Taxonomy, Microorganism, Protists & Fungi Questions

Modified True/False

Indicate whether the statement is true or false. If false, change the identified word or phrase to make the statement true.

____1.Linnaeus used similarities in structure to determine relationships among organisms. _________________________

____2.Streptococcus, a type of bacteria that causes strep throat, is classified in the Kingdom Protista. _________________________

____3.When organisms are classified within the same group, it can be assumed that they have a common phylogeny. _________________________

____4.In a fan diagram, the closer a species is to the outer band, the earlier it appeared in geologic time. _________________________

____5.A dichotomous key is a step-by-step way to identify an organism using a series of paired descriptions. _________________________

____6.In the name of the white oak, Quercus alba, Quercus is the species name. _________________________

____7.A phylum is related to a class as a family is related to an order. _________________________

____8.Organisms that are similar in structure and form and successfully reproduce among themselves belong to the same family. _________________________

____9.The greater the number of taxa two organisms have in common, the more closely related they are. _________________________

____10.In Aristotle's system of classification, animals were classified on the basis of their size and structure. _________________________

____11.A lichen is the result of a mutual relationship between a fungus and an algae or cyanobacteria. _________________________

____12.Mycorrhizae is a mutualistic relationship between fungi and algae. _________________________

____13.Basidiospores are produced by mushrooms. _________________________

____14.Zygospores are found in saclike structures produced by specialized hyphae. _________________________

____15.Specialized hyphae called haustoria penetrate the cells of a host tree and provide additional surface for absorption of water and minerals. _________________________

____16.A unique feature of fungal decomposition is that organic material is digested inside the fungal cells. _________________________

____17.No fungus contains chlorophyll in its hyphal cells. _________________________

____18.All fungi have cell walls made of cellulose. _________________________

____19.Bread mold is able to penetrate the bread by means of zygospores. _________________________

____20.The fungus that produces penicillin is an example of a basidiomycote. _________________________

____21.Mushrooms are examples of club fungi. _________________________

____22.The short-lived reproductive structure in mushrooms is the mycelium. _________________________

____23.Mycorrhizae increase the reproductive surface of plant roots. _________________________

____24.During asexual reproduction, ascomycotes produce ascospores. _________________________

Multiple Choice

Identify the choice that best completes the statement or answers the question.

____25.The evolutionary history of a species is its _____.

a.

biodiversity

c.

extinction

b.

phylogeny

d.

taxonomy

____26.A system for naming species in which two words are used to name an organism is _____.

a.

binomial nomenclature

c.

cladistics

b.

dichotomous keying

d.

fan diagramming

____27.The placing of information or objects into groups based on certain similarities is _____.

a.

biochemical analysis

c.

phylogeny

b.

classification

d.

speciation

____28.A heterotrophic eukaryote associated with the decomposition of dead organisms is a(n) _____.

a.

bacterium

c.

fungus

b.

herbivore

d.

protist

____29.A group of related classes of plants is a _____.

a.

database

c.

division

b.

kingdom

d.

taxon

____30.The science of grouping and naming organisms is _____.

a.

classification

c.

nomenclature

b.

phylogeny

d.

taxonomy

____31.The method used to construct a hypothetical evolutionary tree is ____.

a.

biochemistry

c.

DNA sequencing

b.

cladistics

d.

statistical analysis

____32.Biologists use ______________ to create a cladogram.

a.

derived traits

c.

discretionary

b.

behavioral

d.

pedigrees

____33.Which of the bacteria is the cause of pneumonia?

a.

staphylococci

c.

Treponema pallidum

b.

rickettsia

d.

streptococcus pneumoniae

____34.Bacteria are used in _____.

a.

farming

c.

the food industry

b.

the medical industry

d.

all of these

____35.A structure in some bacteria that is resistant to adverse environmental factors is a(n) _____.

a.

prophage

c.

autotroph

b.

endospore

d.

coccus

____36.Which of the following is NOT an evolutionary adaptation in bacteria?

a.

They reproduce rapidly.

b.

They have a high rate of mutation.

c.

They cannot exist under adverse conditions.

d.

They can utilize substances harmful to other organisms.

