Questions and Answers of Biology Concepts Investigations

Compare the defining features of flatworms to those of other protostomes and deuterostomes. What features are similar among these groups? What features are different?
Using the evolutionary trees in this chapter, compare cnidarians to sponges and to the clade containing flatworms, mollusks, and annelids.
Like sponges, plants are sessile organisms, but plants and sponges have dissimilar appearances. What important difference between sponges and plants explains this observation?
Analyze the evolutionary tree in figure 21.2, and then write an argument supporting or refuting this statement: Annelids are more closely related to flatworms than to roundworms.Figure 21.2
Distinguish between(a) Radial and bilateral symmetry;(b) Blastula and gastrula;(c) Direct and indirect development;(d) Complete and incomplete digestive tracts;(e) Coelom and pseudocoelom.
List the criteria used to distinguish(a) Animals from other organisms;(b) Vertebrates from invertebrates;(c) Protostomes from deuterostomes;(d) Ectotherms from endotherms.
Suppose you watch a video showing the development of an unknown animal. What clues can the developmental pattern give you about how this organism is classified? Creating a flow chart might be useful.
Compare the nine major animal phyla in the order in which the chapter presents them, listing the features for each group.
Create a graph showing the number of species in each group of fungi. Which group is least diverse? Based on the habitats and reproductive structures of these fungi, propose an explanation for their
White nose syndrome is an illness that weakens and kills bats roosting in caves. Affected animals have a white fungus around their muzzle and on their wings, but no one knows if the fungus causes the
Why might it be challenging to produce drugs that treat fungal infections without harming human cells?
Describe how experiments might show thata. chytrids are killing amphibians.b. fungi benefit more from a lichen relationship than do algae.c. bacteria help leaf-cutting ants cultivate one fungus while
Use the Internet to find examples of chytrids, zygomycetes, ascomycetes, and basidiomycetes that cause diseases in plants or animals. How does each fungus infect a host and spread to new hosts? What
Compare and contrast endophytes, mycorrhizae, and lichens.
List some places where you might find ascomycetes.
Each ascus within an ascomycete fruiting body contains eight cells. Are these cells haploid, diploid, or dikaryotic? Is every cell within an ascus genetically unique? What is the fate of each cell?
Other than shared DNA sequences, what characteristics place ascomycetes and basidiomycetes together as sister groups?
Describe the difference between sexual and asexual reproduction in zygomycetes. Why might asexual reproduction be more common than sexual reproduction?
Does the absence of fuzzy mold on bread mean that it is free of fungi? Why or why not?
Create a table with three columns. Write the following terms in the first column: mycelium, zygospore, basidium, conidium, and hyphae. Define the terms in the second column, and classify the terms as
Sketch each of the following structures: mycelium; ascus with ascospores; zoospore; zygospore; basidium with basidiospores.
Review figure 19.5, which shows the alternation of generations in plants. Compare and contrast the life cycles of zygomycetes, ascomycetes, and basidiomycetes with the basic plant life cycle.Figure
Many fungi produce chemicals that inhibit bacterial growth. Why might the genes encoding these chemicals be adaptive to fungi?
What characteristics distinguish each phylum of fungi?
In figure 20.5, which groups of fungi are monophyletic? What term can you use to describe the other groups?Figure 20.5 Dikaryotic cells Basidiomycota Basidium with basidiospores Ascomycota Ascus with
Review figure 20.5. Are fungi more closely related to animals or to plants? What characteristics do fungi share with plants? What characteristics do fungi share with animals? Dikaryotic cells
Fungi and animals are both heterotrophs. What does this mean? How do fungi and animals differ in how they obtain food?
Refer to figure 20.25 and the chapter content to answer the following questions.1. Review the Survey the Landscape figure in the chapter introduction, and add eukaryotes, animals, plants, protists,
Give examples of fungi that are important economically, ecologically, and as food for humans.
What are the pros and cons of pursuing biofuels as alternatives to fossil fuels? In your opinion, do the pros outweigh the cons, or vice versa? Justify your answer.
Human activities and natural phenomena can drive plant species to extinction. The U.S. Department of Agriculture Natural Resources Conservation Service maintains lists of threatened and endangered
Suppose you and a friend are hiking and you see an unfamiliar plant. What observations would you make in trying to determine which type of plant it is?
