RQ30: Mutualism and Coevolution

Some beetles that visit flowers to harvest nectar get into the flower by chewing through the sides of the petals. As a result, they do not become dusted with pollen. Is this a mutualistic interaction? a) No-these beetles are acting as consumers, not mutualists b) Yes-because the beetles are entering the flower, the plant is receiving a fitness benefit c) Yes-pollination is a classic example of a mutualism d) No-this is an example of "deceit pollination"

a) No-these beetles are acting as consumers, not mutualists

The birds the alligator is describing in this Far Side cartoon behave similarly to the cleaner shrimp discussed in the text. Explain the joke. Alligator says: "You know those teeny tiny little birds that walk around so trustingly inside a crocodile's mouth? Well, I just been eatin' those little guys like popcorn." a) The alligator has guilt because it hasn't been acting as a mutualist b) To an alligator, little birds ARE like popcorn-a tasty snack c) There is no joke-mutualisms are dynamic, and are "a kind of reciprocal parasitism" d) It's ridiculous to think of an alligator in a psychiatrist's office

a) The alligator has guilt because it hasn't been acting as a mutualist

What does it mean to say that mutualism is a +/+ interaction? a) Both species in the interaction experience lower fitness b) Both species in the interaction receive a fitness benefit c) Both species experience natural selection during get during the interaction (coevolution occurs) d) Both species are present during the interaction

b) Both species in the interaction receive a fitness benefit

What is the nature of the fungal-plant mutualism mentioned in the text? a) Fungi infect an array of plant tissues; lints have an array of defenses b) Fungi provide key nutrients to the plant; the plant provides photosynthetic products c) Fungi produce antibiotics that protect the plant; the plant provides photosynthetic products d) The fungi provide compounds that deter herbivores; the plant provides protection

b) Fungi provide key nutrients to the plant; the plant provides photosynthetic products

What is the nature of the bacteria-plant mutualism mentioned in the text? a) The bacteria live in specialized root nodules b) The bacteria "fix" atmospheric nitrogen; the plant provides protection and nutrients c) The bacteria synthesize defense compounds; the plant provides photosynthetic products d) The association is found only in a few plant species

b) The bacteria "fix" atmospheric nitrogen; the plant provides protection and nutrients

Why is it accurate to claim that the ant-treehopper mutualism described in the text is "contingent?" a) Mutualists are best thought of as "reciprocal parasitism," with each species under selection to maximize its fitness benefits b) The fitness benefit to treehoppers depends on the presence of spiders (a predator) c) The fitness benefit to the ants depends on the presence of spiders (a predator)

b) The fitness benefit to treehoppers depends on the presence of spiders (a predator)

Why did it turn out to be important that the researchers ran the ant-treehopper study for two years? a) Because it takes ants and treehoppers at least a year to learn to work together b) Because one year's worth of data was not enough to produce statistically significant results c) Because the fitness consequences of having ants present varied dramatically across years d) Because treehoppers don't reproduce until they are two years old

c) Because the fitness consequences of having ants present varied dramatically across years

In the ant-treehopper study illustrated in the text, why did the scientists assign plants in the study plot to the ants-present versus ants-removed groups at random-instead of, for example, assigning all the plants on the west side of the plot to the ant-present group and all the plants on the east side to the ants-removed group? a) To prevent the plants from learning which treatment group they were in b) Because the west side of the plot was larger than the east side c) To make sure they had roughly equal numbers of plants in each group d) To control for differences among regions of the study plot that might influence the fitness of the treehoppers

d) To control for differences among regions of the study plot that might influence the fitness of the treehoppers