Use the Following Information to Answer the Question

question 30

Multiple Choice

Use the following information to answer the question.
There is much discussion in the media about protecting biodiversity. But does biodiversity really matter? Canadian and Swiss researchers wanted to know if the diversity of arbuscular mycorrhizal fungi (AMF) was important to the productivity of grasslands (M.G.A. van der Heijden, J. N. Klironomos, M. Ursic, P. Moutoglis, R. Streitwolf-Engel, T. Boler, A. Wiemken, and I. R. Sanders. 1998. Mycorrhizal fungal diversity determines plant biodiversity, ecosystem variability, and productivity. Nature 396:69-72) . Specifically, they wanted to know if it mattered which specific AMF species were present, or just that some type of AMF was present. They grew various plants in combination with one of four AMF species (A, B, C, and D) , no AMF species (O) , or all four AMF species together (A + B + C + D) ; and they measured plant growth under each set of conditions. All plant species were grown in each plot, so they always competed with each other, with the only difference being which AMF species were present.
On the graphs, the x-axis labels indicate the number and identity of AMF species (bar 0 = no fungi; bars A - D = individual AMF species; bar A + B + C + D = all AMF species together) . The y-axis indicates the amount (grams) of plant biomass for the species shown in italics above each graph.

In graph b in the figure, which of the following best explains the data given about Lotus corniculatus?

• A) This plant grows best when AMF taxa A or C is present.
• B) Lotus corniculatus does not form mycorrhizal associations.
• C) Mycorrhizal fungi parasitize the plant's roots when they are present, reducing its growth.
• D) This plant forms multiple AMF associations, growing best with increased fungal diversity.

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Definitions:

Carboniferous

The Carboniferous is a geologic period and system that extends from about 359 to 299 million years ago, known for its vast coal deposits.

Ordovician

A geologic period and system of the Paleozoic Era, following the Cambrian and preceding the Silurian, marked by significant diversification of life.

Natural Selection

The process by which organisms better adapted to their environment tend to survive and produce more offspring.

Triassic

A geological period that occurred approximately 252 to 201 million years ago, marking the beginning of the Mesozoic Era.