Question 1

A plant species in a community grows very rapidly and uses excess amounts of surrounding soil resources.This results in a competitor species being eliminated from the community.The rapidly growing species (interactor) has a (positive/negative) _______ interaction with the eliminated (target) species.

Accepted Answer

The answer of A plant species in a community grows...

Question 2

There are several meanings of the word "community" and several ways to subdivide a community.Three are shown in the figure.Distinguish among these three subdivisions and explain why the members of a subdivision can be considered a community.

Accepted Answer

The answer of There are several meanings of the word...

Question 3

The type of succession most often resulting from human activities such as deforestation is _______ succession.

Accepted Answer

The answer of The type of succession most often resulting...

Question 4

Areas formed by volcanic activity, such as the Hawaiian Islands, have a lava substrate that is nitrogen-deficient.Many successful invaders in these areas are nitrogen fixers.By increasing nitrogen availability, these invaders enable the establishment of other invasive but non-nitrogen-fixing plant species.The changes to community structure result from _______.

Accepted Answer

The answer of Areas formed by volcanic activity, such as...

Question 5

One reason agricultural communities are often unstable is the practice of planting only a single species, which is called _______.

Accepted Answer

The answer of One reason agricultural communities are often unstable...

Question 6

A farmer has routinely planted soybeans, a nitrogen-fixing crop, in her fields, alternating it with corn, which requires high amounts of nitrogen.Then, for several years, she stops planting soybeans and plants only corn.Her corn crops decline more every year.This indicates that the interactor species (soybeans) has a (positive/negative) _______ interaction with the target species (corn).

Accepted Answer

The answer of A farmer has routinely planted soybeans, a...

Question 7

A gardener plants a bed that contains several blueberry bushes, several red clover and yarrow plants, and 100 strawberry plants.The strawberries provide a ground cover that conserves moisture and suppresses weeds.The red clover provides nitrogen, and the yarrow provides other nutrients for the blueberries.Because of its multiple species and their interactions, this bed can be considered a _______.

Accepted Answer

The answer of A gardener plants a bed that contains...

Question 8

Despite being so low in abundance that it is classified as a "near threatened" species, the jaguar plays an important role in structuring forest communities.It is thus considered a(n) _______ species.

Accepted Answer

The answer of Despite being so low in abundance that...

Question 9

A tropical rainforest is home to hundreds of species of trees that overlap in their resource requirements.Assuming multiple tree species have similar rates of population growth and similar access to the space and resources available, rainforest trees can be said to work in accordance with a neutral, or _______, model in maintaining species diversity.

Accepted Answer

The answer of A tropical rainforest is home to hundreds...

Question 10

Tropical forest fig trees provide habitat for thousands of species of animals and are an important food source for many more.Animals that live in and feed on figs provide prey for the diversity of rainforest predators.These functions of fig trees suggest they can be considered a(n) _______ species.

Accepted Answer

The answer of Tropical forest fig trees provide habitat for...

Question 11

A scientist removes one species from a community and observes how the abundance of a second "target" species is affected.The scientist is measuring the _______ between the two species.

Accepted Answer

The answer of A scientist removes one species from a...

Question 12

As trees grow in a forest, they shade the understory plants, decreasing their ability to receive light and carry out photosynthesis.This is an example of _______.

Accepted Answer

The answer of As trees grow in a forest, they...

Question 13

A parasitic wasp preys on caterpillars, which in turn feed on leaves of cabbage and other garden plants.Because the parasitic wasps keep the caterpillar population low, the leaves of the garden plants are not damaged.This is an example of a(n) _______ interaction.

Accepted Answer

The answer of A parasitic wasp preys on caterpillars, which...

Question 14

Refer to the figure, showing three aspects of biodiversity.Define each of these three aspects.Explain how they interact and how each is important for understanding community structure.

Accepted Answer

The answer of Refer to the figure, showing three aspects...

Question 15

The Mount St.Helens volcano erupted in 1980, and scientists have been studying the changes on the mountain ever since.Why are they so interested in studying this site? Name at least two concepts we now know more about as a result of their studies.

Accepted Answer

The answer of The Mount St.Helens volcano erupted in 1980,...

Question 16

A freak cold spell in October 2009 in the northeastern United States dramatically reduced the survival of several small mammal species.In this situation, the cold spell was acting as a(n) _______.

Accepted Answer

The answer of A freak cold spell in October 2009...

Question 17

The hypothesis formulated by Joseph Connell, in which he described the likely effect on species diversity of different levels of disturbance in a community, is known as the _______ hypothesis.

Accepted Answer

The answer of The hypothesis formulated by Joseph Connell, in...

Question 18

Explain the concept of "filters" in determining which species become members of a community.Describe the three major filters determining community structure.

Accepted Answer

The answer of Explain the concept of "filters" in determining...

Question 19

As a community's species richness increases, its community function generally _______.

Accepted Answer

The answer of As a community's species richness increases, its...

Question 20

Bison were introduced to a small fenced-in prairie region and allowed to reproduce.The bison soon overpopulated the area and overgrazed the native prairie grasses.After several years of overpopulation and overgrazing, managers removed the bison.However, after 10 years, the prairie has still not returned to its original species composition.This suggests it has undergone the process of _______.

Accepted Answer

The answer of Bison were introduced to a small fenced-in...

Quiz 56: Communities