#Question id: 18701
#Unit 13. Methods in Biology
#Question id: 4713
#Unit 11. Evolution and Behavior
A farmer uses triazine herbicide to control pigweed in his field. For the first few years, the triazine works well and almost all the pigweed dies; but after several years, the farmer sees more and more pigweed. Which of these statements explains why the pigweed reappeared?
#Question id: 12376
#Unit 10. Ecological Principles
#Question id: 13131
#Unit 10. Ecological Principles
Biologists performed an experiment with flies to examine the effects of population size on the maintenance of genetic variation and on egg-to-adult survival. From a large source population, they randomly assigned eggs to three experimental populations of size N, equal to 20, 60, and0100. For later generations, they collected N eggs from each population and moved them into identical vials that co0ntained f2re0sh me4d0ium. Th6e0y coun8te0d the number of adult flies that emerged and used tissue samples from the adults for genetic analyses. Genetic variation was measured by scoring alleles at several polymorphic loci and expressed as the average number of alleles at those loci. The results are summarized in Figure 1 and Figure 2 below.
The numbers of adult flies that emerged from the three populations in the first generation are closest to which of the following?
#Question id: 23861
#Unit 13. Methods in Biology