Test 3 Flashcards
What do fungi and arthropods have in common?
both groups use chitin for support
Fungi have an extremely high surface-area-to-volume ratio. What is the advantage of this to an organism that gets most of its nutrition through absorption?
the larger surface area allows for more material to be transported through the cell membrane
Based on the idea that fungi have pores between their cell walls, which allow cytoplasm to move from one end of the mycelium to the other, which of the following hypotheses is the most plausible?
If a single mycorrhizal fungus formed symbiotic associations with more than one tree, carbon could travel from one plant to another
If all fungi in an environment that perform decomposition were to suddenly die, then which group of organisms should benefit most, due to the fact that their fungal competitors have been removed?
prokaryotes
When a mycelium infiltrates an unexploited source of dead organic matter, what are most likely to appear within the food source soon thereafter?
fungal enzymes
The functional significance of porous septa in certain fungal hyphae is most similar to that represented by which pair of structures in animal cells and plant cells, respectively?
gap junctions—- plasmodesmata
A fungal spor germinates, giving rise to a mycelium that grows outward into the soil surrounding the site where the spore originally landed. Which of the following accounts for the fungal movement, as described here?
cytoplasmic streaming in hyphae
When pathogenic fungi are found growing on the roots of grape vines, grape farmers sometimes respond by covering the ground around their vines with plastic sheeting and pumping a gaseous fungicide into the soil. The most important concern of grape farmers who engage in this practice should be that the _____.
fungicide might also kill mycorrhizae
The adaptive advantage associated with the filamentous nature of fungal mycelia is primarily related to _____.
an extensive surface area well suited for invasive growth and absorptive nutrition
Some fungal species can kill herbivores while feeding off of sugars from its plant host. What type of relationship does this fungus have with its host?
mutualistic
At which stage of a basidiomycete’s life cycle would reproduction be halted if an enzyme that prevented the fusion of hyphae was introduced?
plasmogamy
Deuteromycetes_________.
are the group of fungi that have, at present, no known sexual stage
Plasmogamy can directly result in which of the following?
- cells with a single haploid nucleus
- heterokaryotic cells
- dikaryotic cells
- cells with two diploid nuclei
2 or 3
After cytokinesis occurs in budding yeasts, the daughter cell has a _____.
similar nucleus and less cytoplasm than the mother cell
In most fungi, karyogamy does not immediately follow plasmogamy, which consequently______.
results in heterokaryotic or dikaryotic cells
Asexual reproduction in yeasts occurs by budding. Due to unequal cytokinesis, the “bud” cell receives less cytoplasm than the parent cell. Which of the following should be true of the smaller cell until it reaches the size of the larger cell?
it should produce fewer fermentation products per unit time
The microsporidian Brachiola gambiae parasitizes the mosquito Anopheles gambiae. Adult female mosquitoes must take blood meals for their eggs to develop, and it is while they take blood that they transmit malarial parasites to humans. Male mosquitoes drink flower nectar. If humans are to safely and effectively use Brachiola gambiae as a biological control to reduce human deaths from malaria, then how many of the following statements should be true?
- Brachiola should kill the mosquitoes before the malarial parasite they carry reaches maturity.
- The microsporidian should not be harmful to other insects.
- Microsporidians should infect mosquito larvae, rather than mosquito adults.
- The subsequent decline in anopheline mosquitoes should not significantly disrupt human food resources or other food webs.
- Brachiola must be harmful to male mosquitoes, but not to female mosquitoes.
