BIOL 1407 Exam 1 Ch. 26-34

In onions (Allium), cells of the sporophyte have 16 chromosomes within each nucleus. Match the number of chromosomes present in each of the following onion tissues. How many chromosomes should be in a generative cell nucleus?

8

The figure depicts the outline of a large fairy ring that has appeared overnight in an open meadow, as viewed from above. The fairy ring represents the furthest advance of this mycelium through the soil. Locations AD are all 0.5 meters below the soil surface. Responses may be used once, more than once, or not at all. At which location is the mycelium currently absorbing the most nutrients per unit surface area, per unit time?

A

Which of the following taxonomic groups is the most successful?

All extant species are successful, based on their continuing existence.

Which of the following statements is supported by the phylogeny in the figure?

Animals with extremely different adult forms can be relatively closely related.

"Rare events" can help us understand evolutionary events, as shown in the figure. Which of the following statements explains the logic of this approach?

Because the mutation likely occurred only once, all organisms with the mutation have a common ancestor with the mutation.

Canadian and Swiss researchers wanted to know if the diversity of arbuscular mycorrhizal fungi (AMF) was important to the productivity of grasslands (M.G.A. van der Heijden, J. N. Klironomos, M. Ursic, P. Moutoglis, R. Streitwolf-Engel, T. Boler, A. Wiemken, and I. R. Sanders. 1998. Mycorrhizal fungal diversity determines plant biodiversity, ecosystem variability and productivity. Nature 396:69-72). Specifically, they wanted to know if it mattered which specific AMF species were present, or just that some type of AMF was present. They grew various plants in combination with one of four AMF species (A, B, C, & D), no AMF species (O), or all four AMF species together (A+B+C+D), and they measured plant growth under each set of conditions. All plant species were grown in each plot, so they always competed with each other with the only difference being which AMF species were present.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. Graph (e) is the total biomass (grams) of all 11 plant species combined, graph (f) is the biomass of Bromus erectus plants only, separated from the total.19) What is the major difference between Bromus erectus (graph f) and the other plant species (graphs a-d) included in the study?

Bromus erectus is unaffected by AMF diversity.

While examining a rock surface, you have discovered an interesting new organism. Which of the following criteria will allow you to classify the organism as belonging to Bacteria but not Archaea or Eukarya?

Cell walls are made primarily of peptidoglycan

Brown et al. and Morwood et al. reported in 2004 that they had found skeletal remains of a previously unknown type of hominin, now dubbed Homo floresiensis, on the Indonesian island of Flores. These hominins were small (approximately 1 meter tall) with small braincases (approximately 380 cubic centimeters) as compared with other hominins. The remains of H. floresiensis were found alongside handmade stone tools and the remains of dwarf elephants that also inhabited the island, suggesting that H. floresiensis was able both to make tools and to coordinate the hunting of animals much larger than itself. H. floresiensis is estimated to have lived at the site where the remains were found from at least 38,000 years ago to 18,000 years ago.Refer to the paragraph on Brown et al. and Morwood et al. Which would be the most feasible method of figuring out to which other hominin species H. floresiensis was most closely related?

Compare the skeletal morphology of H. floresiensis to that of each of the other hominin species.

If you wanted to use fungi to improve the environment, which of the following research goals would make the most sense?

Discover the lignin-digesting enzymes of fungi, and use them to digest plant tissues left over from food-crop residues and produce a biofuel.

Use the following information to answer the question.Suzanne Simard and colleagues knew that the same mycorrhizal fungal species could colonize multiple types of trees. They wondered if the same fungal individual would colonize different trees, forming an underground network that potentially could transport carbon and nutrients from one tree to another (S. Simard et al. 1997. Net transfer of carbon between mycorrhizal tree species in the field. Nature 388:579-82).Pots containing seedlings of three different tree species were set up and grown under natural conditions for three years (Fig. A). Two of the three species (Douglas fir, birch) could form ectomycorrhizal connections with the same fungal species, but the third species (cedar) could not form an ectomycorrhizal connection with the fungal species. In some of the pots, the researchers placed airtight bags over the Douglas fir and birch seedlings and injected carbon dioxide made from carbon-13 into the bags with the Douglas fir and carbon dioxide made from carbon-14 into the bags with the birch. (13C and 14C are different isotopes of carbon that can be detected and measured by researchers.) As the seedlings photosynthesized, the carbon dioxide was converted into sugars that could be tracked and measured by the researchers. The researchers measured whether the sugars in each plant contained only the carbon isotope that was in the air of their plastic bag or also the carbon isotope from the air around the other plant. 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.

