Understanding Diversity: Systematics Understanding Diversity: Systematics LEARNING OBJECTIVES After studying this chapter in the text, the student should be able to: 1. State at least two justifications for the use of scientific names and classifications of organisms. 2. Arrange the Linnaean categories in hierarchical fashion, from most inclusive to least inclusive. 3. Describe the three domains and six kingdoms of organisms introduced in this chapter, and give the rationales for and against this system of classification. 4. Based on its distinguishing characters, classify an organism in the appropriate domain and kingdom. 5. Critically summarize the difficulties encountered in choosing taxonomic criteria. 6. Apply the concept of shared derived characteristics to the classification of organisms. 7. Identify methods of molecular biology now used by taxonomists, and summarize the advantages of molecular taxonomy. 8. Contrast monophyletic, paraphyletic, and polyphyletic taxa. 9. Compare and contrast two approaches to systematics: evolutionary systematics and phylogenetic systematics (cladistics). MULTIPLE CHOICE QUESTIONS 1. Humans depend on other organisms to provide all of the 1
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Understanding Diversity: Systematics
Understanding Diversity: Systematics
LEARNING OBJECTIVES
After studying this chapter in the text, the student should be able to:
1. State at least two justifications for the use of scientific names and classifications of organisms.
2. Arrange the Linnaean categories in hierarchical fashion, from most inclusive to least inclusive.
3. Describe the three domains and six kingdoms of organisms introduced in this chapter, and give the rationales for and against this system of classification.
4. Based on its distinguishing characters, classify an organism in the appropriate domain and kingdom.
5. Critically summarize the difficulties encountered in choosing taxonomic criteria.
6. Apply the concept of shared derived characteristics to the classification of organisms.
7. Identify methods of molecular biology now used by taxonomists, and summarize the advantages of molecular taxonomy.
8. Contrast monophyletic, paraphyletic, and polyphyletic taxa.
9. Compare and contrast two approaches to systematics: evolutionary systematics and phylogenetic systematics (cladistics).
MULTIPLE CHOICE QUESTIONS
1. Humans depend on other organisms to provide all of the following except:
*A. soil.*B. declining biodiversity.*C. pharmaceuticals.*D. a balance of CO2 and O2 in the atmosphere.*E. recycling of nutrients.
2. The worldwide variety of organisms and ecosystems is termed:
*A. making new biological species.*B. generating cladograms that represent evolutionary relationships
between organisms.*C. naming, describing, and classifying organisms.*D. conserving biodiversity.*E. comparing macromolecules to assess evolutionary relationships.
4. About __________ different species have been described and named to date.
*A. 160,000*B. 265,000*C. 750,000*D. 1.75 million*E. 6.25 million
5. The scientific study of the diversity of organisms and the evolutionary relationships between them is:
20, 21. Use the table to answer the corresponding questions.
Plantae Terrestrial, multicellular, photosynthetic organismsAnthophyta Vascular plants with flowers, fruits, and seedsMonocotyledones
Monocots. Flowering plants with one seed leaf (cotyledon) and flower parts in threes
Commelinales Monocots with reduced flower parts, elongated leaves, and dry 1-seeded fruits
Poaceae Grasses with hollow stems; fruit, a grain; and abundant endosperm in seed
Zea Tall annual grass with separate female and male flowersMays Only one species in genus - corn
20.Using the accompanying table, all of the following characteristics are used to establish the family level of classification for corn except:
*A. grasses with hollow stems.*B. fruit is a grain.*C. large endosperm in the seed.*D. one seed leaf.*E. None of the above, all are used to define the family level of
classification for corn.
21.Based on the information in the table, one characteristic used at the class level of classification for corn is:
*A. flower parts in fours or fives.*B. separate male and female flowers.*C. the presence of a single seed leaf.
29.Which of the following does not describe members of the Kingdom Fungi?
*A. absorb nutrients produced by other organisms*B. possess cell walls*C. not photosynthetic*D. cells lack a nucleus*E. yeasts and mushrooms
30.Fungi may be differentiated from plants, because fungi are:
*A. photosynthetic.*B. all macroscopic.*C. all multicellular.*D. heterotrophic.*E. all prokaryotic.
