Question 1

Which type of organism is most typical of herbivores?

Accepted Answer

Herbivores typically consume parts of plants without destroying them entirely, allowing the plant to continue growing and providing a sustainable food source.

Question 2

In Paine's classic study of sea star predation on mussel populations, he showed that in the absence of sea stars, experimental plots lost approximately half of the sessile invertebrate species usually present.This result suggests that

Accepted Answer

Paine's study demonstrates that the presence of predators (sea stars) can control prey density and thus maintain community species diversity. The loss of half of the sessile invertebrate species in the absence of sea stars suggests that the sea stars play an important role in regulating the populations of their prey and preventing monopolization of space and resources by certain species. This is an example of the trophic cascade effect, where the removal of a top predator can lead to significant changes in the abundance and diversity of lower trophic levels. Option A is not supported by the information provided in the question since the study focused on the effects of sea stars, not mussels, on community diversity. Option B is incorrect because the loss of half of the species in the absence of predators suggests that high prey density is not necessary to maintain diversity. Options D and E are also incorrect since there is no evidence to suggest that certain sessile invertebrate species can survive only in the presence of mussels or sea stars.

Question 3

Which of these interactions does not represent a typical parasite-host interaction?

Accepted Answer

This interaction represents a parasitoid-host interaction, which is different from a typical parasite-host interaction. In a parasitoid-host interaction, the parasite eventually kills the host, whereas in a typical parasite-host interaction, the parasite may harm the host but does not necessarily kill it. The other interactions represent typical parasite-host interactions.

Question 4

A small population of Canada lynx feeds on Arctic hares.Then snowshoe hares (the lynx's favorite prey) are introduced.The snowshoe hares reproduce rapidly, and their population explodes.Based on your knowledge of predator-prey interactions, what changes would you expect in the lynx population and in the population of Arctic hares, the lynx's previous prey?

Accepted Answer

With the increased availability of their favorite prey (snowshoe hares), the lynx population is likely to increase. However, this increased predation pressure on snowshoe hares will lead to a decrease in their population. As a result, the Arctic hare population may see a slight increase due to the reduced predation pressure from the lynx, but it is still likely to be negatively impacted by the introduction of the snowshoe hare. Therefore, the lynx population would increase and the Arctic hare population would decrease.

Question 5

An herbivore species would most likely exert strong selective pressure on its host plant species if the herbivore eats

Accepted Answer

A herbivore species that eats a large part of the plant biomass, including the entire flower, would exert strong selective pressure on its host plant species because it would directly affect the reproductive success of the plant. The herbivore would be removing key organs essential for the production of seeds and the continuation of the plant species. This creates strong selection pressure for plants that can resist herbivory or compensate for loss of organs. In contrast, herbivores that eat a small percentage of the plant biomass or only eat leaves may not have as much impact on the reproductive success of the plant, causing weaker selective pressure.

Question 6

Most plants defend themselves against herbivory by means of

Accepted Answer

The most common and effective way for plants to defend themselves against herbivory is through chemical defenses, such as producing toxins or unpleasant tastes that deter animals from eating them. While warning coloration and crypsis can also benefit some plants, thorns and spines and thick coverings are only effective against certain types of herbivores and are not widespread defense mechanisms in the plant kingdom.

Question 7

Microscopic study of the contact lens fluid of a person with an eye infection revealed a series of four nested parasites: an amoeba, which contained a giant virus, which contained a smaller virus, which contained chunks of parasitic DNA.How could these four parasites best be characterized?

Accepted Answer

The amoeba is a known pathogenic microparasite, while the viruses and parasitic DNA are symbiotic microparasites, but their pathogenicity is not specified.

Question 8

Many scientists think the great number of parasite species on Earth can be explained by the specialization parasites have undergone and continue to undergo.Which factor is likely most responsible for the continued evolution of new forms of parasites?

Accepted Answer

Constantly changing host environments provide selective pressures that can drive the evolution of new forms of parasites. As hosts evolve defenses against parasites, the parasites must also evolve to evade or overcome these defenses. Additionally, changes in host behavior or ecology can create new opportunities for parasites to exploit, leading to the evolution of new specialized parasite species.

