WEEK 6: Chapter 28 & 31 Homework Assignment

If Bd cannot grow properly at temperatures above 28°C (82°F), then, assuming the amphibians can survive, in which time or place should the chytrid infection proceed most rapidly?1. cooler months2. warmer months3. lower altitudes4. higher altitudes

1,4

If a single, diploid G2 nucleus in an ascus contains 400 nanograms (ng) of DNA, then a single ascospore nucleus of this species should contain how much DNA (ng), carried on how many chromosomes?

100, carried on 7 chromosomes

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.]

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

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.Based on the graphs in the figure above, which of the following plant species is most likely NOT to form mycorrhizal associations?

Carex flacca (graph a)

You observe the gametes of a fungal species under the microscope and realize that they resemble animal sperm. To which of the following group does the fungus belong?

Chytrids

Assume that all four locations are 0.5 meters above the surface. On a breezy day with prevailing winds blowing from left to right, where should one expect to find the highest concentration of free basidiospores in an air sample?

D

At which location should one find the lowest concentration of fungal enzymes, assuming that the enzymes do not diffuse far from their source, and that no other fungi are present in this habitat?

D

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.]

Either carbon-13 or carbon-14 is found in the cedar seedling's tissues.

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?

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

When adult amphibian skin harbors populations of the bacterium, Janthinobacterium lividum (Jl), chytrid infection seems to be inhibited. Which of the following represents the best experimental design to test whether this inhibition is real?

Take infected amphibians and assign them to two populations. Leave one population alone; inoculate the other with Jl. Measure the rate at which infection proceeds in both populations.

Living diatoms contain brownish plastids. If global warming causes blooms of diatoms in the surface waters of Earth's oceans, how might this be harmful to the animals that build coral reefs?

The coral animals' endosymbiotic dinoflagellates may get "shaded out" by the diatoms.

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?

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

Basidiomycetes are the only fungal group capable of synthesizing lignin peroxidase. What advantage does this group of fungi have over other fungi because of this capability?

This fungal group can break down the tough lignin, which cannot be harnessed for energy, to get to the more useful cellulose.

Theoretically, P. bursaria can obtain zoochlorella either vertically (via the asexual reproduction of its mother cell) or horizontally (by ingesting free-living Chlorella from its habitat). Consider a P. bursaria cell containing zoochlorellae but whose habitat lacks free-living Chlorella. If this cell subsequently undergoes many generations of asexual reproduction, if all of its daughter cells contain roughly the same number of zoochlorellae as it had originally contained, and if the zoochlorellae are all haploid and identical in appearance, then what is true? The zoochlorellae _____.

also reproduced asexually, at a fairly constant rate over time

Similar to most amoebozoans, the forams and the radiolarians also have pseudopods, as do some of the white blood cells of animals (monocytes). If one were to erect a taxon that included all organisms that have cells with pseudopods, the taxon would _____.

be polyphyletic

Orchid seeds are tiny, with virtually no endosperm and with miniscule cotyledons. If such seeds are deposited in a dark, moist environment, then which of the following represents the most likely means by which fungi might assist in seed germination, given what the seeds lack?

by providing the embryos with some of the organic nutrients they have absorbed

Which of the following have chloroplasts (or structures since evolved from chloroplasts) thought to be derived from ancestral green algae?

chlorarachniophytes

You are given an unknown organism to identify. It is unicellular and heterotrophic. It is motile, using many short extensions of the cytoplasm, each featuring the 9 + 2 filament pattern. It has well-developed organelles and two nuclei, one large and one small. This organism is most likely to be a _____.

ciliate

Which of the following pairs of protists and their characteristics is mismatched?

ciliates — red tide organisms

Fossil fungi date back to the origin and early evolution of plants. What combination of environmental and morphological change is similar in the evolution of both fungi and plants?

colonization of land and loss of flagellated cells

Which process in Paramecium results in genetic recombination but no increase in population size?

conjugation

The chloroplasts of land plants are thought to have been derived according to which evolutionary sequence?

cyanobacteria → green algae → land plants

Super cells characteristic of plasmodial slime molds result when which one of the following common cellular processes does not occur?

cytokinesis

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?

cytoplasmic streaming in hyphae

The cysts of Giardia function most like the _____.

endospores of bacteria

All protists are _____.

eukaryotic

A snail-like, coiled, porous test (shell) of calcium carbonate is characteristic of _____.

foraminiferans

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 _____.

fungicide might also kill mycorrhizae

A large seaweed that floats freely on the surface of deep bodies of water would be expected to lack which of the following?

holdfasts

Which process could have allowed the nucleomorphs of chlorarachniophytes to be reduced, without the net loss of any genetic information?

horizontal gene transfer

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

hyphae

Mycorrhizae are to the roots of vascular plants as endophytes are to vascular plants' _____.

leaf mesophyll

Which of the following has the LEAST affiliation with all of the others?

lichens

Assume that some members of an aquatic species of motile, photosynthetic protists evolve to become parasitic to fish. They gain the ability to live in the fish gut, absorbing nutrients as the fish digests food. Over time, which of the following phenotypic changes would you expect to observe in this population of protists?

loss of chloroplasts

Giardia's mitosome can be said to be "doubly degenerate," because it is a degenerate type of ________, an organelle that is itself a degenerate form of ________.

mitochondria; proteobacterium

Healthy individuals of Paramecium bursaria contain photosynthetic algal endosymbionts of the genus Chlorella. When within their hosts, the algae are referred to as zoochlorellae. In aquaria with light coming from only one side, P. bursaria gather at the well-lit side, whereas other species of Paramecium gather at the opposite side. The zoochlorellae provide their hosts with glucose and oxygen, and P. bursaria provides its zoochlorellae with protection and motility. P. bursaria can lose its zoochlorellae in two ways: (1) if kept in darkness, the algae will die; and (2) if prey items (mostly bacteria) are absent from its habitat, P. bursaria will digest its zoochlorellae.Which term most accurately describes the nutritional mode of healthy P. bursaria?

mixotroph

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?

mutualistic

If the mitosomes of Giardia contain no DNA, yet are descendants of what were once free-living organisms, then where are we likely to find the genes that encode their structures, and what accounts for their current location there?

nucleus; horizontal gene transfer

Which of the following groups is matched with a correct anatomical feature?

phaeophyta (brown algae) → blade

When light, especially red and blue light, is shone on the tubes, oxygen bubbles accumulate on the inside of test tubes 1 and 2. Chemical analysis of test tube 1 indicates the presence of a chemical that is toxic to fish and humans. Chemical analysis of test tube 2 indicates the presence of substantial amounts of silica. Microscopic analysis of organisms in test tubes 1, 3, and 4 reveals the presence of permanent, membrane-bounded sacs just under the plasma membrane. Microscopic analysis of organisms in test tube 3 reveals the presence of an apicoplast in each. Microscopic analysis of the contents in test tube 4 reveals the presence of one large nucleus and one small nucleus in each organism.Test tube 3 contains _____.

plasmodium

At which stage of a basidiomycete's life cycle would reproduction be halted if an enzyme that prevented the fusion of hyphae was introduced?

plasmogamy

In most fungi, karyogamy does not immediately follow plasmogamy, which consequently _____.

results in heterokaryotic or dikaryotic cells

Given the eukaryotic structures they lack, it should be expected that microsporidians also lack _____.

the "9 + 2 pattern" of microtubules

Green algae differ from land plants in that many green algae _____.

unicellular