Which of the following statements correctly describes a portion of the pine life cycle?

Female gametophytes use mitosis to produce eggs.

Use the following description to answer the question(s) below.The cycads, a mostly tropical phylum of gymnosperms, evolved about 300 million years ago and were dominant forms during the Age of the Dinosaurs. Though their sperm are flagellated, their ovules are pollinated by beetles. These beetles get nutrition (they eat pollen) and shelter from the microsporophylls. Upon visiting megasporophylls, the beetles transfer pollen to the exposed ovules. In cycads, pollen cones and seed cones are borne on different plants. Cycads synthesize neurotoxins, especially in the seeds, that are effective against most animals, including humans. On the Pacific island of Guam, large herbivorous bats called "flying foxes" commonly feed on cycad seeds, a potent source of neurotoxins. The flying foxes do not visit male cones. Consequently, what should be accurate?

Flying foxes can be dispersal agents of cycad seeds if the seeds sometimes get swallowed whole (in other words, without getting chewed).

With which of the following statements would a biologist be most inclined to agree

Humans and other apes represent divergent lines of evolution from a common ancestor

Big Bend National Park in Texas is mostly Chihuahuan desert, where rainfall averages about 10 inches per year. Yet, it is not uncommon when hiking in this bone-dry desert to encounter mosses and ferns. One such plant is called "flower of stone." It is not a flowering plant, nor does it produce seeds. Under arid conditions, its leaflike structures curl up. However, when it rains, it unfurls its leaves, which form a bright green rosette on the desert floor. Consequently, it is sometimes called the "resurrection plant." At first glance, it could be a fern, a true moss, or a spike moss.In which combination of locations would one who is searching for the gametophytes of flower of stone have the best chance of finding them?

In shady, moist places and underground, nourished there by symbiotic fungi

What is an accurate statement about the genus Sphagnum?

It represents a large repository of CO2 that is likely to be released with global warming.

You find a new species of worm and want to classify it. Which of the following lines of evidence would allow you to classify the worm as a nematode and not an annelid?

It sheds its external skeleton to grow.

A team of researchers has developed a poison that has proven effective against lamprey larvae in freshwater cultures. The poison is ingested and causes paralysis by detaching segmental muscles from the skeletal elements. The team wants to test the poison's effectiveness in streams feeding Lake Michigan, but one critic worries about potential effects on lancelets, which are similar to lampreys in many ways. Why is this concern misplaced?

Lancelets live only in saltwater environments.

Based on this tree, which statement is correct?

Salamanders are a sister group to the group containing lizards, goats, and humans.

Placing sponges as the basal metazoans on the basis of lack of tissues implies which of the following?

Sponge ancestors never had tissues

Use the following information and figures to answer the question.Many terrestrial arthropods exchange gases with their environments by using tracheae, tubes that lead from openings (called spiracles) in the animal's exoskeleton or cuticle directly to the animal's tissues. Some arthropods can control whether their spiracles are opened or closed; opening the spiracles allows the carbon dioxide produced in the tissues to travel down the tracheae and be released outside the animal. Klok et al. measured the carbon dioxide emitted over time (represented by VCO2) by several species of centipedes. The figures present graphs of their results for two species, Cormocephalus morsitans and Scutigerina weberi. (C. J. Klok, R. D. Mercer, and S. L. Chown. 2002. Discontinuous gas-exchange in centipedes and its convergent evolution in tracheated arthropods. Journal of Experimental Biology 205:1019-29.) Copyright 2002 The Company of Biologists and the Journal of Experimental Biology. Look at the graph for Scutigerina weberi (note the scale of the y-axis) in the figure. What is the best interpretation of these results?