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Understanding Diversity: Systematics
31.Molecular evidence indicating less than 50% shared genes was the basis for:
*A. dividing the prokaryotes into two kingdoms, the Eubacteria and the Archaebacteria.
*B. separating the kingdom Protista from the kingdom Animalia.*C. including algae and slime molds in the kingdom Protista.*D. the separation of eukaryotes and prokaryotes.*E. placing fungi in a separate kingdom.
32.The evolutionary history of a group of organisms from a common ancestor is termed:
*A. biohistory.*B. phylogeny.*C. phrenology.*D. phenetics.*E. species origenetics.
33.An example of homologous structures is the wing of a bat and:
*A. the arm of a human.*B. the wing of a beetle.*C. the tail of a whale.*D. the leg of a chimpanzee.*E. the dorsal fin of a shark.
34.An example of homoplastic structures is the wing of a butterfly and:
*A. the wing of a moth.*B. the wing of a bird.*C. the antenna of the butterfly.*D. the legs of the butterfly.*E. the antenna of a moth.
35.Humans, as well as other mammals ranging from mice to elephants, have hair. Hair, then, would be considered to be:
*A. a derived character.*B. an ancestral character.*C. a cladistic character.*D. an analogous character.*E. a polyphyletic character.
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Understanding Diversity: Systematics
36.Sea snakes, which are reptiles, are similar in body form to eels, which are fish. Sea snakes and eels therefore share ________________ body form.
37.Homoplastic structures are a result of ________________ evolution.
*A. convergent*B. divergent*C. the absence of*D. multiphyletic*E. derived
38.Because whales breathe via lungs, have a little hair when born, and nurse their young, these _______________ characters allow us to classify them as mammals.
43.Comparison of the nucleotide sequences of a region of the genomes from the human, gorilla, and chimpanzee revealed that:
*A. humans are most closely related to the chimpanzee.*B. the common ancestor of the gorilla, chimpanzee, and human
diverged into 3 lines.*C. the chimpanzee is more closely related to the gorilla than the human.*D. the gorilla and chimpanzee have virtually identical sequences.*E. None of the above.
44.Comparison of ______________________ has been recently used to support the hypothesis that fungi are more closely related to animals than to plants.
*A. mitochondrial DNA sequences*B. mitochondrial tRNA sequences*C. ribosomal RNA sequences*D. ribosomal protein sequences*E. histone sequences
45.A study of the mitochondrial DNA of dog breeds around the world indicated that:
*A. all dogs appeared to develop from a mixture of wolf and coyote.*B. all dogs appeared to evolve from a mixture of the jackal and the wolf.
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Understanding Diversity: Systematics
*C. all dogs appeared to evolve from a mixture of the wolf, jackal, and the coyote.
*D. some dogs evolved from the coyote and some from the wolf.*E. all dogs appeared to evolve from a single origin from wolves.
46.Shared homologous structures would indicate that two taxa are:
*A. polyphyletic.*B. monophyletic. *C. outgroups.*D. in different clades.*E. homoplastic.
47.A taxon that includes all the descendants of an ancestor is called:
*A. known evolutionary relationships.*B. fossil evidence.*C. the number of shared characteristics.*D. the number of ancestral characteristics.*E. both ancestral and shared characteristics.
52.A cladist would attempt to classify organisms into ____________ taxa.
*A. some characteristics of both cladistics and phenetics.*B. only monophyletic groups.*C. only polyphyletic groups.*D. only derived characters.*E. only ancestral characters.
58.The scientist credited with developing the modern system of classification used today is:
*A. St. Augustine.*B. Aristotle.*C. Cavalier-Smith.*D. Woese.*E. Linnaeus.
59-61. Use the figure to answer the corresponding questions.
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Understanding Diversity: Systematics
59.The organism labeled B in the accompanying figure is a common ancestor to:
*A. organism 2.*B. organism 3.*C. organism 5.*D. organism 6.*E. All of the above.
60. In the accompanying figure, the pair of organisms that have the most recent ancestor is:
*A. 2 and 4.*B. 6 and 4.*C. 4 and 5.*D. 2 and 3.*E. 1 and 2.
61. In the accompanying figure, the taxon labeled II is:
*A. monophyletic.*B. paraphyletic.*C. polyphyletic.*D. a clade.*E. an outgroup.
