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Unit 2 Test on Stability

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A moth and a beetle both lay eggs on the same species of plant and the larvae of both develop on the plant. Removal experiments show that the moth and the beetle each perform less well on the plant when the other species is removed. The relationship between the moth and the beetle is best described as
parasitism.
mutualism.
commensalism.
herbivory.
The fecal matter from giraffes helps fertilize a particular species of plant, thus increasing the plant’s ability to grow in a particular area. The plant has no effect on giraffes. The relationship between the giraffes and the plants is best described as
commensalism.
parasitism.
mutualism.
herbivory.
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 both for their own and for the cow’s use. While most of the microbes continue to live in the rumen, some of them are killed during the digestive process and provide additional nutrition for the cow. This complex relationship between the cow and her microbes has features of which two categories of interactions?
Mutualism and predation
Competition and mutualism
Commensalism and mutualism
Predation and parasitism
Which of the following provides the most accurate example of primary succession?
Lichen and grass communities establishing themselves on a recently-formed island, resulting from an uplift in the ocean bedrock
Coral reef and aquatic wildlife communities that have re-established themselves in regions of the South Pacific that were evacuated following the nuclear tests conducted by the U.S. military
Seedlings establishing themselves in a heavily logged area where the seed-tree cutting method was employed
Native grass communities forming after a wildfire burned through a meadow/woodland ecosystem
Which of the following are least likely to be present during primary succession?
Lichen
Fungi
Moss
Trees
The diagram below represents different stages of an ecosystem over a period of time. Which stage of the ecosystem has the greatest long-term stability?

D
C
B
A
Refer to the diagram. During which stage would you find a climax community represented?

C
B
D
A
Over a long period of time, the stages represented in the diagram on the right were each present in a particular ecosystem.


After a forest fire, what is the most likely order in which these stages appeared?
A → B → C → D
B → D → C → A
B → C → D → A
D → C → A → B
The diagram below represents a process that occurs in nature.


This diagram can be used to illustrate the
evolution of mosses to trees over 200 years
effect of human intervention on a stable ecosystem
ecological succession from bare rock to stable ecosystem
effects of reduced competition between different types of plant life
The graph below shows the growth of two populations of paramecia grown in the same culture dish for 14 days. Which ecological concept is best represented by the graph?

decomposition
competition
equilibrium
recycling
Using the graph, what is the dependent variable?

Number of paramecium
Days
Time
Paramecium aurelia
Using the graph, which organism was better fit for the environment?

Paramecium caudatum
Neither
Both
Paramecium aurelia
In December 2004, a tsunami (giant wave) destroyed many of the marine organisms along the coast of the Indian Ocean. What can be expected to happen to the ecosystem that was most severely hit by the tsunami?
The organisms in the ecosystem will become extinct.
Ecological succession will no longer occur in this marine ecosystem.
The ecosystem will change until a new stable community is established.
Succession will continue in the ecosystem until one species of marine organism is established.
What will most likely occur if two different plant species compete for the same requirements in an ecosystem?
One species may be eliminated from that ecosystem.
They will alter the environment so that they can both survive in that ecosystem.
One species may adapt to a different environment.
They will usually develop different requirements.
The amount of energy the producers in this energy pyramid provide the primary consumers is 54,000 joules. From this amount, 540 joules are provided to the tertiary consumers.


Based on this model, how much of the energy was provided to secondary consumers?
540 J
53,460 J
54 J
5,400 J
During ecological succession, how does the growth of young hardwoods affect the organisms living in an ecosystem?
In autumn, falling leaves provide a source of energy for decomposers such as fungi.
The trees provide shelter and food for a variety of mammals, insects, and birds.
All of the above
Grasses and low shrubs are unable to obtain the amount of light they need to survive, so there are small numbers of them
Some relationships between different organisms are shown in the table.


Which table correctly identifies each type of interaction described?
Part of a hydrothermal vent food web is represented in the diagram.