____37.Which of the following processes brings about an exchange of genetic information between bacterial cells?

a.

binary fission

c.

conjugation

b.

mutualism

d.

replication

____38.A(n) _____ is a virus that infects a bacterial cell.

a.

endospore

c.

plasmid

b.

decomposer

d.

bacteriophage

____39.Viruses are found in _____.

a.

air

c.

soil

b.

water

d.

all of these

____40.Viruses are _____.

a.

producers

c.

parasites

b.

consumers

d.

decomposers

____41.Penicillin kills bacteria by _____.

a.

consuming them

b.

causing holes to develop in their cell walls

c.

imprisoning them

d.

depriving them of nutrients

____42.The name streptococcus tells you that the bacteria are arranged as _____.

a.

pairs of round cells

c.

groups of spirals

b.

long chains of round cells

d.

chains of rods

____43.Cyanobacteria are _____.

a.

eubacterial heterotrophs

c.

salt-loving archaebacteria

b.

photosynthetic autotrophs

d.

chemosynthetic autotrophs

____44.Downy mildews and water molds are similar to fungi in that they both _____.

a.

resemble fungi

c.

absorb nutrients

b.

decompose organic materials

d.

all of these

____45.Downy mildews are important because they may cause serious _____.

a.

animal diseases

c.

protist declines

b.

plant diseases

d.

all of these

____46.Economically important members of the phylum Oomycota include _____.

a.

plasmodial slime molds

c.

water molds

b.

cellular slime molds

d.

all of these

____47.The funguslike protists that produce a multinucleate glob of cytoplasm are the _____.

a.

water molds

c.

downy mildews

b.

plasmodial slime molds

d.

cellular slime molds

____48.The plantlike protists that are the cause of red tides are _____.

a.

red algae

c.

brown algae

b.

dinoflagellates

d.

blue-green algae

____49.The plantlike protists with delicate shells that make up a large proportion of the phytoplankton in freshwater ecosystems are _____.

a.

diatoms

c.

sporozoans

b.

dinoflagellates

d.

green algae

____50.Members of the Kingdom Protista have _____.

a.

membrane-bound organelles

c.

one or many cells

b.

a wide variety of sizes and shapes

d.

all of these

____51.A protozoan that moves by lashing one or more of its whiplike parts is a(n) _____.

a.

thallus

c.

water mold

b.

sporozoan

d.

flagellate

____52.Which protist group produces much of the oxygen on Earth?

a.

diatoms

c.

water molds

b.

algae

d.

slime molds

____53.Slime molds are said to be like animals during much of their life cycle because they _____.

a.

look like animals

b.

reproduce by making spores

c.

move about and engulf food

d.

grow on rotting leaves or tree stumps

____54.Dinoflagellates are able to spin by means of _____.

a.

the cilia that emerge through their pellicle

b.

two flagella at right angles to each other

c.

a pillbox shell that opens and closes

d.

a holdfast that attaches them to a rock

____55.During the gametophyte generation, a green alga _____.

a.

has the haploid number of chromosomes

b.

has the diploid number of chromosomes

c.

reproduces asexually

d.

develops from a zygote

____56.Most sporozoans reproduce by _____.

a.

conjugation

c.

fragmentation

b.

sexual reproduction only

d.

both sexual and asexual reproduction

____57.An amoeba engulfs food by _____.

a.

using its oral groove and the action of cilia

b.

osmosis

c.

surrounding the food with pseudopodia

d.

forming cysts

____58.Many protozoans are classified according to _____.

a.

their method of waste removal

c.

their method of reproduction

b.

the way that they move

d.

their habitats

Figure 19-2

____59.Which structure shown in Figure 19-2 is used for locomotion?

a.

A

c.

C

b.

B

d.

D

____60.Which structure shown in Figure 19-2 is used to eat?

a.

A

c.

C

b.

B

d.

D

____61.Which structure shown in Figure 19-2 is used to extract waste?

a.

A

c.

C

b.

B

d.

D

Figure 19-3

____62.Which of the protists shown in Figure 19-3 would use a pseudopod?

a.

A

c.

C

b.

B

d.