SHORT ANSWER QUESTIONS
Arrange the Linnaean categories in hierarchical fashion, from most inclusive to least inclusive, starting at the level of domain. BONUS: Insert the appropriate names for each category for a particular organism, such as corn or humans. Partial credit will be given.
Identify and briefly discuss two difficulties encountered in choosing taxonomic criteria. Use specific examples in your discussion.
Contrast the following terms: monophyletic, paraphyletic, and polyphyletic. Provide one example for each.
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Understanding Diversity: Systematics
DISCUSSION OR THOUGHT QUESTIONS
1. Construct a table with the six kingdoms listed. Identify several members of each kingdom, as well as diagnostic features of each kingdom.
Concepts to Consider: kingdom Plantae — eukaryotic, mostly photosynthetic, complex reproductive structures, cell walls of cellulose, the plants; kingdom Animalia — eukaryotic, heterotrophic, mostly multicellular, usually with nervous tissues, motile, the animals; kingdom Fungi — eukaryotic, heterotrophic, mostly multicellular, bodies formed by hyphae, cell walls of chitin; kingdom Protists — eukaryotic, photosynthetic or heterotrophic, many are unicellular, many are motile; kingdom Eubacteria — prokaryotic, varied metabolism, may be pathogenic, cell wall of peptidoglycan in most, the bacteria; kingdom Archaebacteria — the bacteria adapted to live in unusual habitats, including the methanogens, halophiles, and extreme thermophiles, cell walls without peptidoglycan.
2. A new species of beetle is discovered. If you were a cladist, what steps might you take to classify this beetle? How might this approach be different if you were a pheneticist?
Concepts to Consider: Cladists study shared and ancestral characters and attempt to identify outgroups; pheneticists use a numerical approach and quantify shared characteristics to determine taxonomic classification.
3. Describe the biological basis of the species taxon. If there were not humans on earth to classify organisms, would species still exist?
Concepts to Consider: Taxonomy is based on evolutionary relationships; the species concept is based on reproductive isolation and is therefore a biological premise. Species would exist whether we are here to name them or not; other taxa are also based on evolutionary ties, at least by cladists and systematists using the classic evolutionary approach.
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Viruses and Prokaryotes
Viruses and Prokaryotes
LEARNING OBJECTIVES
After studying this chapter in the text, the student should be able to:
1. Describe the structure of a virus and compare a virus with a free-living cell.
2. Trace the evolutionary origin of viruses according to current hypotheses.
3. Characterize bacteriophages and contrast a lytic cycle with a lysogenic cycle.
4. Explain how viruses infect animal and plant cells.
5. Describe the reproductive cycle of a retrovirus such as human immunodeficiency virus.
6. Compare and contrast viroids and prions.
7. Describe the structure and common shapes of prokaryotic cells.
8. Describe asexual reproduction in prokaryotes and summarize three mechanisms (transformation, conjugation, and transduction) that may lead to genetic recombination.
9. Characterize the metabolic diversity of autotrophic and heterotrophic prokaryotes, including aerobes, facultative anaerobes, and obligate anaerobes.
10. Compare the three domains: Eubacteria, Archaea, and Eukarya.
11. Distinguish among the three main groups of archaea and among several groups of eubacteria as described in Table 23–3. Give examples of each group.
12. Discuss the ecological roles of prokaryotes, their importance as pathogens, and their commercial importance.
MULTIPLE CHOICE QUESTIONS
1. Many microscopic organisms or entities have been identified as pathogens, including all of the following except:
*A. protozoa.*B. viruses.*C. fungi.*D. bacteria.*E. None of the above, all may be pathogenic.
2. Which of the following statements about bacteria is false?
*A. A small percentage of bacteria are pathogenic.
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Viruses and Prokaryotes
*B. Some bacteria can photosynthesize.*C. Bacteria are important decomposers.*D. Bacteria are not cellular and are sometimes not classified as life forms.*E. Bacteria convert atmospheric nitrogen into ammonia and then nitrates that
can be used by plants.
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Viruses and Prokaryotes
3. Viruses were first identified:
*A. because they caused an infection and formed colonies on nutrient agar plates.
*B. because they were seen in the light microscope.*C. because they caused an infection and were small enough to pass through
filters that trapped bacteria.*D. because they were smaller than bacteria and had all the properties of living
organisms.*E. because they caused an infection and were seen in the electron
6, 7. Use the figure to answer the corresponding questions.
