Question 1

What might be the predominant lifestyle on Earth?

Accepted Answer

The answer of What might be the predominant lifestyle on...

Question 2

Polyphagous parasites feed on

Accepted Answer

Polyphagous parasites are capable of feeding on many different hosts, not limited to a single species or type of host.

Question 3

Which of the following lack chlorophyll and are totally dependent on the host plant for water and nutrients?

Accepted Answer

Holoparasites lack chlorophyll and are entirely dependent on their host plants for water and nutrients, unlike hemiparasites which can photosynthesize to some extent.

Question 4

The reduction in the density of chestnut trees in North America was due to

Accepted Answer

Chestnut blight, caused by a fungal pathogen (Cryphonectria parasitica), is responsible for the significant reduction in the density of chestnut trees in North America.

Question 5

Many species of ants "farm" aphids, protecting these insects and collecting concentrated sugars known as honeydew from them. The relationship between such an ant and its aphids is known as

Accepted Answer

In this relationship, both ants and aphids benefit, making it a form of mutualism. Specifically, it's called defensive mutualism because the ants protect the aphids from predators and parasites in exchange for food (honeydew), thus both parties gain a defensive advantage alongside their mutual benefits.

Question 6

A mutualism in each species can live without the other is termed a

Accepted Answer

Facultative mutualism refers to a relationship where both species benefit from the interaction but are not dependent on it for survival, meaning each species can live without the other.

Question 7

What is often true of the fruits eaten by birds and mammals?

Accepted Answer

Fruits eaten by birds and mammals often have attractive colors to signal ripeness and encourage consumption, which aids in seed dispersal.

Question 8

The seeds of many plant species are dispersed by a harmless temporary attachment to an animal's fur or feathers. This form of dispersal is known as

Accepted Answer

Phoresy refers to a form of commensalism where one organism (the phoront) uses another (the host), typically for transport, without causing it harm. In the context of seed dispersal, seeds attaching to an animal's fur or feathers for transport to new locations fits the definition of phoresy, as the seeds benefit from the dispersal while the animal is neither harmed nor benefited.

Question 9

Some scientists have suggested that recent outbreaks of sudden oak disease could be fought through the creation of transgenic plants with genetic resistance to sudden oak disease. What would be the source of this genetic resistance?

Accepted Answer

The source of genetic resistance for creating transgenic plants to combat sudden oak disease would likely come from the original host species in the source region of the disease. These species may have evolved resistance mechanisms over time, making them a valuable resource for developing resistant plants through genetic engineering.

Question 10

Top-down factors that can control the population sizes of plants or animals include

Accepted Answer

Top-down factors that control the population sizes of plants or animals typically involve predators, parasites, or diseases that reduce the population size by increasing mortality or reducing reproductive success. Seed-dispersing birds, widespread phoresy, resource partitioning, and Batesian mimicry are not considered top-down control mechanisms.

Question 11

Which of the following exert bottom-up control?

Accepted Answer

The answer of Which of the following exert bottom-up control?
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Question 12

The nitrogen-limitation hypothesis states that organisms select food in terms of the nitrogen content of the tissue. Why might this be true?

Accepted Answer

Animal tissue generally contains higher levels of nitrogen compared to plant tissue, which is a critical component for building proteins and nucleic acids. This makes animal tissue a more nitrogen-rich food source for organisms, supporting the nitrogen-limitation hypothesis.

Question 13

Parasitic relationships tend to be highly intimate.

Accepted Answer

Parasitic relationships are highly intimate because the parasite lives on or inside its host for an extended period, often evolving specific adaptations to closely interact with and exploit the host.

Question 14

Resource partitioning occurs between allopatric species.

Accepted Answer

Resource partitioning typically occurs between sympatric species that live in the same geographic area and thus need to minimize competition by utilizing different resources or niches.

Question 15

Species may NOT coexist if they occupy identical realized niches.

Accepted Answer

Species cannot coexist in the same location over the long term if they occupy identical realized niches due to competitive exclusion, which states that two species competing for the exact same resources cannot stably coexist.

Question 16

Fleas are endoparasites.

Accepted Answer

Fleas are ectoparasites, meaning they live on the outside of their host, not inside.

Question 17

Phoretic species are commensals.

Accepted Answer

Phoretic species are considered commensals because they engage in a relationship where one organism (the phoretic) is transported by another without causing harm, fitting the definition of commensalism.

Question 18

Humans exert top-down pressures on white-tail deer.

Accepted Answer

Humans exert top-down pressures on white-tail deer through hunting, habitat modification, and management practices, influencing their population dynamics and ecosystem roles.

Question 19

Using insects from the original homeland to control invasive weeds is a form of biological control.

Accepted Answer

This method, known as classical biological control, involves introducing natural enemies (such as insects) from the invasive species' original habitat to control their population in a new environment, thereby reducing the impact of the invasive weeds.

Question 20

Resource partitioning enables similar species to coexist in a community.

Accepted Answer

Resource partitioning involves different species adapting to utilize different resources or the same resource in different ways, reducing direct competition and allowing them to coexist within the same community.

Quiz 57: Species Interactions