Biology & Life Sciences Chapter 31 the bat fidgets and wastes calories, using up

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Campbell Biology, 10e (Reece)

Chapter 31 Fungi

Use the following information to answer the question(s) below.

In the United States and Canada, bats use one of two strategies to survive winter: They either

migrate south, or they hibernate. Recently, those that hibernate seem to have come under attack

by a fungus, Geomyces destructans (Gd), an attack that is occurring from Missouri to southern

Canada. Many infected bats have a delicate, white filamentous mat on their muzzles, which is

referred to as white-nose syndrome (WNS). The fungus invades the bat tissues, causes

discomfort, and awakens the bat from its hibernation. The bat fidgets and wastes calories, using

up its stored fat. The bat then behaves abnormally, leaving its cave during daytime in winter to

search for food. Their food, primarily insects, is scarce during the winter, and the bats ultimately

starve to death. Since 2007, it is estimated that up to one million bats have perished from WNS.

1) The Gd mat on the fur of the bats should be expected to consist of _____.

A) hyphae

B) haustoria

C) yeasts

D) basidia

2) What do fungi and arthropods have in common?

A) The haploid state is dominant in both groups.

B) Both groups are predominantly autotrophs that produce their own food.

C) Both groups use chitin for support.

D) Both groups have cell walls.

3) Fungi have an extremely high surface-area-to-volume ratio. What is the advantage of this to

an organism that gets most of its nutrition through absorption?

A) The larger surface area allows for more material to be transported through the cell membrane.

B) The lower volume prevents the cells from drying out too quickly, which can interfere with

absorption.

C) This high ratio creates more room inside the cells for additional organelles involved in

absorption.

D) This high ratio means that fungi have a thick, fleshy structure that allows the fungi to store

more of the food it absorbs.

Use the following information to answer the question(s) below.

Suzanne Simard and colleagues knew that the same mycorrhizal fungal species could colonize

multiple types of trees. They wondered if the same fungal individual would colonize different

trees, forming an underground network that potentially could transport carbon and nutrients from

one tree to another (S. Simard et al. 1997. Net transfer of carbon between mycorrhizal tree

species in the field. Nature 388:579-82).

Figure A illustrates the team’s experimental setup. Pots containing seedlings of three different

tree species were set up and grown under natural conditions for three years; two of the three

species (Douglas fir, birch) formed ectomycorrhizae and the other (cedar) formed arbuscular

mycorrhizae. For the experiment, the researchers placed airtight bags over the Douglas fir and

birch seedlings; into each bag, they injected either carbon dioxide made from carbon-13 or

carbon-14 (13CO2 and 14CO2, isotopes of carbon). As the seedlings photosynthesized, the

radioactive carbon dioxide was converted into radioactively labeled sugars that could be tracked

and measured by the researchers.

Figure A Figure B

4) Refer to Figure A. Which of the following results would support Simard et al.’s (1997)

hypothesis that fungi can move carbon from one plant to another? [Hypothesis: Sugars made by

one plant during photosynthesis can travel through a mycorrhizal fungus and be incorporated

into the tissues of another plant.]

A) Carbon-14 is found in the birch seedling’s tissues and carbon-13 in the Douglas fir.

B) Carbon-14 is found in the Douglas fir seedling’s tissues and carbon-13 in the birch.

C) Either carbon-13 or carbon-14 is found in the fungal tissues.

D) Either carbon-13 or carbon-14 is found in the cedar seedling’s tissues.

5) Based on the idea that fungi have pores between their cell walls, which allow cytoplasm to

move from one end of the mycelium to the other, which of the following hypotheses is the most

plausible?

A) If a single mycorrhizal fungus formed symbiotic associations with more than one tree, carbon

could travel from one plant to another.

B) Parasitic fungi steal nutrients from their hosts.

C) Predatory fungi capture their prey by encircling them with hyphae, and the flowing of the

cytoplasm through the pores helps the hyphae to move around the prey.

D) Fungi function as part of the global carbon cycle not only by converting carbon from one

form to another, but by physically moving it from one location to another.

Use the following information to answer the question(s) below.

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 below, 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.

6) Based on the graphs in the figure above, which of the following plant species is most likely

NOT to form mycorrhizal associations?

A) Carex flacca (graph a)

B) Lotus corniculatus (graph b)

C) Sanguisorba officinalis (graph c)

D) Centaurium erythrea (graph d)

7) If all fungi in an environment that perform decomposition were to suddenly die, then which

group of organisms should benefit most, due to the fact that their fungal competitors have been

removed?