Which organisms are both secondary and tertiary consumers in this food web?
Chemosynthetic bacteria and amphipods
Ratfish and octopuses
Zooplankton and mussels
Galatheid crabs and zoarcid fish
Which statement best describes the differences in species diversity between an ecosystem beginning the process of primary succession and one beginning the process of secondary succession?
Species diversity is much greater in the ecosystem undergoing primary succession because that ecosystem is experiencing a longer period with a lack of competition for space.
No differences in species diversity exist because both ecosystems initially lack living organisms.
Species diversity is much greater in the ecosystem undergoing primary succession because the lack of soil provides a greater area for organisms to claim niches.
Species diversity is greater in the ecosystem undergoing secondary succession because the soil already contains seeds and spores of various species.
The table shows some observations made by four students during a field trip to a nature area.


Which student made observations of a community of organisms?
Student 3
Student 2
Student 4
Student 1
Atmospheric nitrogen has to be combined with other elements, or fixed, in order to be used by plants. Lightning is one way that nitrogen is fixed. When lightning occurs, the extreme heat breaks the bonds in nitrogen molecules, allowing nitrogen to combine with oxygen and form nitrogen oxides. In what way is most of the nitrogen fixed by lightning made available for use by plants?
It is carried by rain to the soil.
It is inhaled and exhaled by birds roosting in trees during rainstorms.
It is incorporated into the exoskeletons of flying insects that eat plants.
It is moved by the wind toward dry areas.
A student performed an investigation in which two ivy plants were planted in two separate containers. One of the containers had earthworms mixed in with the soil, and the other container had soil and no earthworms. The plants were given the same amount of water and exposed to the same amount of sunlight. The student observed that after several weeks of growth, the plant exposed to earthworms appeared to be healthier and exhibited more growth. To conclude that the relationship between the plant and the earthworm is an example of mutualism, the student must perform follow-up investigations that do which of the following?
Determine whether the earthworms damage the soil in any way
Determine whether the other plant in the investigation suffers as a result of not being exposed to earthworms
Determine whether the water given to the plant is unpolluted
Determine whether the earthworms benefit from being with the plant
Hydrothermal vents form deep in the ocean when iron-rich magma is released from openings on the seafloor. These vents spew extremely hot water (400°C) mixed with methane and sulfur. Bacteria that thrive in this hostile environment form the base of a food chain that leads to colonization by tube worms, mussels, and many other life-forms. When a hydrothermal vent becomes inactive and cold, the bacterial community that lives in the hot fluid methane and sulfur dies out. Which organisms most likely succeed the original community in this ecosystem?
Fish that do not need oxygen for cellular respiration
Ocean mammals that tolerate cold and act as top predators in the food chain
B Giant kelp that use sulfur in photosynthesis
Cold-tolerant bacteria that feed on sulfur and iron in the vents
The diagram shows the flow of organic molecules through an ecosystem. One process that occurs in this ecosystem is labeled X, and another process that occurs is labeled Y