D

____63.Which of the protists shown in Figure 19-3 has the hardest exterior?

a.

A

c.

C

b.

B

d.

D

Figure 19-4

____64.Which phase shown in Figure 19-4 is diploid?

a.

gametophyte

c.

from the zygote to the sporophyte

b.

from the spore to the gametophyte

d.

male and female gametophytes

____65.When does meiosis occur in Figure 19-4?

a.

when the gametes form

b.

when the spores form

c.

when the zygotes form

d.

when the male and female gametophytes form

____66.When does mitosis occur in Figure 19-4?

a.

only as the zygote forms

b.

only when the male and female gametophytes make the gametes

c.

only as spores grow into gametophytes

d.

any time there is cellular growth

____67.Fossils of fungi are rare due to _____.

a.

their late appearance on the Geologic Time Scale

b.

their lack of species diversity

c.

their composition of soft materials

d.

their ability to form protective zygospores

____68.The bread mold, Rhizopus, produces sexual zygospores when _____.

a.

environmental conditions are unfavorable

b.

environmental conditions are favorable

c.

there is moist food

d.

rhizoids are present

____69.In hyphae divided by septa, cytoplasm flows from one cell to the next through _____.

a.

haustoria

c.

spores

b.

chitin

d.

pores

____70.Fungi that transform complex organic substances into raw materials that other organisms can use are _____.

a.

parasites

c.

decomposers

b.

mutualists

d.

autotrophs

____71.One criterion for classifying fungi is by how they _____.

a.

form symbiotic relationships

c.

obtain their food

b.

reproduce

d.

recycle nutrients

Figure 20-2

____72.In Figure 20-2, where are spores formed?

a.

A

c.

C

b.

B

d.

D

____73.In Figure 20-2, which structures gather nutrients?

a.

A

c.

C

b.

B

d.

D

____74.In Figure 20-2, where will sexual reproduction happen?

a.

A

c.

C

b.

B

d.

D

____75.In Figure 20-2, which structure acts as an anchor?

a.

A

c.

C

b.

B

d.

D

____76.In Figure 20-2, what would cause a zygospore to form at B?

a.

moisture

c.

an overabundance of food

b.

unfavorable environmental conditions

d.

heat

Figure 20-3

____77.Where are spores released in the organism shown in Figure 20-3?

a.

A

c.

C

b.

B

d.

D

____78.Where does meiosis in the organism shown in Figure 20-3?

a.

A

c.

C

b.

B

d.

D

Figure 20-4

____79.According to Figure 20-4, which type of fungi has the most species?

a.

deuteromycotes

c.

lichens

b.

basidiomycotes

d.

ascomycotes

____80.Mushrooms, which are basidiomycostes, make up what percentage of the fungi species, according to Figure 20-4?

a.

4%

c.

25%

b.

20%

d.

50%

Completion

Complete each statement.

81.The language used for scientific names is ____________________ because it does not change.

82.Aristotle classified animals according to their ____________________ and ____________________.

83.Aristotle classified plants into three groups based on ____________________ and ____________________.

84.Scientists used a system of ____________________ to help understand the relationships between organisms.

Figure 18-1

85.The virus attaching to a host cell is shown in stage ____________________ of Figure 18-1.

86.New virus particles are assembled in stage ____________________ of Figure 18-1.

87.Virus injecting its nucleic acid into the host cell is shown in stage ____________________ of Figure 18-1.

88.The host cell breaks open, and the new virus particles are released, as shown in stage ____________________ of Figure 18-1.

89.The host DNA is destroyed, and the viral genes are copied as shown in stage ____________________ of Figure 18-1.