A slight change in a plant species’ flower structure might favor a different pollinator. How might such a change in flower structure lead to a new plant species? How does coevolution between
Compare and contrast the life cycles of the four groups of plants. How does each group represent a variation on the common theme of alternation of generations?
In a sentence or two, either support or refute the following statement: The pollen grains of angiosperms are homologous to the spores of bryophytes.
An angiosperm called “ghost plant” does not produce chlorophyll or other photosynthetic pigments and is almost completely white. Based only on this information, what assumptions can you make
The spurge-laurel is a species of shrub. It produces berries that, if consumed, will cause internal bleeding and death in humans. On the other hand, some birds can eat the berries and remain
Scientists have studied plant populations that have moved into areas with low herbivory compared to the plant’s previous habitat. After many generations in the new habitat, the plants produce fewer
The immature fruit of the opium poppy produces many chemicals that affect animal nervous systems. In what way might these chemicals benefit the plant?
Describe how the petals, ovary, and ovule of flowers participate in reproduction. What happens to each part after fertilization?
Your friend John is admiring what he calls “little flowers” on a moss. How would you correct his statement? In what way might those structures be similar to flowers?
How do the adaptations of gymnosperms and angiosperms enable them to live in drier habitats than bryophytes and seedless vascular plants?
A fern plant can produce as many as 50 million spores a year.(a) How are these spores similar to and different from seeds?(b) In a fern population that is neither shrinking nor growing, approximately
Give at least two explanations for the observation that bryophytes are much smaller than most vascular plants. How can increased height be adaptive? In what circumstances is small size adaptive?
List the characteristics that distinguish the four major groups of plants; then provide an example of a plant within each group.
How are terrestrial habitats different from aquatic habitats? List the adaptations that enable land plants to obtain resources, transport materials, and reproduce; explain how each adaptation
Analyze the alternation of generations common to all plants. If you analyzed the DNA of all of the gametes produced by one gametophyte, would you see variation among the gametes?
Refer to figure 19.21 and the chapter content to answer the following questions.1. Review the kingdoms within domain Eukarya, using the Survey the Landscape figure in the chapter introduction. To
What characteristics do all land plants have in common?
Suppose someone hands you a microscope and a single-celled organism. Create a flow chart that you could use to identify the specimen.
Give three examples of protists for which the classifications have recently changed. In each case, what was the justification for the old category, and what is the justification for the change?
Why might overwatering your plants make them more susceptible to infection by some kinds of heterotrophic protists?
Natural selection favors stalk formation in cellular slime molds even though the cells of the stalk die. Explain this observation.
How is it adaptive for a red alga to have pigments other than chlorophyll?
How are kelp similar to trees? How are they different?
Explain why the fossil record for diatoms is much more complete than that of other protists, such as amoebae and slime molds.
The amoeba Pelomyxa palustris is a single-celled eukaryote with no mitochondria, but it contains symbiotic bacteria that can live in the presence of oxygen. How does this observation support the
Describe the relationship between nutrient pollution and harmful algal blooms. Why might harmful algal blooms be more frequent in summer? What steps could coastal communities take to prevent nutrient
Refer to figure 18.22 and the chapter content to answer the following questions.1. Review the Survey the Landscape figure in the chapter introduction, and then add evolution, domain Eukarya, plants,
Explain why evolutionary biologists are interested in choanoflagellates, green algae, and organisms with mitochondria whose genomes resemble those of bacteria.
Mycobacterium tuberculosis causes most cases of tuberculosis. Strains of this bacterium that are resistant to all known antibiotics have become increasingly common. Explain how this change occurred;
After treatment with antibiotics, your belly aches. Why might taking antibiotics cause digestive problems? How might the problem fix itself?
Botox is a toxin produced by the bacterium Clostridium botulinum. When ingested with tainted food, Botox can kill by paralyzing muscles needed for breathing and heartbeat. Physicians inject small
How is a biological virus similar to and different from a computer virus?
Rhinoviruses replicate in the mucus-producing cells in a person’s nose, throat, and lungs, causing the common cold. Papillomaviruses, which infect skin cells, cause growths called warts. HIV
Your biology lab instructor gives you a petri dish of agar covered with visible colonies. Your lab partner says the colonies are viruses, but you disagree. How do you know the colonies are bacteria?