Question 9

In nature, predator-prey cycles can continue for many years.In laboratory cultures, both populations quickly die off unless new individuals are periodically introduced (i.e., immigration occurs).Based on this information, cycles in nature might be maintained by any of these factors (or some combination of them) except

Accepted Answer

The inherent stability exerting control from within the predator-prey interaction does not explain the maintenance of cycles in nature, as the statement suggests that without immigration, both populations die off, indicating that external factors, rather than inherent stability, are crucial for maintaining these cycles.

Question 10

In pregnant women, the Zika virus causes serious birth defects.It is spread by the bite of the Aedes aegypti mosquito, which contracts it from an infected human.It must replicate and spread within the mosquito before it can infect a human.Infected humans can spread the virus through sex and from mother to unborn child.In this relationship, how can the Zika virus be characterized?

Accepted Answer

The Zika virus is a microparasite, meaning it is a small parasite such as a virus or bacteria, and an endoparasite, meaning it lives inside the host's body. It is not a macroparasite as it is not visible to the naked eye and does not live on the surface of the host's body. It is also not characterized as an ectoparasite as it is not a parasite that lives on the external surface of its host. Finally, it is a pathogen as it causes disease in its host.

Question 11

The graph below shows cycles of predators (lynx) and prey (snowshoe hares) over nearly a century.During this time, people were trapping both lynx and hares, thus limiting their populations.  If trapping of both species declined, what changes would be expected to occur in the hare and lynx populations?

Accepted Answer

The answer of The graph below shows cycles of predators...

Question 12

The H1N1 influenza virus responsible for the 2009 pandemic is an example of

Accepted Answer

The H1N1 influenza virus is a microparasite, which is a small pathogen that reproduces inside a host and causes disease.

Question 13

The biochemical diversity of plants is primarily due to

Accepted Answer

The biochemical diversity of plants is primarily due to coevolution with herbivores. Plant secondary metabolites, which are responsible for the biochemical diversity of plants, have evolved over time as a defense mechanism against herbivores.

Question 14

A bird is infested with the bloodsucking larvae of blowflies.The blowfly larvae fall off the bird and are themselves infested with parasitic wasps.The wasps contain a parasitic bacterium, which in turn is infested with bacteriophages, or parasitic viruses.This multitiered system could be considered evidence for

Accepted Answer

This multitiered parasitic relationship illustrates specialization among parasites, leading to a diversity of species each adapted to a specific host or niche within the ecosystem.

Question 15

The best characterization of pathogenic organisms is that all

Accepted Answer

Pathogenic organisms are best characterized by their ability to cause disease, not necessarily death, and they can belong to various categories including bacteria, viruses, fungi, and parasites (both micro and macro).

Question 16

A parasite lives in a chimpanzee's fur and is easily located and picked off by the troop's other chimpanzees during grooming.This parasite is both an

Accepted Answer

The parasite lives in the chimpanzee's fur, making it an ectoparasite because it lives on the outside of the host's body. It is also described as easily seen and picked off, implying it is large enough to be visible to the naked eye, which classifies it as a macroparasite.

Question 17

Butterfly caterpillars and adults are herbivores, and they exhibit many adaptations to this lifestyle.Which characteristic of butterflies is least likely to be an adaptation to herbivory?

Accepted Answer

Molting is a general growth process in insects, not specifically an adaptation to herbivory. It allows caterpillars to grow larger by shedding their exoskeleton, but it is not directly related to their diet of plants.

Question 18

Which feature of head lice is least likely to be an adaptation for their lifestyle as ectoparasites on humans?

Accepted Answer

The size difference between males and females is a common trait among parasitic organisms, but it is not necessarily an adaptation specific to head lice as an ectoparasite on humans.

Question 19

Which type of organisms would be most likely to evolve adaptations that would enable them to grasp onto and maintain a tight grip on their hosts?

Accepted Answer

Ectoparasitic organisms live on the surface of their host and often need to maintain a tight grip to avoid being dislodged, making adaptations for grasping particularly advantageous for them.

Question 20

Which type of animal has most likely evolved specialized detoxification systems?

Accepted Answer

The answer of Which type of animal has most likely...

Quiz 55: Species Interactions