Chapter 37 Quiz

The following equation is for trophic level transfer efficiency:(production at present trophic level/production at past trophic level) × 100If primary producers produce 1,600 kcal/m2 and primary consumers have 800 kcal/m2, what is the trophic level transfer efficiency?

50

Using the flow chart showing carbon flow in a grassland ecosystem, how much carbon, in grams per meter squared, is released into the atmosphere as a result of the metabolic activity of herbivores? Give your answer to the nearest whole number.

60 g/m2

There are four trophic levels in a food chain, and the amount of energy at the trophic level of the primary producer is 33,000 kcal/m2. What most likely represents the amount of energy of the tertiary consumer?

75 kcal/m2

What is a potential consequence of excess phosphorus and nitrogen in an ecosystem?

A dead zone could be produced from depleted oxygen.

How do agricultural animals such as cattle raise atmospheric carbon levels? What is a side effect?

Agricultural animals increase the amount of greenhouse gases by producing carbon dioxide and methane, so they contribute to global warming.

In an effort to enter all identified species on Earth into a digital catalog, scientists are preparing a unique tag for each species. Algorithms have been generated to create unique tags. Which algorithm is best suited for the task?

An algorithm that creates 1.5 million to 2 million unique tags

If scientists wanted to monitor a desert food chain, what type of model might they develop and why?

An analytical model would be ideal because they can address simple, linear ecosystem components that are mathematically complex.

What term describes the use of mathematical equations in the modeling of linear aspects of ecosystems?

Analytical modeling

Why do scientists more commonly analyze net primary productivity compared with gross primary productivity?

As respiration and heat loss uses energy of primary producers, net primary productivity is what is actually available to primary consumers.

Students analyze pollen grains and fern spores recovered from sediments taken below and above the Cretaceous-Paleogene boundary. Their results are summarized in the graph. Which conclusion can be drawn from the graph regarding the impact of the mass extinction that took place at the K-Pg boundary on plants?

Based on their reduced pollen counts found in the samples, the mass extinction event clearly reduced the number of ferns and angiosperms.

Why does this figure show a higher value of gross productivity for the decomposers than the tertiary consumers?

Because tertiary consumers only consume secondary consumers whereas decomposers consume dead components of each trophic level

What is the weight of living organisms in an ecosystem at a particular point in timeknown as?

Biomass

What type of pyramid is considered the most representative of ecosystem structure?

Biomass

This graph shows the movement northward of wintering grounds of North American bird species. The trend closely mirrors the increase in average winter temperatures. What problem could develop from birds using farther north areas?

Birds that arrive too early may be killed by the occasional abrupt cold spell.

Which activity will result in major habitat loss?

Building a dam that will flood a large plain

What forms of life use inorganic molecules as an energy source and are found in areas where sunlight is unavailable?

Chemoautotrophs

If a scientist constructs a flow chart to depict the interactions among species in an estuary, what kind of model is she creating?

Conceptual modeling

Although producers are essential for energy to flow into an ecosystem, consumers also have important roles. What might happen in an aquatic system with excess consumers relative to producers?

Consumers would deplete the abundance of producers.

What is produced by eutrophication via excess nitrogen where a hydrologic reservoir lacks normal flora and fauna?

Dead zones

In a microcosm experiment using fish tanks to mimic a lake environment, an increase in the number of stickleback species would increase the dissolved organic carbon particle size. How could this affect primary producers in the ecosystem?

Decrease abundance

Urban designers included wetlands and lagoons connected to a water treatment plant to a new subdivision of homes. The designers would have most likely applied which principle of conservation to their plans?

Ecosystem service

How does the amount of food that endotherms and ectotherms consume compare with their net production efficiency (NPE)?

Endotherms use more energy compared to ectotherms due to energy loss from heat production.

What most strongly influences how much carbon is present in a given location?

Exchange of carbon between the atmosphere and water

What type of ecosystem is the rarest on Earth, among both terrestrial and aquatic ecosystems?

