Fungi

(a) In Table 1, which fungal species has the most genes encoding membrane transporters (membrane transport proteins; see Concept 7.2)? (b) Why might these genes be of particular importance to L. bicolor?

The phrase “small secreted proteins” (SSPs) refers to proteins less than 100 amino acids in length that the fungi secrete; their function is not yet known. (a) Describe the Table 1 data on SSPs. (b) The researchers found that the SSP genes shared a common feature that indicated the encoded proteins were destined for secretion. Based on Figure 17.22 and the text discussion of that figure, predict what this common feature of the SSP genes was. (c)Suggest a hypothesis for the roles of SSPs in mycorrhizae.

Table 2 shows data from gene expression studies for the four L.bicolor genes whose transcription was most increased (“upregulated”) in mycorrhizae. (a) For the gene encoding the first protein listed, what does the number 22,877 indicate? (b)Do the data in Table 2 support your hypothesis in 2(c)? Explain. (c) Compare the data for poplar mycorrhizae with those for Douglas fir and hypothesize what might account for any differences.

Suppose a certain fungus is a mutualist that lives within an insect host, yet its ancestors were parasites that grew in and on the insect’s body. What derived traits might you find in this mutualistic fungus?

Compare and contrast the nutritional mode of a fungus with your own nutritional mode.

Review Figure 10.4 and Figure 10.6. If a plant has mycorrhizae, where might carbon that enters the plant’s stomata as CO₂ eventually be deposited: in the plant, in the fungus, or both? Explain.

Compare Figure 31.5 with Figure 13.6. In terms of haploidy versus diploidy, how do the life cycles of fungi and humans differ?

Suppose that you sample the DNA of two mushrooms on opposite sides of your yard and find that they are identical. Propose two hypotheses that could reasonably account for this result.

Why are fungi classified as opisthokonts despite the fact that most fungi lack flagella?

Describe the importance of mycorrhizae, both today and in the colonization of land. What evidence supports the antiquity of mycorrhizal associations?

If fungi colonized land before plants, where might the fungi have lived? How would their food sources have differed from what they feed on today?

What feature of chytrids supports the hypothesis that they include members of basal fungal lineages?

Give examples of how form fits function in zygomycetes, glomeromycetes, ascomycetes, and basidiomycetes.

WHAT IF? Suppose that the mutation of an ascomycete changed its life cycle so that plasmogamy, karyogamy, and meiosis occurred in quick succession. How might this affect the ascospores and ascocarps?

What are some of the benefits that lichen algae can derive from their relationship with fungi?

What characteristics of pathogenic fungi result in their being efficiently transmitted?

WHAT IF? How might life on Earth differ from what we know today if no mutualistic relationships between fungi and other organisms had ever evolved?

All fungi are 

(A) symbiotic. 

(B) heterotrophic. 

(C) flagellated. 

(D) decomposers.

Which of the following cells or structures are associated with asexual reproduction in fungi? 

(A) ascospores 

(B) basidiospores 

(C) zygosporangia 

(D) conidiophores

The most important adaptive advantage associated with the filamentous nature of fungal mycelia is 

(A) the ability to form haustoria and parasitize other organisms. 

(B) the potential to inhabit almost all terrestrial habitats. 

(C) the increased chance of contact between mating types. 

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

The closest relatives of fungi are thought to be the 

(A) animals. 

(B) vascular plants. 

(C) mosses. 

(D) slime molds.

The grass Dichantheliumlanuginosum lives in hot soils and houses fungi of the genus Curvularia as endophytes. Researchers tested the impact of Curvularia on the heat tolerance of this grass. They grew plants without (E-) and with (E+) Curvularia endophytes at different temperatures and measured plant mass and the number of new shoots the plants produced. Draw a bar graph for plant mass versus temperature and interpret it.

The fungus-alga symbiosis that makes up a lichen is thought to have evolved multiple times independently in different fungal groups. However, lichens fall into three well-defined growth forms (see Figure 31.22). How could you test the following hypotheses? Hypothesis1: Crustose, foliose, and fruticose lichens each represent a monophyletic group. Hypothesis 2: Each lichen growth form represents convergent evolution by taxonomically diverse fungi.

As you read in this chapter, fungi have long formed symbiotic associations with plants and with algae. In a short essay (100–150 words), describe how these two types of associations may lead to emergent properties in biological communities.

This wasp is the unfortunate victim of an entomopathogenic fungus (a parasitic fungus of insects). Write a paragraph describing what this image illustrates about the nutritional mode, body structure, and ecological role of the fungus.