Question 1

Which interaction is the clearest example of amensalism?

Accepted Answer

Amensalism is an interaction where one species is harmed while the other is unaffected. In choice C, an algal bloom causes fish deaths without any benefit to the algae, fitting the definition of amensalism.

Question 2

Refer to the table showing major types of interactions between species and the positive or negative influences of each interaction type.  What symbols should replace the "Y" and "Z," respectively, in the table?

Accepted Answer

B

Question 3

Two species of beetles are herbivores on the same host plant, and the presence of either species reduces the population growth of the other.The relationship between the beetles is therefore best described as

Accepted Answer

The relationship between the two species of beetles is that of competition. Both species are herbivores on the same host plant, and the presence of one species reduces the population growth of the other species. This indicates that they are competing for the same resources, and therefore, the relationship is competitive.

Question 4

Two species of lionfish have recently invaded the Caribbean, the Gulf of Mexico, and the Western Atlantic region.Comparing these predatory fishes with their native competitors, the activity of the lionfish could best be classified as

Accepted Answer

Lionfish are considered strong predators, as they have few natural predators and feed on a wide range of prey. Their effects on competitors are asymmetrical, as they have the potential to outcompete or prey on native species, leading to declines in their populations.

Question 5

Another way to describe coevolution is

Accepted Answer

Coevolution involves the reciprocal adaptation of two or more species to each other over a long period of time. Therefore, the best choice to describe coevolution is D) reciprocal adaptation.

Question 6

In an experiment involving two annual plants that grow in disturbed habitats, equal numbers of seedlings of the two species were grown together.Plant A grew much larger than plant B during the same time period.Would this interaction be considered asymmetrical? Why or why not?

Accepted Answer

Asymmetrical interaction refers to a situation where one species benefits or harms the other to a greater extent than vice versa. In this case, plant A grew much larger than plant B, indicating that it benefited more from the interaction than plant B did. Therefore, the interaction can be considered asymmetrical.

Question 7

Refer to the table showing major types of interactions between species and the positive or negative influences of each interaction type.  What type of interaction is represented by the "X" in the table?

Accepted Answer

The answer of Refer to the table showing major types...

Question 8

Which is an example of a mutualistic interaction?

Accepted Answer

A bacterium living in a plant's roots and fixing nitrogen provides a service to the plant by providing nutrients, and in return, the plant provides nutrients to the bacterium. This is an example of mutualism, where both organisms benefit from the interaction.

Question 9

A survey of predator-prey relationships shows that the fastest predators are usually found in regions where the fastest prey are found.The most likely explanation for this is

Accepted Answer

Reciprocal adaptations involve the co-evolution of predators and prey, leading to the development of adaptations that allow each to become faster or better at capturing or evading the other. As a result, regions with faster prey will likely select for faster predators, and vice versa.

Question 10

Which interaction is a positive interaction?

Accepted Answer

Mutualism is a positive interaction where both species benefit from the relationship.

Question 11

Which relationship has negative consequences for both species involved?

Accepted Answer

Competition between two species typically results in negative consequences for both parties involved, as they struggle over limited resources such as food, water, or territory, which can hinder growth, survival, or reproduction for both competitors.

Question 12

Which relationship is least likely to result in coevolution?

Accepted Answer

Amensalism is the least likely to result in coevolution because it involves a relationship where one species is harmed while the other is unaffected. This asymmetry means there is less direct pressure for both species to adapt in response to each other compared to the other relationships listed, which involve more direct interactions and mutual influences.

Question 13

The relationship between a zebra and the lion that eats it is an example of

Accepted Answer

The relationship between a zebra and the lion that eats it is one of predation, in which the lion benefits (by getting food) and the zebra is harmed (by being eaten).

Question 14

Although most herbivory harms the plant, some herbivorous interactions do not.Which is not a harmful interaction?

Accepted Answer

Eating blueberries and dispersing their seeds through excretion is a form of mutualism rather than harm, as it aids in the plant's reproduction.

Question 15

A cow's rumen, or first stomach, provides the ideal environment for a variety of microbes.When a cow consumes grass, these microbes digest the grass, releasing nutrients, which both they and the cow use.While most of the microbes remain in the rumen, some are killed during digestion and provide additional nutrition for the cow.This complex relationship between the cow and its microbes has features of which two categories of interactions?

Accepted Answer

The relationship between the cow and the microbes in its rumen involves both mutualism (the microbes digest the grass and release nutrients that benefit both the microbes and the cow) and predation (some microbes are killed during digestion and provide additional nutrition for the cow).

Question 16

Suppose the fecal matter from dogs helps fertilize a species of grass, thus increasing the grass's ability to grow in a particular area.The relationship between the dogs and the grass would be described as

Accepted Answer

In this scenario, the dogs benefit neither nor are harmed by their fecal matter helping the grass grow, while the grass benefits from the nutrients provided by the fecal matter. This describes a commensal relationship, where one organism benefits and the other is neither helped nor harmed.

Question 17

Although lichens look like single organisms, they are actually an association between a fungus and a photosynthetic partner, usually an alga.The lichen association is considered mutualistic, but the relationship also shows some features of parasitism.Which fact about lichens suggests parasitism rather than mutualism?

Accepted Answer

The fact that nutrients always flow from algae to fungi but do not always flow from fungi to algae suggests a parasitic element in the relationship, as it implies that the algae may not always benefit from the association.

Question 18

The South American tree sloth feeds on leaves and buds, which are digested by bacteria that inhabit the sloth's stomach.It is difficult for predators to see the sloth in a tree, because it is tinted green from the cyanobacteria that live in its fur.A variety of nonbiting insects also live in the fur but appear not to affect the sloth.This suggests that the sloth has mutualistic interactions with which two sets of organisms?

Accepted Answer

The statement suggests that the digestive bacteria and cyanobacteria have a mutualistic interaction with the sloth, as the cyanobacteria provide camouflage and the bacteria aid in digestion. There is no evidence to support mutualistic interactions with leaves and buds, insects, or both.

Question 19

Plants and mycorrhizae (fungi that grow in association with plant roots) are usually mutualistic.The fungus absorbs water and minerals, such as phosphorus, from the soil, which the plant uses.The plant provides the fungus with carbohydrates.In soils where phosphorus is low, nutrient transfer from fungus to plant may increase plant fitness.But in very fertile soils, the net benefit of the interaction may become negative, with the fungus acting more as a parasite than a mutualist.Which is the best description of the change in this interaction?

Accepted Answer

The description of the change suggests that the interaction moves along a continuum in response to changes in the environment. Initially, in low-phosphorus soils, the interaction is mutualistic, with the fungus providing necessary nutrients to the plant in exchange for carbohydrates. However, in very fertile soils, the net benefit of the interaction may become negative, with the fungus acting more as a parasite than a mutualist, suggesting a shift towards a more parasitic relationship. This change is not a fixed evolutionary change but rather a dynamic response to environmental conditions.

Question 20

While pursuing its prey, a bear destroys a shrub.The relationship between the bear and the shrub would be described as

Accepted Answer

Amensalism is a type of interaction where one organism is harmed while the other is unaffected. In this case, the shrub is destroyed (harmed) by the bear (which is unaffected) as it pursues its prey, fitting the definition of amensalism.

Quiz 55: Species Interactions