E. Distantly related organisms with similar appearance and habits may exist on either side of a dispersal barrier.
A microbiologist must culture a patient's feces for intestinal pathogens. Which of the following would likely be present in selective media for analyzing this fecal specimen?
A. thioglycolic acid B. sheep red blood cells C. bile salts D. peptone E. NaCl
Which statement about the B cells' abilities to produce antibodies is most accurate?
A) There are no B cells until an antigen is encountered. B) Most B cells are capable of producing any kind of antibody. C) B cells wait to encounter an antigen and then copy it. D) There may be 100 million different B-cells, each producing a different antibody. E) B cells don't produce antibodies until they develop in the thymus.