Matching

Match each item with the correct statement below.

a.

phylum

e.

family

b.

order

f.

bacteria

c.

protist

g.

class

d.

kingdom

h.

genus

____90.group of related families

____91.group of related classes

____92.group of related species

____93.group of related genera

____94.eukaryote lacking complex organ systems

____95.group of related orders

____96.microscopic, single-celled prokaryotes

____97.group of related phyla

Match each item with the correct statement below.

a.

conjugation

f.

binary fission

b.

reverse transcriptase

g.

toxin

c.

bacteriophage

h.

virus

d.

nitrogen fixation

i.

host cell

e.

endospore

____98.enzyme injected into a host cell, which copies viral RNA into DNA

____99.cell in which a virus reproduces

____100.bacterial form that is in a state of slow metabolism and that does not reproduce

____101.process by which bacteria reproduce asexually

____102.simple form of sexual reproduction

____103.virus that infects bacteria

____104.process by which some bacteria convert N2 gas into ammonia

____105.nonliving particle that can reproduce when in a living cell

____106.poison produced by some bacteria

Match each item with the correct statement below.

a.

protozoan

g.

sporophyte

b.

spore

h.

algae

c.

gametophyte

i.

fragmentation

d.

colony

j.

ciliate

e.

pseudopodia

k.

asexual reproduction

f.

alternation of generations

l.

plasmodium

____107.life cycle of organisms that have a haploid stage followed by a diploid stage

____108.kind of reproduction in which a single parent produces offspring identical to itself

____109.extensions of a protozoan's plasma membrane, which function in getting food and in locomotion

____110.the diploid form of an alga that develops from a zygote and produces spores

____111.a group of cells that live together in close association

____112.in slime molds, the mass of cytoplasm that contains many diploid nuclei but no cell walls or membranes

____113.the haploid form of an alga that produces gametes

____114.a kind of reproduction that occurs when an individual breaks up into pieces, each of which grows into a new individual

____115.multicellular and unicellular photosynthetic protists

____116.a reproductive cell that can produce a new organism without fertilization

____117.a protozoan that moves by beating hairlike parts that cover its cell

____118.an animal-like protist

Match each item with the correct statement below.

a.

lichen

f.

stolons

b.

chitin

g.

sporangium

c.

gametangium

h.

zygospore

d.

haustoria

i.

ascospore

e.

mycorrhiza

j.

ascus

____119.in zygomycotes, the haploid structure in which gametes are produced

____120.symbiotic association in which a fungus lives in close contact with the roots of a plant partner

____121.spore produced by sac fungi

____122.saclike structure in which sexual spores develop in some fungi

____123.symbiotic association between a fungus and a green alga or cyanobacterium

____124.complex carbohydrate in the cell walls of fungi

____125.hyphae that grow horizontally along the surface of a food source

____126.thick-walled spores adapted to withstand unfavorable conditions

____127.case in which asexual spores are produced

____128.in parasitic fungi, specialized hyphae that penetrate cells and absorb nutrients

Short Answer

129.Classify each of the items in Figure 17-1 as a bacterium, protist, or fungus.

Figure 17-1

130.Aristotle classified animals according to where they lived. Classify objects in your classroom in the same way.

131.If you observed green material on the surface of a pond, how could you determine whether it belonged to Kingdom Protista or Kingdom Eubacteria?

132.If you observed green, cellular, threadlike structures on a dead leaf, to what kingdom might this organism belong?

133.If you observed gray, threadlike structures on the surface of a leaf, how could you determine whether they were spiderwebs or fungi?

134.Make a list of the taxonomic categories in order from the largest category to the smallest category. Also include groups below the level of species.

135.On what basis can members of one kingdom be distinguished from those of another kingdom?

136.What are three advantages of using scientific names for organisms?

137.What was one shortcoming of Aristotle's classification system?

138.In what way are bacteria and many protists alike?

139.In what way are fungi and plants alike?

140.In what way are protists and fungi alike?

Organism

House cat

Red fox

Dog

Wolf

Gopher

Fly

Kingdom

Animalia

Animalia

Animalia

Animalia

Animalia

Animalia

Phylum

Chordata

Chordata

Chordata

Chordata

Chordata

Arthropoda

Class

Mammalia

Mammalia

Mammalia

Mammalia

Mammalia

Insecta

Order

Carnivora

Carnivora

Carnivora

Carnivora

Rodentia

Diptera

Family

Felidae

Canidae

Canidae

Canidae

Geomyidae

Muscidae

Genus

Felis

Vulpes

Canis

Canis

Thomomys

Musca

Species

F. domesticus

V. fulva

C. familiaris

C. lupus

T. bottae

M. domestica

Table 17-2

141.How does Table 17-2 indicate that a dog is more closely related to a red fox than a house cat?

