Organisms in Ecosystems Topic Test

How can an increase in biodiversity lead to an increase in ecosystem stability?

b. A more biodiverse ecosystem has a higher chance of adapting to species changes.

Which of the following is not an example of predation?

b. A tree obtaining nutrients from the soil

The Great Burdock plant's seeds have spines on them that attach to the fur of animals that brush against it. The seed then travels with the animal until it eventually falls off, which spreads the plant's seeds farther than the plant could have done. What type of symbiotic relationship is this?

b. Commensalism

Variation of ecological habitats within a species is characteristic of which type of diversity?

b. Ecosystem diversity

Which of the following is the best description of the cane toad's introduction to Australia?

b. It was a failed biological control mechanism for cane beetles.

Bees obtain food they need from flowers. The flowers benefit by having their pollen dispersed by the bees as they travel from flower to flower. What type of symbiotic relationship is this?

b. Mutualism

What is a possible cause for a decrease in ecosystem productivity?

b. a decrease of the biodiversity of an ecosystem

Living organisms interact in a variety of ways for a variety of purposes. The imperial shrimp rides on sea cucumbers as they travel underwater. This interaction enables the shrimp to use little to no energy to move between the areas in which it feeds. The sea cucumber is typically unaware that the shrimp is using it for transport. Which type of interaction occurs between the imperial shrimp and its host organism?

b. commensalism

Which of the following is a possible reason for migration?

b. diminished food supply

Organisms are dependent on each other for the energy they need to survive. Photos (left to right) by Mehmet Karatay, Jens Buurgaard Nielsen, Furryscaly, and Walter Siegmund. What would occur if the snake population is removed from the ecosystem pictured above?

b. the mouse population increases

The Hawaiian Islands are home to many endangered species. Why do you think the Hawaii Department of Agriculture is so strict about allowing nonnative species onto the islands?

c. It is so strict because a foreign species could compete with a native species and drive it to extinction.

The organism P. malariae lives in red blood cells, causing the host organism to experience high fevers and chills. What type of relationship is this?

c. Parasitism

What discovery led Darwin to develop his theories on adaptation?

c. The birds Darwin found in the Galapagos were different types of finches, not separate types of birds.

What are the three types of interactions between organisms in an ecosystem?

c. competition, predation, and symbiosis

Interactions between organisms and their environment impact the organism's overall population. The jaguar Panthera onca is the largest cat found in North America. It is found in areas across the Southwest, including Arizona, New Mexico, and Texas. It is a carnivore with powerful jaws and sharp teeth. Which concept is shown by the relationship between the jaguar and deer?

c. predator-prey

A variety of different mechanisms in nature help create diversity in organism populations. The tundra found in the northernmost parts of the planet is the world's youngest biome. The tundra is home to a variety of plants and animals. Organisms that can be found in the tundra include shrubs, mosses, caribou, polar bears, and wolves. Which mechanism do the different organism populations found across the tundra exemplify?

c. species diversity

When the comb jelly, Mnemiopsis leidyi, was introduced into the Black Sea, its population exploded to 500 comb jellies per cubic yard in 1988. The jellies devoured all the zooplankton and fish larvae, drastically reducing the numbers of the native fish populations. This situation demonstrates _______.

c. the impact of removing or adding organisms to an ecosystem.

Which of the following is an example of a biochemical adaptation?

c. being immune to scorpion stings

What is the purpose of mimicry?

d. All of the above

Why is it necessary to eliminate absolutely all invasive fire ant colonies to eradicate the invasive population?

d. Fire ants spread by winged members and by hitching rides so a single colony can cause infestation.

Which of the following is not true about Darwin's book On the Origin of Species?

d. It was based on his findings in South Africa.

Consider the following food chain: Garden plants are eaten by snails, which are eaten by birds, which are eaten by the household cat. What happens to the other members of the food chain if the cat is removed?

d. The number of plants and birds increase and the number of snails decreases.

