Use the Following Information to Answer the Question

question 39

Multiple Choice

Use the following information to answer the question.
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. Graph e is the total biomass (grams) of all 11 plant species combined; graph f is the biomass of Bromus erectus plants only, separated from the total.

Based on graphs e and f, which is the most well-supported prediction for the effect on total plant biomass if AMF diversity were increased to eight species?

• A) No effect is predicted, because the dominant species is unaffected by AMF diversity
• B) Total biomass for eight species would double in comparison to that for four species.
• C) Rare species would produce more biomass compared to the case when fewer AMF are present.
• D) No effect is predicted, because the dominant species is non-mycorrhizal.

---

Definitions:

New Regulations

Recently implemented rules or laws designed to control or govern conduct, usually within a specific activity or industry.

Appliance Producers

companies engaged in the manufacture of electrical or mechanical devices designed for household use.

Crony Capitalism

A type of economic system where business success is heavily influenced by close relationships between business owners and government officials.

Government Regulation

Government regulation encompasses the laws and rules set forth by the government intended to control or manage certain practices, activities, or behaviors within an economy or society.