6. The structure of the virus in the accompanying figure that is common to all viruses is:
*A. 2.*B. 3.*C. 4.*D. 5.*E. All of the above.
7. The function of the structure labeled 3 is:
*A. attachment to a host cell.*B. locomotion.
*C. mate recognition.*D. replication.*E. to take over host cell
mechanisms.
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Viruses and Prokaryotes
8. Viruses are classified by:
*A. the sequence of their DNA.*B. structural similarities.*C. the sequence of their rRNA genes.*D. the traditional Linnaean binomial nomenclature system.*E. an international committee.
9. Viruses:
*A. are very tiny cells on the order of 500 nm.*B. contain both RNA and DNA.*C. cannot independently perform metabolic activities.*D. have a standard morphology that includes a capsid, tail, and tail fibers.*E. All of the above.
10.Viruses:
*A. are usually species-specific.*B. may have multiple origins.*C. are probably related to mobile genetic elements.*D. may have escaped from cells.*E. All of the above.
11.Phages are being considered for:
*A. vectors in gene therapy experiments.*B. antibiotics in bacterial infections.*C. gene transfer vectors in animal cells.*D. being equivalent to the first living organisms.
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Viruses and Prokaryotes
*E. All of the above.
12.Temperate viruses:
*A. always destroy their host immediately.*B. are considered virulent.*C. do not always destroy their host.*D. do not undergo a lysogenic cycle.*E. undergo a lytic cycle.
13.Virulent (lytic) phages:
*A. infect viruses.*B. destroy bacteria.*C. infect, but do not destroy bacteria.*D. infect virions.*E. infect prions.
14.The five stages of a lytic infection are attachment, penetration, _____________, assembly, and release.
*A. is phage DNA that is integrated into viral DNA.*B. is phage DNA that is integrated into bacterial DNA.*C. replicates only when the eukaryotic cell it infects replicates.*D. is an underdeveloped lytic virus.*E. is a bacterial cell about to lyse.
16.The bacterium that causes botulism disease is harmless until it:
*A. is infected by lytic bacteria.*B. is infected by certain retroviruses.*C. contains a certain prophage DNA.*D. is irradiated by UV radiation.*E. is infected by prions.
17.____________ conversion occurs when a bacterium carrying viral genes takes on new, atypical characteristics.
*A. having reverse transcriptase instead of RNA-dependent RNA polymerase.*B. the shape of their capsid.*C. the way they infect their host cells.*D. the sugar coating on their capsids.*E. lytically destroying their hosts.
20.Which of the following diseases is not caused by a virus?
*A. rabies*B. polio*C. warts in humans*D. chickenpox*E. Lyme disease
21.Which of the following identifies a group of DNA viruses?
24.Human viruses can enter human cells by fusion with the cell membrane or by:
*A. diffusion into the cell.*B. passage through specific protein channels.*C. coating themselves with lipids that cloak their entrance into the cell.*D. endocytosis.*E. hitchhiking onto protein signals entering the cell.
25.Viroids cause a variety of plant diseases and are composed only of:
*A. strands of RNA.*B. strands of DNA.*C. protein coats.*D. peptidoglycan.*E. a capsid.
26.Mad cow disease is an example of an infection caused by a:
27._____________ is credited with the discovery of prions as a new biological principle of infection.
*A. Stanley Prusiner*B. Anton van Leeuwenhoek*C. Dmitrii Ivanowsky*D. Stanley Brenner*E. Carl Woese
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Viruses and Prokaryotes
28.A symptom of a transmissible spongiform encephalopathy (TSE) is:
*A. degeneration of the digestive tract.*B. progressive immune deficiency.*C. degeneration of the brain and central nervous system.*D. inflammation of the reproductive organs.*E. influenza-like symptoms.
29.The volume of a typical bacterium is about ____________ the volume of a typical eukaryotic cell.
*A. equal to*B. a half*C. a tenth*D. a hundredth*E. a thousandth
32, 33. Use the figure to answer the corresponding questions.
32.The structure in the accompanying figure labeled C is:
*A. a ribosome.*B. the plasma membrane.*C. the capsule.*D. the cell wall.*E. the flagellum.
33.What is the function of the structure labeled A in the accompanying figure?