Freshwater

Two genera of birds exist side-by-side on an island. Genus A is characterized by a few species of similar genetic material. Genus B contains different species of birds with a wide variety of genetic traits. After a volcanic explosion changes the ecosystem, which genus has the highest probability of surviving the disaster?

Genus B, which has greater genetic diversity and is more likely to have traits that confer an advantage in the new environment

Humans are very active in modifying ecosystems worldwide. If a new set of buildings on the edge of a forest blocks sunlight from reaching the majority of one part of the forest, what might happen to that part of the forest?

Herbivores would occur in low abundance.

Exotic predator species are especially threatening to what kind of ecosystem?

Islands

This figure depicts energy exchange through trophic levels. Which level represents the primary producers?

Level D

Name one natural and one human-related disturbance. Why are they of concern to conservationists?

Lightning is a type of natural disturbance whereas pollution is a human-related disturbance. Both are of concern to conservationists because they alter ecosystems.

The island of Madagascar is located in the tropics 300 miles east of the coast of Africa, from which it separated 165 million years ago. It is characterized by a large number of endemic species.

Madagascar has been isolated geographically and species evolved there without interaction with outside influences.

Wolves are a keystone species in the Yellowstone National Park. What would happen if they were hunted to extinction?

Many species would disappear and the elk population would initially increase.

A scientist wants to analyze how grazing by deer alters plant species composition in a forest and sections off a portion of the forest for observation and analysis. What type of system is the scientist using?

Mesocosm

What is a recreated ecosystem in a laboratory environment known as?

Microcosm

What is the process whereby nitrogen is brought into organic molecules?

Nitrogen fixation

If you examined predator-prey relationships within an ecosystem and noticed that the removal of predators also resulted in the die-off of herbivores, what would you suspect occurred?

Overeating by herbivores could have caused depletion of the primary producers, leaving the herbivores without enough food.

Producers and consumers are necessary for ecosystem function and for energy to pass through an ecosystem. What might happen in an aquatic system with excess producers relative to consumers?

Oxygen depletion would result in die-off.

One of the key concerns about global climate change is excess amounts of carbon being released into the atmosphere. There are, however, some ways in which carbon can be sequestered from the atmosphere. Which natural process promotes carbon sequestration?

Photosynthesis by plants

What are usually the primary producers in an ocean grazing food web?

Phytoplankton

Grizzly bears and black bears have a varied diet and hunting grounds. On the other hand, polar bears feed mostly on seals. They walk on the sea ice and wait by breathing holes for seals to emerge from the water for fresh air. Which animal would be most affected by the melting of sea ice in Alaska?

Polar bears

A chain within the food web in the Arctic Ocean is shown.phytoplankton -> zooplankton -> arctic char/cod -> ringed seal -> polar bearA chain within the arctic food web on land is shown.lichen/shrub -> caribou/hare/small rodent -> fox/lynx/bird of preyIf polar bears move to land to hunt due to loss of sea ice, what will happen to the balance of the food web? Group of answer choices

Polar bears, being top predators, will edge out the other consumers without gaining enough calories themselves.

Which factor is present in an ecosystem that performs the same role as a pesticide?

Presence of insect predators

Energy is a fundamental component in an ecosystem and is contributed by the primary producers. How can light energy, in turn, support the consumers of an ecosystem?

Primary producers convert light energy to chemical energy using photosynthesis and consumers gain energy by feeding on them or on other consumers that have consumed these producers.

If you wanted to measure gross primary productivity in a terrestrial ecosystem, what would you measure?

Rate of energy incorporation by plants

What is a mechanism by which phosphorus is released into the environment?

Rock weathering

What law of chemistry determines how much energy can be transferred when it is converted from one form to another because energy is lost with each transformation?

Second law of thermodynamics

Where are coral reefs found?

Shallow ocean water

The average temperatures varied during the Pleistocene as glaciation periods were followed by warm intervals. Using the graph and your existing knowledge, what happened to woolly mammoths and other cold-adapted megafauna 10,000 years ago to cause their extinction?