Compare today’s changing culture to biological evolution by means of natural selection. How are they similar? How are they different? Can you think of examples of knowledge, beliefs, and behaviors
Suppose that gene A does not affect fitness in a small population of earthworms contained in a glass enclosure. For 20 worm generations, a pair of curious scientists study the frequencies of the A
The video game “Spore” invites players to design creatures and guide them through “five stages of evolution.” Search the Internet for information about “Spore”; describe how evolution in
Describe the basic parts of a virus and how each contributes to viral replication.
Refer to figure 16.12 and the chapter content to answer the following questions.1. Review the Survey the Landscape figure in the chapter introduction to recall what types of organisms viruses infect.
Why is it inaccurate to refer to the “growth” of viruses?
Why are lytic viruses better suited as agents of “phage therapy” than are lysogenic viruses? How would you test whether such a treatment would be effective? Would you be willing to take a
As described in this chapter’s Burning Question, human papillomavirus (HPV) infects cells of the skin and genitals, but it has never been shown to infect T cells. If a researcher put HPV and T
Refer to figure 16.B; then explain why a mutation in a gene encoding a T cell coreceptor might be beneficial.Figure 16.B T cell with coreceptor: T cell without coreceptor: HIV can infect no HIV
Search the Internet for information about the injectable flu vaccine (a “flu shot”). Why is the flu shot administered annually, when many other vaccines last for years? Is it possible for a flu
Kuru is a prion disease associated with cannibalism in humans. Using your knowledge about prions, why might eating other members of the same species make prion diseases more likely to occur? What can
Why do antibiotics kill bacteria but leave viruses unharmed?
Use the Internet to find three examples of viruses that infect humans but are not mentioned in the chapter. Describe the symptoms associated with each infection.
Explain why the antibiotics penicillin and polymyxin are not effective against archaea. (Review this chapter’s Apply It Now box.)
Refer to figure 17.18 and the chapter content to answer the following questions.1. Review the Survey the Landscape figure in the chapter introduction, and connect viruses and evolution to the Pull It
Why do some microbiologists disagree with classifying bacteria and archaea as “prokaryotes”?
Give five examples that illustrate how bacteria and archaea are important to other types of organisms.
If you were developing a new “broad-spectrum” antibiotic to kill a wide variety of bacteria, which cell structures and pathways would you target? Which of those targets also occur in eukaryotic
Describe your own metabolic classification: Are you a photoautotroph, photoheterotroph, chemoautotroph, or chemoheterotroph? Are you an obligate aerobe, an obligate anaerobe, or a facultative
A prokaryote with which type of metabolism would be especially challenging to isolate and culture? Explain your answer. Refer to section 17.2B.
Ernst Mayr defined a biological species as a population whose members can exchange genetic material during reproduction. How does horizontal gene transfer complicate this definition of species?
Why did the discovery of archaea generate interest in searching for cells on other planets?
In an article in Nature magazine, Sean Nee wrote about the diversity of species on Earth: “Earth’s real biodiversity is invisible, whether we like it or not.” What does that statement mean?
Ecosystems rely on nitrogen-fixing bacteria, which convert atmospheric nitrogen (N2) into ammonium (NH4+). Into what types of organic molecules do plants incorporate the nitrogen in ammonia?
Stomach ulcers, once thought to be entirely a product of spicy food or high stress, are now known to be caused by bacteria (Helicobacter pylori). How has ulcer treatment changed because of this new
Use the Internet to learn about sexually transmitted diseases (STDs). Which of the most common STDs are caused by bacteria? Choose one STD caused by bacteria to study in more depth; describe how the
Probiotics are dietary supplements consisting of live bacteria that are normally found in the human digestive tract. Some people claim that consuming probiotics promotes digestive health. Design an
In what ways has culture been an important factor in human evolution?
Use the Internet to learn about National Geographic’s Genographic Project. What are the main objectives and components of the project, and how are researchers using the information they gather to
How do you predict a scientist would respond to a question about whether humans “evolved from monkeys”?
What can scientists learn by comparing the fossilized skeletons of extinct primates with the bones of modern species?
Explain how opposable thumbs, large brains, and binocular vision are adaptive to primates.
Distinguish among the terms primate, hominid, hominin, and Homo.
How has the emergence of new species changed Earth’s history?

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