Which two processes are identified by the labels X and Y?
X: Adaptation Y: Decomposition
X: Decomposition Y: Respiration
X: Fermentation Y: Nitrogen fixation
X: Respiration Y: Predation
How do an increase in the organic matter in soil and an increase in soil depth affect the population of plants in an area?
Nitrogen-fixing bacteria kill young trees
A Larger plants become the dominant organisms
Grasses become diseased
Mosses replace flowering plants.
Bats eat insects that damage crops and mosquitoes that are vectors for disease. One million bats can eat several tons of insects per night, saving billions of dollars in pesticides yearly. Agricultural and public health scientists are concerned about the spread of white-nose syndrome (WNS). WNS is a result of a fungus that can infect cave-dwelling bats. While bats hibernate during winter months, the fungus covers the bats’ face and wings. WNS has a near 100% mortality rate, and 5.7 million bats have died since the discovery of the fungus in 2006. Many scientists are searching for ways to protect these bats. The relationship between this fungus and bats can best be defined as —
competitive, because both organisms use caves as shelter during the winter
mutualistic, because the relationship involves two distinct species living together
parasitic, because the fungus obtains nutrients and shelter from the bats
commensal, because the bats provide a surface for the fungus to grow
As ecosystems move through the stages of succession, the populations of organisms in them change. Which of the following describes the stage of succession likely to have the most species diversity?
A newly formed volcanic island
A field that is regularly mowed
A temperate forest that has never been cleared by logging
An agricultural field that has not been plowed for one year
Parrotfish are herbivores that are found in coral reefs. To escape predation, a parrotfish will graze with a rabbitfish, which has venomous spines at the end of its pelvic fins. The rabbitfish does not benefit from this relationship. Which type of relationship do the parrotfish and the rabbitfish have in the coral-reef environment?
Mutualistism
Predator- prey
Parasitism
Commensalism
Dead zones are low-oxygen areas that develop on the seafloor. Scientists hypothesize that phytoplankton blooms cause these dead zones. Phytoplankton blooms occur when excess nutrients are introduced by pollution from fertilizers, sewage plants, and the burning of fossil fuels. Which of the following would most likely cause an increase in these contributors to dead zones?
Rainfall patterns that increase freshwater runoff from terrestrial ecosystems
Replacing coal-fired power plants with windmills
Constructing efficient water-recovery and treatment plants
Farming practices that reduce nitrate and phosphate applications
Surtsey is an island located south of Iceland. The island was formed by a volcanic eruption and first appeared in 1963. The table below contains descriptions of changes in the population and diversity of species on Surtsey.


Which of these lists the descriptions in the correct order of ecological succession on Surtsey?
I, II, IV, III
III, I, II, IV
IV, III, I, II
II, IV, I, III
The graph below shows the changes in the number of species in an ecosystem.


Which event was most likely the cause of the changes in species diversity in this ecosystem?
A large volcanic eruption
A flash flood
A small tornado
A migration of locusts
The picture shows a pika, a small mammal found in grassland ecosystems. The vast grasslands of the Tibetan plateau are home to the plateau pika. The numerous pikas are prey for many predators of the grasslands, which serve as a major watershed for much of the area. The watershed drains large quantities of groundwater during the rainy season, or the monsoon season. Pikas have extensive burrows that help drain groundwater rapidly and are used as nesting sites by many bird species. However, many people advocate the eradication of the plateau pikas because they compete with livestock for grass.