A) flowering plants

B) protists

C) prokaryotes

D) grasses

8) When a mycelium infiltrates an unexploited source of dead organic matter, what are most

likely to appear within the food source soon thereafter?

A) fungal haustoria

B) fungal enzymes

C) increased oxygen levels

D) larger bacterial populations

9) The functional significance of porous septa in certain fungal hyphae is most similar to that

represented by which pair of structures in animal cells and plant cells, respectively?

A) desmosomes — tonoplasts

B) gap junctions — plasmodesmata

C) tight junctions — plastids

D) centrioles — plastids

10) A fungal spore germinates, giving rise to a mycelium that grows outward into the soil

surrounding the site where the spore originally landed. Which of the following accounts for the

fungal movement, as described here?

A) karyogamy

B) mycelial flagella

C) breezes distributing spores

D) cytoplasmic streaming in hyphae

11) When pathogenic fungi are found growing on the roots of grape vines, grape farmers

sometimes respond by covering the ground around their vines with plastic sheeting and pumping

a gaseous fungicide into the soil. The most important concern of grape farmers who engage in

this practice should be that the _____.

A) fungicide might also kill the native yeasts residing on the surfaces of the grapes

B) lichens growing on the vines’ branches are not harmed

C) fungicide might also kill mycorrhizae

D) sheeting is transparent so that photosynthesis can continue

12) The adaptive advantage associated with the filamentous nature of fungal mycelia is primarily

related to _____.

A) the ability to form haustoria and parasitize other organisms

B) the potential to inhabit almost all terrestrial habitats

C) the increased probability of contact between different mating types

D) an extensive surface area well suited for invasive growth and absorptive nutrition

13) Some fungal species can kill herbivores while feeding off of sugars from its plant host. What

type of relationship does this fungus have with its host?

A) parasitic

B) mutualistic

C) commensal

D) predatory

Use the following information to answer the question(s) below.

Suzanne Simard and colleagues knew that the same mycorrhizal fungal species could colonize

multiple types of trees. They wondered if the same fungal individual would colonize different

trees, forming an underground network that potentially could transport carbon and nutrients from

one tree to another (S. Simard et al. 1997. Net transfer of carbon between mycorrhizal tree

species in the field. Nature 388:579-82).

Figure A illustrates the team’s experimental setup. Pots containing seedlings of three different

tree species were set up and grown under natural conditions for three years; two of the three

species (Douglas fir, birch) formed ectomycorrhizae and the other (cedar) formed arbuscular

mycorrhizae. For the experiment, the researchers placed airtight bags over the Douglas fir and

birch seedlings; into each bag, they injected either carbon dioxide made from carbon-13 or

carbon-14 (13CO2 and 14CO2, isotopes of carbon). As the seedlings photosynthesized, the

radioactive carbon dioxide was converted into radioactively labeled sugars that could be tracked

and measured by the researchers.

Figure A Figure B

14) Referring to Simard et al. (1997), what is the result that would most strongly refute their

hypothesis? [Hypothesis: Sugars made by one plant during photosynthesis can travel through a

mycorrhizal fungus and be incorporated into the tissues of another plant.]

A) No movement: Carbon-14 is found in the birch seedling’s tissues and carbon-13 in the

Douglas fir.

B) Reciprocal exchange: Carbon-14 is found in the Douglas fir seedling’s tissues and carbon-13

in the birch.

C) Either carbon-13 or carbon-14 is found in the fungal tissues.

D) Either carbon-13 or carbon-14 is found in the cedar seedling’s tissues.

15) Referring to Simard et al. (1997), which design element is the control in this experiment and

why?

A) the bags over the seedlings to contain the different types of carbon dioxide

B) the fact that all the seedlings are different species

C) the cedar seedling, because it is not bagged

D) the cedar seedling, because it forms arbuscular mycorrhizae

16) Simard et al. (1997) further hypothesized that if reciprocal transfer did occur, it would be a

source-sink relationship driven by photosynthetic rates. That is, if one seedling is in full sun and

the other in deep shade, there will be a net movement of carbon from the seedling in full sun to

the one in deep shade. If a shade was placed over the birch seedlings and the cedar, and the

Douglas fir was left in full sun, what result could Simard and colleagues expect?

A) More 13C would be found in the birch than in the Douglas fir.

B) More 13C would be found in the Douglas fir than in the birch.

C) The most 13C would be found in the cedar.

D) The most 14C would be found in the cedar.