142.At what level does the relationship between gophers and house cats diverge? Refer to Table17-2.

143.From Table 17-2, which two animals are most closely related? Explain.

144.What is the complete classification of Vulpes velox? Use Table 17-2.

145.What kind of animal is Vulpes velox? How do you know? Use Table 17-2.

When a sample solution of DNA is heated to about 80C, the DNA "melts," separating into single strands of nucleotide bases. If the sample is cooled slightly and incubated, matching sequences begin to reassociate. The solution can then be filtered to allow the single strands to pass through.

One technique for comparing DNA of different species involves the labeling of single strands of DNA with radioactive iodine and using the labeled DNA to form hybrid DNA. In this procedure, a small amount of labeled, single-stranded DNA from one organism is mixed with a large amount of unlabeled, single-stranded DNA from another organism, and the mixture is incubated over time. A percentage of the strands form hybrid DNA consisting of one labeled and one unlabeled strand (see Figure 17-2A).

The more closely related the organisms, the greater the number of matched sequences there will be along these strands (see Figure 17-2B). Hybrid DNA with a high proportion of matched sequences melts at higher temperatures than that with a low proportion of matched sequences.

Figure 17-2

146.Referring to Figure 17-2, what control could you devise?

147.What would be the independent and dependent variables in your experiment? See Figure 17-2.

148.How could you use the hybrid DNA technique to test your hypothesis? Refer to Figure 17-2.

149.What is one hypothesis you could form about the relationship among bird groups A, B, and C of Figure 17-2, based on the given information?

150.A solution containing Hybrid A in Figure 17-2 is heated at stages of 2.5 degrees from 55C to 95C and filtered at each stage to let single strands of DNA pass through. The radioactivity of the filtered material is measured at each stage. Would you expect to find higher radioactivity levels at 60C or 85C? Why?

151.Which hybrid DNA in Figure 17-2 would melt at a lower temperature when heated?

152.Which hybrid DNA in Figure 17-2 was formed by DNA from two closely related organisms?

153.Compare and contrast provirus and retrovirus.

154.Compare and contrast lytic cycle and lysogenic cycle.

155.Describe the adaptations bacteria might have to live in an extreme habitat.

156.Discuss how bacteria have adapted to their diverse habitats.

157.Why aren't viruses named according to the rules of binomial nomenclature?

158.How are viruses classified according to nucleic acid? Give an example of a virus from each type.

159.Why is penicillin ineffective in destroying viruses or animal cells?

160.How does a virus recognize its host?

161.Why are viruses not considered to be living things?

162.Explain in your own words what happens in parts 1, 2, and 3 of the lysogenic cycle shown in the diagram in Figure 18-2.

Figure 18-2

163.For a period of time, bacteria were classified as plants. Why do you think bacteria were classified this way? Give at least two reasons why bacteria should not be classified as plants.

164.Why do physicians sometimes advise patients who are taking antibiotics to eat yogurt?

165.What conditions in developed countries may check the spread of bacteria that cause disease?

166.According to Table 18-1, what is the chief cause of death in developing countries? In developed countries? How does Table 18-1 reflect the fact that the availability of antibiotics affects the number of deaths due to infectious diseases?

Percentage of Deaths

Developed countries

Developing countries

Causes of

death

Americas

Europe

Americas

Southeast

Asia

Africa

Eastern

Mediterranean

Infectious

disease

3.6

8.6

31.1

43.9

49.8

44.5

Cancer

21.5

18.1

9.0

4.4

2.9

4.2

Circulatory

diseases

54.5

53.8

24.5

15.6

11.7

14.1

Accidents

8.4

5.6

6.3

4.3

3.8

4.1

Table 18-1

In 1957, Heinz Fraenkel-Conrat and his coworkers were studying two viruses that infect tobacco plants. One of the disease-causing viruses was called TMV and the other, HRV. Both viruses were similar in structure. (See the diagrams in Figure 18-3.) It was easy to tell which virus had caused a disease because the lesions on the tobacco leaf differed, according to which virus was present. Fraenkel-Conrat knew that TMV and HRV are RNA viruses. He wanted to find out which part of the virusthe protein coat or the RNAwas carrying the genetic information needed to specify the reproduction of these viruses. He decided that he would find the answer by producing hybrids of the viruses. A hybrid has the RNA of one virus and the protein coat of another virus. In this case, the two hybrids are denoted H-T and T-H, where the first letter indicates the virus from which RNA was used.