The centipede had its spiracles open the entire time

What conclusion can best be drawn from the data in the table?

The expansion in number of Hox genes throughout vertebrate evolution cannot be explained merely by three duplications of the ancestral vertebrate Hox cluster.

Imagine that you are a graduate student seeking an idea for a research project that will help us understand the evolution of a parasitic lifestyle from a free-living lifestyle. Which of the following outcomes would you expect if you compare the genes of parasitic species to relatives that are free living?

The parasitic species will have fewer functioning genes than the free-living species because loss of many genes will not be harmful.

If all prokaryotes on Earth suddenly vanished, which of the following would be the most likely and most direct result?

The recycling of nutrients would be greatly reduced, at least initially.

Which of the following statements about human evolution is correct?

The upright posture and enlarged brain of humans evolved separately

Which of the following is characteristic of ciliates?

They are often multinucleate.

Which of the following statements is accurate with regard to the observation that "income levels in countries hard hit by malaria are 33% lower than in similar countries free of the disease."

This observation is an example of a correlation and therefore causality cannot be inferred as confidently as if we have results from a manipulated experiment.

Heterobasidion is a basidiomycete that contributes to mortality of trees. Kuhlman isolated 23 strains of Heterobasidion and applied them to 16 seedlings of 10 different tree species. Partial results of this experiment are shown in the table. (From Kuhlman, E. G. 1970. Seedling inoculations with Fomes annosus show variation in virulence and in host susceptibility.Which of the following conclusions can best be drawn from these results?

Tree species vary in their susceptibility to Heterobasidion.

You are given four test tubes, each containing an unknown protist, and your task is to read the following description and match these four protists to the correct test tube. 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 2 contains ________.

Triceratium (diatom)

The mechanism of cell crawling in protist species is not well defined. Pseudopodia extension involves interactions between actin and myosin (the same molecules that are involved in vertebrate muscle contraction). However, prior to the study described below, no one had provided convincing data that actin and myosin were actually involved in cell crawling in protists. Anatomical studies had identified the cytoskeletal protein actin just below the surface of the cell membrane in several species of protist, but physiological studies had failed to show a functional link between actin, myosin, and cell crawling.In a study by N. Poulsen et al. (Diatom gliding is the result of an actin-myosin motility system, Cell Motility and the Cytoskeleton 44 (1999):23-22), researchers tested whether motility in a particular species of diatom involves interactions between actin and myosin.

When the toxin was washed off the culture, the cells began to move again

You are hiking in a forest and come upon a mysterious plant, which you determine is either a lycophyte sporophyte, or a monilophyte sporophyte. Which of the following would be most helpful in determining the correct classification of the plant?

Whether it has microphylls or megaphylls.

Which characteristic is shared by cnidarians and flatworm?

a digestive system with a single opening

If you were asked to design a bryophyte that could be successful in a bare, moist area, which of the following possible adaptations would you include?

a symbiosis with nitrogen-fixing cyanobacteria

For several decades now, amphibian species worldwide have been in decline. A significant proportion of the decline seems to be due to the spread of the chytrid fungus, Batrachochytrium dendrobatidis (Bd). Chytrid sporangia reside within the epidermal cells of infected animals, animals that consequently show areas of sloughed skin. They can also be lethargic, which is expressed through failure to hide and failure to flee. The infection cycle typically takes four to five days, at the end of which zoospores are released from sporangia into the environment. In some amphibian species, mortality rates approach 100%; other species seem able to survive the infection.A researcher took water in which a Jl population had been thriving, filtered the water to remove all bacterial cells, and then applied the water to the skins of adult amphibians to see if there would subsequently be a reduced infection rate by Bd when frog skins were inoculated with Bd. For which of the following hypotheses is the procedure described a potential test?

a toxin secreted by Jl cells kills Bd cells when both are present together on frog skin

Which of the following characteristics is shared by a hagfish and a lamprey?

a well-developed notochord

Which of the following characteristics of plants is absent in their closest relatives, the charophyte algae?

alternation of multicellular generations

A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan. This bacterium derives nutrition by digesting human intestinal contents. Thus, this bacterium is an _____.

