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, no matter how often he applies triazine. Which of these actions is most likely to solve the farmer's problem?
A) adding triazine more often to his fields B) trying a different herbicide C) applying the triazine to the soil and roots instead of spraying it over the leaves D) increasing the amount of triazine he puts on his fields
Which of the following statements describes a vestigial trait?
A) Whales and dolphins must breathe air even though they spend their entire lives in the water. B) Penguins are flightless birds with wings that are specialized for swimming. C) Humans still have eyebrows, even though we have much less body hair than chimps. D) Kiwis are flightless birds with reduced, nonfunctional wings. E) Snakes have hinged jaws to help them swallow large meals.
After the drought of 1977, researchers hypothesized that on Daphne Major, medium ground finches with large, deep beaks survived better than those with smaller beaks because they could more easily crack and eat the tough Tribulus cistoides fruits. If this hypothesis is true, what would you expect to observe if a population of these medium ground finches colonizes a nearby island where T. cistoides is the primary available food in all yea Assume that 1) even the survivors of the 1977 drought sometimes had difficulty cracking the tough T. cistoides fr and would eat other seeds when offered a choice, and 2) food availability is the primary limit on finch fitness on this new island.
A) evolution of smaller, pointier beaks over time B) random fluctuations in beak size and shape C) evolution of yet larger, deeper beaks over time D) no change in beak size and shape