Figure 18-3

167.What evidence in this experiment would show which part of the virus carried the genetic information? Refer to Figure 18-3.

168.What were the variables in the experiment? Refer to Figure 18-3.

169.What control would be used in this experiment? Refer to Figure 18-3.

170.Hypothesize what kind of lesions the T-H hybrid will cause. Explain. Refer to Figure 18-3.

171.In lesions caused by the H-T hybrid on tobacco leaves, the new viruses produced were not hybrids. They were all HRV. Why would this be so? Refer to Figure 18-3.

172.How might he determine whether the RNA or the protein coat of the H-T hybrid carried the genetic information of the virus? Refer to Figure 18-3.

173.Suggest how Fraenkel-Conrat might produce two hybrids. Refer to Figure 18-3.

174.How are water molds economically important?

175.How do cellular slime molds differ from plasmodial slime molds?

176.Describe the differences between protozoans and algae.

177.Imagine that you collect an organism from a pond. What characteristics of the organism would identify it as a protist?

178.What adaptation helps red algae to live in deep water?

179.What causes the dangerous red tide in the ocean?

180.Explain how diatoms reproduce?

181.How is almost every living thing directly or indirectly dependent on algae?

182.Euglenoids have characteristics of both autotrophs and heterotrophs. Explain.

183.How do protists differ from bacteria?

184.Why is the relationship between a termite and the flagellates that live in its intestine said to be mutualistic?

185.In the 1840s, a famine killed hundreds of thousands of people in Ireland. The famine was caused by a water mold that destroyed the entire potato crop. Hypothesize why the water mold was able to do such damage.

186.Anemia is a condition in which the blood is deficient in red blood cells and in hemoglobin. Why does a person with malaria develop anemia?

187.Table 19-1 shows a study of the protozoan populations per gram of leaf litter in a deciduous forest. What is your interpretation of the data?

Season

Ciliates

Testate Amoebas

Winter

1500/g

7000/g

Summer

400/g

700/g

Table 19-1

188.Ciliates have specialized cilia whose motion sweeps particles and/or bacteria into the oral groove. In an experiment, inert latex beads and bacteria of the same size were placed in the water with ciliated protozoans. Equal numbers of latex beads and bacteria were ingested by the protozoans. Form a hypothesis to explain these results.

It has been well documented that populations of protozoans increase when water is polluted. The presence of protozoans may simply indicate that these organisms feed on the bacteria, the active decomposers of organic matter in the water system. Imagine that you are working with a team of scientists to determine whether protozoans, like bacteria, have any beneficial effects on a water-purification system. The line at the top of the grid in Figure 19-1 shows the rate of decomposition of hay in water when bacteria are acting alone. The lower line shows the rate of decomposition when bacteria and mixed protozoans are present.

Figure 19-1

189.You have a vial of Carchesium polypinum, a species of ciliates found in wastewater. You have just read that these protozoans produce a kind of mucus, which they secrete into the water. You wish to develop a laboratory model of wastewater treatment. As your model, you drop some India ink into a beaker of tap water and add a vial of ciliates. What effect might the mucus produced by the Carchesium have on the India ink? How might you apply your results to the effect of mucus on waste matter in water? You can refer to Figure 19-1.

190.Suppose that very little of the waste matter disappeared in 50 days when protozoans were acting alone. Using Figure 19-1, what might you hypothesize then about the role of protozoans present with bacteria?

191.One member of the team hypothesizes that the protozoans are the decomposers in this case. Plan an experiment to prove whether or not this hypothesis is true. Refer to Figure 19-1 for your answer.

192.What happens to the same amount of waste when mixed protozoans are also present? Refer to Figure 19-1.