anaerobic chemoheterotroph

Which of the following phylogenetic trees appropriately groups organisms A to F? The asterisk shows the occurrence of a specific, rare mutation. The organisms that contain the rare mutation are also shown in bold.

asterisk on line leading to only ABC in bold

Which of the following pairs are the best examples of homologous structures?

bones in the bat wing and bones in the human forelimb

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

carex flacca (graph a)

Nudibranchs, a type of predatory sea slug, can have various protuberances (i.e., extensions) on their dorsal surfaces. Rhinophores are paired structures, located close to the head, which bear many chemoreceptors. Dorsal plummules, usually located posteriorly, perform respiratory gas exchange. Cerata usually cover much of the dorsal surface and contain nematocysts at their tips. The stingers of honeybees have a function most similar to that of_____.

cerata

Which of the following would you classify as something other than an animal?

choanoflagellate

A researcher is trying to construct a molecular-based phylogeny of the entire animal kingdom. Assuming that none of the following genes is absolutely conserved, which of the following would be the best choice on which to base the phylogeny?

collagen genes

A P. bursaria cell that has lost its zoochlorellae is aposymbiotic. If aposymbiotic cells have population growth rates the same as those of healthy, zoochlorella-containing P. bursaria in well-lit environments with plenty of prey items, then such an observation would be consistent with which type of relationship?

commensalistic

Use the following information to answer the question(s) below. 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. A P. bursaria cell that has lost its zoochlorellae is aposymbiotic. If aposymbiotic cells have population growth rates the same as those of healthy, zoochlorella-containing P. bursaria in well-lit environments with plenty of prey items, then such an observation would be consistent with which type of relationship?

commensalistic

Broad-spectrum antibiotics inhibit the growth of most intestinal bacteria. Consequently, a hospital patient who is receiving broad-spectrum antibiotics is most likely to become _____.

deficient in certain vitamins and nutrients

The phylogenetic tree shown_____.

depicts an evolutionary hypothesis

There is some evidence that reptiles called cynodonts may have had whisker-like hairs around their mouths. If true, then hair is a shared____.

derived character of mammals, but only if cynodonts are reclassified as mammals.

One small animal phylum (Placozoa) contains only two species, Trichoplax adhaerens (T. adhaerens) and T. reptans. T. adhaerens is the only species seen in over a century. Individuals are about 1 mm wide and only 27 μm high, are irregularly shaped, and consist of a total of about 2,000 cells, which are diploid (2n = 12). There are four types of cells, none of which are nerve or muscle cells, and none of which have cell walls. Individual animals move using cilia, and any "edge" can lead. T. adhaerens feeds on marine microbes, mostly unicellular green algae, by crawling atop the algae and trapping it between its ventral surface and the substrate. Enzymes are then secreted onto the algae, and the resulting nutrients are absorbed. T. adhaerens sperm cells have never been observed. Embryos up to, but not past, the 64-cell (blastula) stage have been observed.On the basis of information in the paragraph, which of these should be able to be observed in T. adhaerens?

eggs

Use the following description to answer the question(s) below.Oviparous (egg-laying) animals have internal fertilization (sperm cells encounter eggs within the female's body). Yolk and/or albumen is (are) provided to the embryo, and a shell is then deposited around the embryo and its food source. Eggs are subsequently deposited in an environment that promotes their further development, or are incubated by one or both parents. The yolk of an animal egg has what type of analog in angiosperms?

endosperm

A trend first observed in the evolution of the earliest tetrapods was_____.

feet with digits

Which of the following sex and generation combinations directly produces the megasporangium of pine ovules?

female sporophyte

A botanist discovers a new species of plant in a tropical rain forest. After observing its anatomy and life cycle, he notes the following characteristics: flagellated sperm, xylem with tracheids, separate gametophyte and sporophyte generations with the sporophyte dominant, and no seeds. This plant is probably most closely related to

ferns

Reinforced, threadlike pseudopods that can perform phagocytosis are generally characteristic of _____.

foramifera

Arrange the following in the correct sequence, from earliest to most recent, in which these plant traits originated.

gametophyte dominance, sporophyte dependence, sporophyte dominance, gametophyte independence, sporophyte dominance, gametophyte dependence.