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Viruses and Prokaryotes
*A. to adhere to surfaces or other bacteria*B. to prevent phagocytosis*C. support and protection in hypotonic conditions*D. transmission of DNA between bacteria*E. locomotion
34.Even though bacteria lack membrane-bound organelles, such as chloroplasts and mitochondria, they can still perform the functions of these organelles by localizing certain metabolic enzymes on:
*A. the nuclear membranes.*B. the endoplasmic reticulum.*C. the plasma membrane.*D. ribosomes.*E. the cell wall.
35.Most bacterial cells keep from bursting in a hypotonic environment by:
*A. an efficient water pump.*B. a tough cell membrane.*C. pumping large quantities of salts into the cell.*D. a rigid cell wall.*E. a stiff capsule.
36.Gram-positive bacteria would stain __________ in a gram stain because of a thick layer of __________ in their cell walls.
37.The walls of Eubacteria contain peptidoglycan, which is:
*A. lipids crosslinked with sugars.*B. sugars crosslinked with proteins.*C. a protein.*D. a lipid.*E. a polysaccharide.
38.Penicillin works most effectively against gram-positive bacteria because:
*A. penicillin affects cell membranes.
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Viruses and Prokaryotes
*B. they have a thick peptidoglycan cell wall and penicillin affects the synthesis of peptidoglycans.
*C. they have special protein channels that allow penicillin to enter the cell and halt the cell cycle.
*D. they are smaller than gram-negative bacteria and, thus, easily take up penicillin by diffusion.
*E. they contain prophages that negatively interact with penicillin.
39.Some bacteria avoid a host’s immune system by means of:
*A. efficient use of their flagella.*B. ameboid motion.*C. their capsule.*D. changing their cell wall structure.*E. eliminating the use of a membrane.
40.Bacteria:
*A. are incapable of locomotion.*B. move by means of pili *C. move by means of cilia.*D. move by means of a rotating flagella.*E. move by means of a whiplike flagella.
41.Small circles of DNA called ______________ exist in addition to the bacterial chromosome.
44.Pili are involved in adhesion of bacterial cells to a substrate or host, or in transmission of __________ between bacteria.
*A. ribosomes*B. cytoplasm*C. vectors*D. RNA*E. DNA
45.Prokaryotes have their genetic information stored in:
*A. several small, circular pieces of DNA.*B. a single, small, circular piece of DNA.*C. a large, linear piece of DNA.*D. several small, linear pieces of DNA.*E. a large, circular piece of DNA.
46._______________ is a form of genetic exchange in bacteria that involves contact between two cells.
52.The first indication that Archae were different from the Eubacteria came from differences noted in their:
*A. cell wall.*B. preferred habitats.*C. 16 S rRNA sequence.*D. protein synthesis machinery.*E. resistance to antibiotics.
53.The Archaea differ from the Eubacteria and eukaryotes by having different ____________ in their cell membranes, but they are similar to eukaryotes in their ____________ process.
54, 55. Use the figure to answer the corresponding questions.
54.Which of the following groups from the accompanying figure represents gram-negative bacteria?
*A. Spirochetes*B. Protists*C. Methanogens*D. Halophiles*E. None of the above.
55.Which of the following groups from the accompanying figure is a member of the Eubacteria domain?
*A. Fungi*B. Halophiles*C. Chlamydias*D. Protists*E. More than one of the above.
56.About how many different species of bacteria have been classified?
*A. 200*B. 2,000*C. 4,000*D. 20,000*E. 40,000
57.The most significant difference between the Archaea and the Eubacteria is:
*A. lack of a nuclear envelope in the Archaea.*B. the absence of the 70S ribosomes in the Eubacteria.*C. the presence of a single filament flagellum in the Eubacteria.*D. the absence of peptidoglycans in the cell walls of the Archaea.*E. All of the above.
58.One difference between the Archaea and the Eukarya is:
*A. the lack of a nuclear envelope in the Archaea.*B. the absence of the 70S ribosomes in the Archaea.*C. the presence of membrane-bound organelles in the Archaea.*D. the presence of peptidoglycans in the cell walls of the Archaea.
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Viruses and Prokaryotes
*E. the presence of simple RNA polymerase in the Archaea.