Which of these will most likely happen if the plateau pikas are completely removed from the Tibetan plateau grasslands?
The ecosystem will become unstable because the predators will migrate to nearby ecosystems, the birds will nest in nearby trees, and the soils will be aerated by other small mammals.
The ecosystem will become unstable because predators will have fewer prey, the birds will have fewer nesting sites, and the area downriver will become vulnerable to flooding without the burrows to aerate the soil and provide drainage for monsoon rains.
The ecosystem will become more stable because the pika will no longer be there to eat the grasses, the birds will migrate to other ecosystems during nesting season, and the soils will be able to absorb more of the monsoon rains without the pika burrows.
The ecosystem will become more stable because the pika will be replaced by other species of small mammals that can fill the niche, bird species will adapt to nesting aboveground, and the soils will become compacted without the burrows.
An estuary collects sediments from the ocean and rivers that feed into it. The sediments swirl around and then settle to form a mudflat. Eel grass is then established on the mudflat. The ecosystem changes over time and ultimately develops into a salt marsh that contains mangrove trees. Which of the following is likely NOT involved in this example of ecological succession?
The concentration of salt becomes so high that all plant life is destroyed.
The soil becomes so fertile that eel grass is replaced by other plant species.
The roots from plants help stabilize the sediment, keeping it in place.
The rotting remains of plants add to the fertility of the soil.
The rocky material left behind by a retreating glacier forms what is called a moraine. When primary succession occurs on a moraine, which life-forms will help create the soil by breaking down bare rock?
Deciduous trees
Grasses
Insects
Lichens
What describes a pioneer species in an ecosystem?
Species that live in wet conditions.
First species to go extinct.
First colonizers in barren environments.
Most abundant species overall.
Which is a common example of a pioneer species?
Cacti in deserts.
Elm trees in forests.
Lichens growing on bare rock.
Seagrass in oceans.
What is a primary role of pioneer species?
To store water in deserts.
To outcompete other species.
To block sunlight for plants.
To initiate soil formation from rock.
Which habitat is likely to first see pioneer species?
A recently formed volcanic island.
Dense tropical rainforest.
Deep ocean floor.
Established suburban gardens.
Which characteristic do pioneer species often have?
Ability to survive harsh conditions.
High energy requirements.
Long life spans.
Fast reproduction rates.
How do pioneer species affect biodiversity?
They eliminate existing diversity.
They have no effect on biodiversity.
They create conditions for diverse species.
They only support a few species.
What happens to pioneer species as succession progresses?
They are often replaced by other species.
They dominate forever.
They turn into trees immediately.
They die off entirely without impact.
During primary succession, what is the initial substrate or substance?
Established soil with weeds.
Wet mud in swamps.
Bare rock or volcanic ash.
Dense forest litter.
What role do lichens play in relation to pioneer species?
They inhibit other plant growth.
They provide shade for other species.
They break down rocks to form soil.
They need other plants to survive.
Identify the pioneer species below
lichen
algae
grasses
bacteria
rose bush
flowers
evergreen trees
mosses
fungi
apple tree
What is primary succession?
A rapid change in climate conditions.
Succession in lifeless areas without soil.
Succession in areas with existing vegetation.
Succession after a minor disturbance.
Which is an example of primary succession?
A forest regrowing after a fire.
Wetlands forming from a receding glacier.
Grasslands developing after farmland is abandoned.
Lichen growing on bare rock after a volcano.
What event can trigger primary succession?
Volcanic eruption creating new land.
A forest fire destroying existing plants.
Construction of buildings in urban areas.
A severe drought affecting local flora.
After a glacier melts, what changes occur?
Animals move in before plants establish.
Primary succession begins in exposed rock.
Diverse species invade immediately.
Soil forms instantly for plants to grow.
Why are intermediate stages important in succession?
They prevent further changes in species diversity.
They provide habitats for various species.
They indicate permanent ecosystem stability.
They are short-lived and irrelevant.
What can inhibit/prevent secondary succession?
Human activity disrupting the regrowth process.
Infertile soil preventing regrowth.
Natural disasters ending all life.
Pioneer species re-establishing quickly.
What environmental conditions favor secondary succession?
High pollution levels affecting growth.
Complete destruction of the area.
Lack of moisture and sunlight.
Presence of soil and residual organisms.
During succession, what happens to biodiversity?
Only invasive species survive initially.
Biodiversity generally increases over time.
Biodiversity remains unchanged throughout.
All species become extinct at once.
What is the climax community?
A community without any disturbances.
The initial phase of plant growth.
A temporary state of imbalance.
A stable, mature ecosystem after succession.
In which environments is primary succession most likely?
Urban areas with significant human presence.
Bare rock surfaces like volcanoes or cliffs.
Wetlands that are already established.
Dense forests with abundant life.
The table below summarizes key characteristics of four different biomes. Based on the information provided, which biome is correctly matched with its description?

Desert
Tropical Rainforest
Taiga (Boreal Forest)
Temperate Grassland
Using the graph below, which biome has relatively the same temperature each month?

T.R. Forest
Grassland
T.D. Forest
Tundra
Using the graph below, which biome has the highest temperature in July?

T.D. Forest
T.R. Forest
Taiga
Tundra