The most direct ancestors of land plants were probably_____.

green algae

Nematodes and arthropods both _____.

grow in conjunction with shedding of their exoskeleton

Evidence of which structure or characteristic would be most surprising to find among fossils of the Ediacaran fauna?

hard parts

The reason that paralogous genes can diverge from each other within the same gene pool, whereas orthologous genes diverge only after gene pools are isolated from each other, is that_____.

having an extra copy of a gene permits modifications to the copy without loss of the original gene product

Arthropod exoskeletons and mollusk shells both _____.

help retain moisture in terrestrial habitats

Mitochondria are thought to be the descendants of certain alpha proteobacteria. They are, however, no longer able to lead independent lives because most genes originally present on their chromosome have moved to the nuclear genome. Which phenomenon accounts for the movement of these genes?

horizontal gene transfer

Which of the following changes would lead to an increase in surface-area-to-volume ratios?

increasing the number of layers in the chloroplasts of plants

Regarding these sequence homology data, the principle of maximum parsimony would be applicable in _____.

inferring evolutionary relatedness from the number of sequence differences.

Fishes that have swim bladders can regulate their density and, thus, their buoyancy. There are two types of swim bladder: physostomous and physoclistous. The ancestral version is the physostomous version, in which the swim bladder is connected to the esophagus via a short tube (see the figure above). The fish fills this version by swimming to the surface, taking gulps of air, and directing them into the swim bladder. Air is removed from this version by "belching." The physoclistous version is more derived, and has lost its connection to the esophagus. Instead, gas enters and leaves the swim bladder via special circulatory mechanisms within the wall of the swim bladder. If a ray-finned fish is to both hover (remain stationary) in the water column and ventilate its gills effectively, then what other structure besides its swim bladder will it use?

its opercula

If haustoria from the fungal partner were to appear within the photosynthetic partner of a lichen, and if the growth rate of the photosynthetic partner consequently slowed substantially, then this would support the claim that

lichens are not purely mutualistic relationships.

A biology student hiking in a forest happens on an erect, 15 cm tall plant that bears microphylls and a strobilus at its tallest point. When disturbed, the cone emits a dense cloud of brownish dust. A pocket magnifying glass reveals the dust to be composed of tiny spheres with a high oil content. This student has probably found a(n)

lycophyte sporophyte

The generative cell of male angiosperm gametophytes is haploid. This cell divides to produce two haploid sperm cells. What type of cell division does the generative cell undergo to produce these sperm cells?

mitosis

While sampling marine plankton in a lab, a student encounters large numbers of fertilized eggs. The student rears some of the eggs in the laboratory for further study and finds that the blastopore becomes the mouth. The embryo develops into a trochophore larva and eventually has a true coelom. These eggs probably belonged to a(n) _____.

mollusc

The legless condition that is observed in several groups of extant reptiles is the result of_____.

several instances of the legless condition arising independently of each other.

Compared to eukaryotes, prokaryotes are_____.

simpler morphologically, but more evolutionary primitive

Which species is most likely to be found in sewage treatment plants and in the guts of cattle?

species B

The sea slug, Pteraeolidia ianthina, can harbor living dinoflagellates (photosynthetic protists) in its skin. These endosymbiotic dinoflagellates reproduce quickly enough to maintain their populations. Low populations do not affect the sea slugs very much, but high populations (> 5 x 105 cells/mg of sea slug protein) can promote sea slug survival. According to the graph, during which season(s) of the year is the relationship between the sea slug and its dinoflagellates closest to being commensal?

spring

The common ancestors of birds and mammals were very early (stem) reptiles, which almost certainly possessed three-chambered hearts (two atria, one ventricle). Birds and mammals, however, are alike in having four-chambered hearts (two atria, two ventricles). The four-chambered hearts of birds and mammals are best described as_____.

structural analogies

Which structure of the amniotic egg most closely surrounds the embryo?

the amnion

Which of the following was probably the least important factor in bringing about the Cambrian explosion?

the movement of animals onto land

Which of the following is a major trend in land plant evolution?

the trend toward a sporophyte-dominated life cycle