Sudden increase in temperature and over-hunting by humans led to their extinction.

What is the term for freshwater that flows from rain or melting ice in the hydrologic cycle?

Surface runoff

The food web for a meadow habitat occupies 25.6 km2. The primary producers' biomass is uniformly distributed throughout the habitat and totals 1,500 kg/km2. Developers have approved a project that will permanently reduce the primary producers' biomass by 50 percent and remove all rabbits and deer. What is the most likely result at the completion of the project?

The biomass of coyotes will be dramatically reduced.

Why are mesocosm and microcosm experiments NOT considered to represent the true nature of ecosystems?

The ecosystem is either recreated or partitioned in both types of experiments, which may alter the dynamics of the ecosystem the experiments are aiming to analyze.

If an ecosystem is considered to be highly resilient, what can be inferred about that ecosystem?

The ecosystem recovers quickly from disturbance.

Backpackers returning from a long trip abroad are stopped by customs and asked whether they brought back plants, flowers, or fruit from their trip location. Their fruit bought at a local market is confiscated. What is the most likely reason why the fruit was confiscated?

The fruit may introduce new exotic pests that threaten local plants.

Students are sorting fossils of angiosperm pollen grains, some recovered from layers below the Cretaceous-Paleogene boundary and some from layers above the Cretaceous-Paleogene boundaries. The pollen grains are sorted by morphology. The results are summarized in a table. Can you explain the results?

The mass extinction that took place at the Cretaceous-Paleogene boundaries reduced the total number of organisms, shown by the presence of fewer pollen grains, and led to a loss of diversity, as shown by the presence of fewer shapes.

Why are the numbers of primary producers smaller than the number of primary consumers in the English Channel ecosystem?

The primary producers have a low turnover rate.

Compare grazing and detrital food webs. Why would they both be present in the same ecosystem?

The primary producers of detrital food webs are decomposers whereas those of grazing food webs are photosynthetic. Both primary producers support different components of the ecosystem.

What is nitrogen fixation, and why it is important to agriculture?

The process of nitrogen being incorporated into organic molecules is called nitrogen fixation. It improves agricultural production as nitrogen is required by plants for nucleotide and protein formation.

Different varieties of potatoes are known to thrive at different altitudes. What could be the related benefit of maintaining the diversity of potato plants?

The range of usable land is extended.

This figure shows a food web of an ecosystem. What would happen to the food web if all of the species of the entire row B was wiped out by a natural disaster such as an oil spill? Why?

The tertiary consumers would die out due to lack of food and this could potentially lead to collapse of the entire food web.

Compare the three types of ecosystem pyramids and how well they describe ecosystem structure. Which ones can be inverted? For each, what is a specific example of an inverted pyramid?

The three types of ecosystem pyramids are pyramids of energy, number, and biomass out of which number and biomass pyramids can be inverted. Examples of inverted pyramids of number and biomass are temperate forests in summer and phytoplankton in the English Channel, respectively.

Scientists are evaluating an island ecosystem to be upgraded to a hot spot of biodiversity. They conduct field research on the species that populate the area. Their final assessment on the biodiversity of the ecosystem will be based on which estimate?

The total number of species in an ecosystem

Which factor explains why, in general, temperate and polar regions have less biodiversity than tropical regions?

The tropical regions contain more micro-ecosystems.

Why does grouping terrestrial organisms into biomes obscure diversity?

There is variation within different types of biomes that biome categorization does not capture.

Studies on stickleback fish revealed that the presence of two species of stickleback reduced the amount of algal blooms relative to the presence of one species of stickleback in a microcosm experiment. How does this occur?

This occurred as the presence of two species caused an increase in dissolved organic carbon molecule size, which blocked the penetration of light in water and prevented algal photosynthesis.

Findings from layers dating to the Cambrian geological period show an appearance of many new organisms in addition to older forms of life. The Cambrian explosion corresponds to a time where —

new species radiated from existing species