193.What does the graph in Figure 19-1 show about the amount of decomposition when bacteria work alone?

194.Compare and contrast basidium and basidiospore.

195.Compare and contrast hypha and mycelium.

196.Why is it important to make sure enough dirt is kept around the roots when transplanting a plant?

197.Differentiate between the four major phyla of fungi.

198.Describe what you think Earth would be like if there were no fungi to decompose dead materials.

199.Imagine that you discover an organism growing near the base of a tree in your yard. How could you determine whether the organism is a fungus?

200.Why are mycorrhiza economically important?

201.How is a zygospore formed?

202.How is reproduction in the deuteromycotes different from that in the other fungi?

203.How does the symbiotic relationship in a lichen benefit both organisms?

204.What are three different feeding relationships in which fungi are engaged?

205.How do fungi obtain nutrients? What is this process called?

206.A biologist proposes classifying fungi along with the protists, rather than as a separate kingdom. Why might this suggestion be accepted? Why might the suggestion be rejected?

207.Fossil plants often had mycorrhizal roots. How might the mycorrhizal association have played a role in the invasion of plants on land?

208.Hypothesize about how mycorrhizal associations may have evolved.

209.Wheat rust is a fungus that causes enormous damage to wheat crops. The life cycle of wheat rust alternates between two different hosts: wheat plants and barberry bushes. The rust needs both hosts to complete its sexual cycle. What could farmers do to eradicate the disease?

210.A soil fungus is one of the sources of cyclosporine. This drug is given to patients about to receive an organ transplant. Cyclosporine suppresses the body's natural response, which is to reject the organ transplant as a foreign substance. Hypothesize about how cyclosporine may be useful to the fungus that produces it.

To study the effect of mycorrhizal associations, one investigator grew six seedlings in nutrient solution. The seedlings illustrated in the drawing in Figure 20-1 were then placed in soil that contained no mycorrhizal fungi. The seedlings illustrated on the right were grown first in forest soil rich in mycorrhizal fungi and were then transferred to the soil without mycorrhizal fungi. All the plants grew for the same amount of time.

Figure 20-1

211.Plan an experiment to prove your hypothesis. Refer to Figure 20-1.

212.You have been given six healthy plants that were grown in soil with mycorrhizal fungi. Hypothesize what might happen to the mycorrhizae if you transplant the plants to soil that is phosphate rich. For your answer, refer to Figure 20-1.

213.Referring to Figure 20-1, what was the control in the investigation?

214.What was the variable in this investigation? See Figure 20-1.

At first, it may seem that the fungus receives the greatest benefit from a mycorrhizal association. After all, a plant can produce organic compounds that the fungus can use. However, the fungus is also useful to the plant. For one thing, the fungal hyphae increase the absorptive surface of the plant roots. Table 20-2 records the inflow of phosphate in two kinds of onion plantsmycorrhizal and non-mycorrhizal plants.

Inflow of Phosphate in Onion Plants

Interval

Duration

Inflow

(pmol/cm/s)

Trials

(days)

Mycorrhizal

Non-mycorrhizal

1

14

0.17

0.050

2

7

0.22

0.016

3

10

0.13

0.042

Averages:

0.17

0.036

Table 20-2

215.Why do mycorrhizal plants take in more phosphate than non-mycorrhizal plants? Refer to Table20-2.

216.In each of the trials recorded in Table 20-2, contrast the amount of phosphate that moved into an onion plant that is mycorrhizal with the phosphate in an onion plant that is non-mycorrhizal. What conclusion do you reach?

Problem

217.Complete the table of the characteristics of the six kingdoms in Table 17-1.

Character-

istic

Eubacteria

Archae-

bacteria

Protista

Fungi

Plantae

Animalia

cell type

prokary-

otic

body form

multi-

cellular

method of

obtaining

food

absorption,

photosyn-

thesis, or

chemosyn-

thesis

presence

of complex

organ

systems

no

Table 17-1

218.Complete Table 20-1.

Division of Fungi

Reproduce Sexually

Example of Fungi

Rhizopus

Mushrooms

Yeast

Penicillium

Table 20-1