The competitive exclusion principle states that _______.

d. when two organisms attempt to fill the same niche, one will exclude the other from the ecosystem

Compared to the time he spent in other parts of South America, Darwin spent little time collecting specimens in the Galapagos.

false

Migration is always temporary.

false

Organisms do not adapt as a result of competition for resources.

false

Organisms that have a physical trait that makes it easier for them to access food supplies are unlikely to pass on that trait to their offspring.

false

Territorial behavior does not extend to organisms of different species.

false

The terms commensalism and mutualism have the same meaning and are interchangeable.

false

An increase in the biodiversity of an ecosystem leads to an increase in its productivity.

true

Charles Darwin spent over 20 years developing his theory of natural selection.

true

Similarities between seemingly unrelated organisms can be explained by Darwin's theory that organisms come from common ancestors.

true

The competitive exclusion principle states that two organisms cannot fill the same niche.

true

The loss of an organism at the bottom of a food chain negatively impacts all organisms in the chain.

true

Which of the following are most responsible for the success of the cane toad as an invasive species in Australia?

a. venom glands and varied diet

Which of the following scenarios is representative of mutualism?

a. Barnacles living on whales

Deer run in zigzag patterns when being chased by predators. What type of adaptation is this?

a. Behavioral

Which of the following is not a part of Darwin's theory of evolution?

a. Changes in organisms occur immediately.

Which of the following is a possible long-term consequence of two organisms occupying the same niche?

a. Local extinction

Which of the following statements about migration is true?

a. Migration is always from one region to another.

How does a decrease in biodiversity impact an ecosystem?

A decrease in biodiversity causes a decrease in ecosystem stability, because a change to one organism will have a greater impact on the entire ecosystem. With greater biodiversity, the loss of one type of organism could be moderated by the adaptation of other organisms to fill its role. This is less likely in an ecosystem with less biodiversity.

When might an increase in biodiversity lead to a decrease in the stability of an ecosystem?

An increase in biodiversity usually leads to an increased stability, but in the case of an invasive species it would lead to a decreased stability.

Consider the following food chain: Garden plants are eaten by snails, which are eaten by birds, which are eaten by the household cat. What happens to the other members of the food chain if the garden is removed?

a. The number of snails and birds decrease.

Explain how the concept of the "survival of the fittest" relates to the theory of evolution.

Darwin's theory of evolution includes the concept that species change over time and that these changes occur gradually. Organisms that are not able to compete for resources effectively do not survive. The organisms that remain are able to pass on their more desirable traits to their offspring, which enables the species to evolve over time.

What is the purpose of hibernation?

Hibernation is an adaptation that allows animals to survive cold temperatures when food is scarce. Hibernating animals slow their metabolism so that they use less energy, which enables them to live off fat storage until the air is warmer.

Explain how microevolution and migration can affect an ecosystem.

Migration can negatively impact an ecosystem if the migration is permanent and leads to the loss of native species. Temporary migration, such as in the case of birds flying south in the winter, can maintain the biodiversity of an ecosystem. Microevolution, like migration, can aid the survival of native species.

Use the concept of natural selection to explain why organisms typically adapt over time.

Natural selection is the process by which organisms which are not as well adapted to their environment do not survive long enough to pass their less favorable traits on to the next generation of their species. Eventually, the more favorable traits are incorporated into a species as the organisms that had those traits survive while the ones who do not die. This process takes time because it occurs through individuals with the favorable traits passing those traits on to future generations. Typically, the less favorable traits will not be eradicated in one generation.

How does competition for resources lead to adaptations?

Organisms that are best suited for survival in their environment will be able to compete for limited resources better than organisms that are not well suited to their environment. The organisms that are able to get the resources they need are more likely to survive and pass their beneficial traits on to their offspring, which is what leads to species adaptation.

What are three reasons that organisms interact?

The three reasons that organisms interact mating, competition for food resources, defense, and assertion of dominance.

Which of the following scenarios is representative of commensalism?

c. Birds following grazing animals who stir up insects

Which of the following is the best explanation for why finches on one of the islands in the Galapagos have large beaks while finches on another island have small beaks?

c. Finches spontaneously changed their beak size in order to better access food supplies.