1,2, and 4
Why are mycorrhizal fungi superior to plants at acquiring mineral nutrition from the soil?
fungi secrete extracellular enzymes that can break down large molecules
Fossil fungi date back to the origin and early evolution of plants. What combination of environmental and morphological change is similar in the evolution of both fungi and plants?
colonization of land and loss of flagellated cells
The multicellular condition of animals and fungi seems to have arisen _____.
by convergent evolution
Which feature seen in chytrids supports the hypothesis that they diverged earliest in fungal evolution?
flagellated spores
It has been hypothesized that fungi and plants have a mutualistic relationship because plants make sugars available for the fungi’s use. What is the best evidence in support of this hypothesis?
radioactively labeled sugars produced by plants eventually show up in the fungi with which they are associated
you observe the gametes of a fungal species under the microscope and realize that they resemble animal sperm. To which of the following group does the fungus belong?
chytrids
Which of the following has the least affiliation with all the others? A) Glomeromycota B) mycorrhizae C) lichens D) arbuscules
c
Arrange the following in order from largest to smallest.
- ascospore
- ascocarp
- ascomycete
- ascus
3—2—4—1
Arrange the following in order from largest to smallest, assuming that they all come from the same fungus.
- basidiocarp
- basidium
- basidiospore
- mycelium
- gill
4—1—5—2—3
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?
the hypothesis that Jl cells infect and kill Bd cells when both are present together on frog skin
Basidiomycetes are the only fungal group capable of synthesizing lignin peroxidase. What advantage does this group of fungi have over other fungi because of this capability?
this fungal group can break down the tough lignin, which cannot be harnessed for energy, to get to the more useful cellulose
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 billionaire buys a sterile volcanic island that recently emerged from the sea. To speed the arrival of conditions necessary for plant growth, the billionaire might be advised to aerially sow what over the island?
soredia
Orchid seeds are tiny, with virtually no endosperm and with miniscule cotyledons. If such seeds are deposited in a dark, moist environment, then which of the following represents the most likely means by which fungi might assist in seed germination, given what the seeds lack?
by providing the embryos with some of the organic nutrients they have absorbed
Which of the following best describes the physical relationship of the partners involved in lichens?
photosynthetic cells are surrounded by fungal hyphae
Mycorrhizae are to the roots of vascular plants as endophytes are to vascular plants’ _____.
leaf mesophyll
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
Which of the following is (are) unique to animals?
A) the structural carbohydrate, chitin
B) nervous system signal conduction and muscular movement
C) heterotrophy
D) flagellated gametes
b
The larvae of some insects are merely small versions of the adult, whereas the larvae of other insects look completely different from adults, eat different foods, and may live in different habitats. Which of the following is most directly involved in the evolution of these variations in metamorphosis?
Changes in the homeobox genes governing early development
Both animals and fungi are heterotrophic. What distinguishes animal heterotrophy from fungal heterotrophy is that most animals derive their nutrition by _____.
ingesting it
What do animals ranging from corals to monkeys have in common?
presence of Hox genes
In individual insects of some species, whole chromosomes that carry larval genes are eliminated from the genomes of somatic cells at the time of metamorphosis. A consequence of this occurrence is that _____.
we could not clone a larva from the somatic cells of such an adult insect
Which of the following would you classify as something other than an animal? A) sponges B) coral C) jellyfish D) choanoflagellates
chanoflagellates
The evolution of animal species has been prolific (the estimates go into the millions and tens of millions). Much of this diversity is a result of the evolution of novel ways to _____.
sense, feed, and move
The last common ancestor of all animals was probably a _____.
flagellated protist
Evidence of which structure or characteristic would be most surprising to find among fossils of the Ediacaran fauna?
hard parts
Which statement is most consistent with the hypothesis that the Cambrian explosion was caused by the rise of predator-prey relationships? The fossil record reveals an increased incidence of _____.
hard parts
Which of the following genetic processes may be most helpful in accounting for the Cambrian explosion?
gene duplication
Whatever its ultimate cause(s), the Cambrian explosion is a prime example of _____.
adaptive radiation
Arthropods invaded land about 100 million years before vertebrates did so. This most clearly implies that _____.
arthropods have had more time to coevolve with land plants than have vertebrates
Which tissue type, or organ, is NOT correctly matched with its germ layer tissue?
nervous—- mesoderm
While looking at some seawater through your microscope, you spot the egg of an unknown animal. Which of the following tests could you use to determine whether the developing organism is a protostome or a deuterostome? See whether the embryo _____.
exhibits spiral cleavage or radial cleavage
In examining an unknown animal species during its embryonic development, how can you be sure what you are looking at is a protostome and not a deuterostome?
you see a mouth, but not an anus
Which of the following is a feature of the tube-within-a-tube body plan in most animal phyla?
the mouth and anus form the ends of the inner tube.