59.One unique characteristic associated with some of the extreme halophilic Archaea is:
*A. that they are found at deep-sea vents on the sea floor.*B. that they are a source of most known antibiotics.*C. that they have photosynthetic ability involving a purple bacteriorhodopsin
pigment.*D. that they fix atmospheric nitrogen that is then used by plants.*E. that most form symbiotic associations.
60._____________ Archae are typically found in abnormally hot environments.
*A. Extreme halophile*B. Extreme thermophile*C. Pyrrhanogen*D. Metanogen*E. Any of the above.
63.The bacterial reproductive parasite Wolbachia is known to:
*A. eradicate males from a population.*B. convert males into females.*C. cause infected females to lay eggs that develop without fertilization.*D. reduce the number of males in a population.*E. All the above.
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Viruses and Prokaryotes
64.The symbiotic bacteria found in the root nodules of legumes:
*A. supply the plant with the nitrogen it needs in the form of nitrates.*B. are motile, soil-dwelling bacteria.*C. belong to the genus Rhizobium.*D. are gram-negative Eubacteria.*E. All of the above.
65.Koch’s postulates include all the following except:
*A. when a sample of a pure culture is injected into a healthy host causes the same disease.
*B. a sample of the microorganism from a diseased host can be grown in pure culture.
*C. the microorganism can be recovered from an experimentally infected host.*D. the microorganism must be visible in the electron microscope.*E. the pathogen must be present in every individual with the disease.
66.The first bacteria that was clearly identified as the cause of an infectious disease was:
*A. Legionella pneumophila, which causes Legionnaires’ disease.*B. Chamydia sp., which causes pelvic inflammatory disease in women.*C. Clostridium botulinum, which causes botulism.*D. Vibrio cholerae, which causes cholera.*E. Bacillus anthracis, which causes anthrax.
SHORT ANSWER QUESTIONS
1. Compare and contrast a virus and a bacterium.
List the characteristics of the following groups and identify examples for each: Archaea, Eubacteria, and Eukarya.
Compare and contrast the metabolic diversity of bacteria in one of the two groups below.
A. Obligate anaerobes, facultative anaerobes, and aerobesB. Autotrophic and heterotrophic bacteria
Identify and briefly discuss two ecological roles filled by bacteria.
DISCUSSION OR THOUGHT QUESTIONS
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Viruses and Prokaryotes
1. Describe the theory that attempts to explain the species specificity of viruses to their hosts.
Concepts to Consider: Viruses may have come about by escaping from cellular organisms such as bacteria, plants, and animals. It may be that viruses can only infect organisms from which they originated. This could explain why viruses are very specialized concerning their hosts.
2. Discuss the distinction between gram-negative and gram-positive bacteria. In the laboratory, how is this determined? What are differences between these two groups of bacteria?
Concepts to Consider: Gram-positive bacteria are those that absorb and retain crystal violet, a violet pigment that shows under a microscope. Gram-negative do not retain this pigment and, therefore, appear red. This effect is due to the fact that gram-positive bacteria have very thick peptidoglycan cell walls, which absorb and retain the crystal violet pigment. Gram-negative bacteria do not have thick cell walls and, therefore, do not retain the pigment very well. The differences in the cell walls between gram-positive and gram-negative bacteria have a bearing on how certain drugs affects these two bacterial types. Gram-positive bacteria are very susceptible to penicillin because their cell walls are weakened by the drug. Gram-negative bacteria are not easily harmed by penicillin. As a result, gram-negative bacteria are much harder to control.
3. Describe endotoxins and exotoxins. What effects do they each have on infected persons?
Concepts to Consider: Endotoxins are toxins that are released from bacteria after they have died or lysed. These toxins are a component of the bacterial cell wall or the internal environment and cause systemic symptoms such as fever and edema. Exotoxins are those released into the environment (host) by living bacteria. They result in a very broad range of toxin-specific symptoms.
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The Protists
The Protists
LEARNING OBJECTIVES
After studying this chapter in the text, the student should be able to:
1. Characterize the features common to the members of kingdom Protista.
2. Discuss in general terms the diversity inherent in the protist kingdom, including means of locomotion, modes of nutrition, interactions with other organisms, habitats, and modes of reproduction.