If you think of the earthworm body plan as a drinking straw within a pipe, where would you expect to find most of the tissues that developed from endoderm?
lining the straw
Among protostomes, which morphological trait has shown the most variation?
type of body cavity (coelom vs. pseudocoelom vs. no coelom)
What do all deuterostomes have in common?
the pore (blastopore) formed during gastrulation becomes the anus
Soon after the coelom begins to form, a researcher injects a dye into the coelom of a deuterostome embryo. Initially, the dye should be able to flow directly into the _____.
archenteron
You have before you a living organism, which you examine carefully. Which of the following should convince you that the organism is acoelomate?
muscular activity of its digestive system distorts the body wall
What was an early selective advantage of a coelom in animals? A coelom _____.
contributed to a hydrostatic skeleton, allowing greater range of motion
The protostome developmental sequence arose just once in evolutionary history, resulting in two main subgroups—Lophotrochozoa and Ecdysozoa. What does this finding suggest?
division of these two groups occurred after the protostome developmental sequence appeared
Which of these, if true, would support the claim that the ancestral cnidarians had bilateral symmetry?
- Cnidarian larvae possess anterior-posterior, left-right, and dorsal-ventral aspects.
- Cnidarians have fewer Hox genes than bilaterians.
- All extant cnidarians, including Nematostella, are diploblastic.
- β-catenin turns out to be essential for gastrulation in all animals in which it occurs.
- All cnidarians are acoelomate.
1 and 4
An organism that exhibits cephalization probably also______.
is bilaterally symmetrical
Suppose a researcher for a pest-control company developed a chemical that inhibited the development of an embryonic mosquito’s endodermal cells. Which of the following would be a likely mechanism by which this pesticide works?
the mosquito would have trouble digesting food, due to impaired gut function
Fossil evidence indicates that the following events occurred in what sequence, from earliest to most recent?
- Protostomes invade terrestrial environments.
- Cambrian explosion occurs.
- Deuterostomes invade terrestrial environments.
- Vertebrates become top predators in the seas.
2—3—1—4
What is the probable sequence in which the following clades of animals originated, from earliest to most recent?
- tetrapods
- vertebrates
- deuterostomes
- amniotes
- bilaterians
5—3—2—1—4
The most ancient branch point in animal phylogeny is the characteristic of having _____.
true tissues or no tissues
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
The common ancestor of the protostomes had a coelom. What does this suggest?
the body cavity evolved before the lophophore
The Hox genes came to regulate each of the following. From earliest to most recent, in what sequence did these events evolve?
- identity and position of paired appendages in protostome embryos
- anterior-posterior orientation of segments in protostome embryos
- positioning of tentacles in cnidarians
- anterior-posterior orientation in vertebrate embryos
3—2—1—4
The last common ancestor of all bilaterians is thought to have had four Hox genes. Most extant cnidarians have two Hox genes, except Nematostella (of β-catenin fame), which has three Hox genes. On the basis of these observations, some have proposed that the ancestral cnidarians were originally bilateral and, in stages, lost Hox genes from their genomes. If true, this would mean that _____.
the radial symmetry of extant cnidarians is secondarily derived, rather than being an ancestral trait
Some researchers claim that sponge genomes have homeotic genes, but no Hox genes. If true, this finding would _____.
confirm the identity of sponges as “basal animals”
The feeding stage of cycliophorans _____.
- is autotrophic
- is sessile
- captures food in a manner similar to that of animals with lophophores
- shows radial symmetry
1, 2 and 3