3. Discuss the endosymbiont theory, and briefly explain some of the evidence that supports it.
4. Describe the kinds of data biologists use to classify eukaryotes.
5. Explain why zooflagellates are no longer classified in a single phylum, and distinguish among diplomonads, euglenoids, and choanoflagellates.
6. Briefly describe and compare the following alveolates: ciliates, dinoflagellates, and apicomplexans.
7. Briefly describe and compare the following heterokonts: water molds, diatoms, golden algae, and brown algae.
8. Describe the foraminiferans and actinopods, and explain why many biologists classify them in the monophyletic group Cercozoa.
9. Support the hypothesis that red algae and green algae are a monophyletic group with land plants.
10. Briefly describe and compare the following Amoebozoa: amoebas, plasmodial slime molds, and cellular slime molds.
27.All of the following statements about the phylum Phaeophyta are true except:
*A. this group includes the most complex algae that have blades, stipes, and holdfasts.
*B. they share a common ancestor with representatives of the plant kingdom.*C. they represent the largest members of the kingdom Protista.*D. they are harvested for algin, which is used in a variety of commercial
products.*E. they are ecologically important as producers and in providing habitats along
rocky coastlines.
28.Of the following algae, which phylum exhibits the most diverse morphology, forming unicells, filaments, and sheets?
30.Green algae exhibit alternation of generations and varied sexual reproduction. When their sexual reproduction involves the fusion of flagellated gametes of different sizes, it is known as:
42.The ____________ are zooflagellates that are very primitive and may give biologists clues as to the evolutionary relationships between the prokaryotes and the protists.
*A. cryptomonads*B. chrysophytes*C. diplomonads*D. water molds*E. slime molds
43.Protists may move by pushing out their cytoplasmic extensions, known as:
50.Backpackers’ diarrhea, a common infection among campers and hikers, particularly in the mountains of the western United States, is caused by _________________.
56. In ciliates macronuclei controls ____________________________.
*A. reproduction*B. growth*C. metabolism*D. movement*E. Both B and C.
57.The symbiotic dinoflagellates, which live in the bodies of marine invertebrates such as mollusks, jellyfish, and corals, are called __________________________.
*A. Zooxanthellae*B. apicomplexans*C. sporozites*D. ciliates*E. None of the above.
58.Dinoflagellates that contribute substantially to the productivity of coral reefs are ____________.
*A. Zooxanthellae*B. apicomplexans*C. sporozites*D. ciliates*E. None of the above.
59.Water molds are members of the kingdom___________________.
*A. Protists*B. Fungi*C. Plantae*D. Eubacteria*E. Animalia
1. Identify the modes of nutrition found in members of the kingdom Protista and include two examples of each.
Compare and contrast the following representatives of the kingdom Protista.A. green algae and euglenoidsB. apicomplexans and dinoflagellatesC. cellular slime molds and amoeba
Discuss the structures that allow motility in the following phyla: Rhizopoda, Alveolata, and Ciliophora.
Discuss the commercial significance of protests.
Watermolds continue to cause problems in commercial crop production. Discuss.
DISCUSSION OR THOUGHT QUESTIONS
1. List several diseases caused by protozoa. Include the causal organism, the phylum in which it is classified, and when possible, its means of transmission.
Concepts to Consider: Rhizopoda — Entamoeba histolytica, amoebic dysentery, transmitted via contaminated water; Acanthamoeba causes infections in contact lens users. Zoomastigina — Trypanosoma causes African sleeping sickness, transmitted via tsetse flies; Giardia intestinalis causes backpackers'
diarrhea, transmitted via contaminated water. Apicomplexa — Plasmodium causes malaria; transmitted via a mosquito. Dinoflagellata — various species cause paralytic shellfish poisoning and other neurological disorders.
2. Discuss the ecological significance of dinoflagellates.
Concepts to Consider: symbiotic dinoflagellates; population explosions (blooms) of dinoflagellates, known as red tides, may cause fish kills and paralytic shellfish poisoning in humans. A newly discovered dinoflagellate, Pfiesteria, has been shown to cause massive fish kills; exposure to this dinoflagellate has had serious consequences to humans as well.
3. Discuss the uncertainties and available evidence related to the evolutionary relationships among the photosynthetic protists and also in how they relate to the plants.
Concepts to Consider: consult Figure 24.1; also need to examine pigment composition, storage molecules, cell wall composition, and molecular data.