human population review

The concentration of H+ ions in a solution with a pH value of 4 is how many times as great as the concentration of H+ ions in a solution with a pH value of 7?

1,000

If there are 10,000 kilocalories of energy available at the producer level, how many kilocalories will be available at the tertiary level?

10

The process by which a soil nutrient is reduced and released to the atmosphere as a gas. Correct match:

:Denitrification

Represents the biotic potential of the species.

A

How does an algal bloom affect the oxygen content of the water?

An algal bloom will cause the oxygen content in the water to decrease, leading to hypoxic conditions.

Plant roots absorb ammonium ions and nitrate ions for use in making molecules such as DNA, amino acids, and proteins. Correct match:

Assimilation

Country with the greatest percentage of land area affected by desertification Correct match:

Australia

A field is abandoned, and an invasive plant that can live in nutrient-poor soil moves into the field. If the land is later cleared of this invasive species and it is discovered that the soil has an abundance of nitrogen compounds, what conclusion can best be made?

Bacteria in soil and in root nodules converted free nitrogen into nitrogen compounds.

Represents the growth of a population predicted by the logistic model

C

How does the burning of fossil fuels contribute to the net increase in atmospheric carbon?

Carbon that has been sequestered underground is added to the carbon cycling between the atmosphere and the biosphere.

Organisms can form several types of symbiotic relationships. From the descriptions, determine if each of the symbiotic relationships is an example of commensalism, mutualism, or parasitism. · Hermit crabs protect themselves from predators by living in shells discarded by snails. · Ticks attach to humans in order to eat human blood. Ticks can also infect humans with Rocky Mountain spotted fever and Lyme's disease. · The coralroot orchid is a reddish color and is unable to photosynthesize. These orchids take carbohydrates from pine trees through connections formed between their roots and the roots of the pine trees. · The bullhorn acacia grows special tissues in which ants live. The ants find a safe place to live and attack any animals that attempt to graze on the acacia. · The Leucochloridium worm infects snails and is able to control the snail's behavior, creating a zombie-like snail. The worm forces the snail to attract predators to itself so that the worm is eaten and passed to its next host. · On the Galapagos Islands, there are finches that remove parasitic insects from tortoises. The finches gain a meal and the tortoises are ridded of parasites. · Cattle egrets follow cattle and other large grazing animals and eat the insects stirred up by cattle's hooves.

Commensalism Correct answer:Cattle egret and cattle Correct answer:Hermit crab and snails Mutualism Correct answer:Galapagos tortoise and finches Correct answer:Bullhorn acacia and ants Parasatism Correct answer:Coralroot orchid and pine Correct answer:Leucochloridium worm and snail Correct answer:Ticks and humans

The rapid rate of this process in tropical forests results in low-nutrient soils.

Decomposition

Nitrate ions and nitrite ions are converted into nitrous oxide gas and nitrogen gas (N2).

Denitrification

Which of the following best illustrates the concept of the tragedy of the commons?

Depletion of an aquifer by regional farmers.

Which of the following is the best illustration of the tragedy of the commons?

Depletion of fishing stocks in the North Atlantic

Represents the maximum number of individuals that can be supported by a particular ecosystem on a long-term basis.

E

n Mediterranean climate regions like portions of California, a wetter-than-normal winter often leads to greater severity of fires the following summer. This seeming paradox occurs because increased rains leads to

Greater accumulation of chaparral biomass

You are on a town committee formed to determine the borders for a new local nature park. You explain that according to the theory of island biogeography, if the committee wishes to promote species richness it shouldI. increase the size of the park.II. decrease the distance between the park and a nearby protected forest.III. isolate the park by building a wall around its borders.

I and II

Which is NOT a factor in the theory of island biogeography?

Islands farther from the continent have more species due to increased speciation.

Ammonia is converted to nitrite, then to nitrate. Incorrect match:

Nitrification

The arrow represents the approximate pH of which of the following? (ph of about 6)

Normal rainfall , Not Selected

Photosynthesis is the major source of which of the following gases in Earth's atmosphere?

O2

The process in which glucose is synthesized by plants

Photosynthesis

Of the following, which is the best example of reclamation of disturbed lands?

Restoring vegetation to an area that has been mined.

Country with the largest area of boreal forests

Russia

Which of the following is the best example of a keystone species?

Sea otter

A one-hectare pond is sampled in early September. The sample yields 1 small catfish, as well as 17 benthic invertebrates that represent 10 species. If the pond is resampled a year later, which of the following would best indicate that the pond had been adversely affected by adjacent development?

The biodiversity of the pond has decreased

A one-hectare pond is sampled in early September. The sample yields 1 small catfish, as well as 17 benthic invertebrates that represent 10 species. Which of the following can be estimated from the sample for the invertebrates in the pond?

The species richness

Which of the following is true of farm-raised salmon?

They are often infected with parasites and sea lice.

Why do introduced species often become pests?

They displace native species.

Which of the following best helps to explain why phosphorus is often a limiting factor in many ecosystems?

Under many conditions, phosphorus forms stable insoluble compounds.

Country with the largest area of temperate deciduous forest.

United States of America

Traveling southward from the Arctic regions of Canada to the tropics of Panama, one passes through several biomes -- tundra, coniferous forest, temperate deciduous forest, and tropical rain forest. This pattern of change in vegetation is primarily the result of

an increase in both mean annual temperature and mean annual precipitation

Which process of the nitrogen cycle involves the conversion from nitrate (NO3-) to nitrous oxide (N2O) and nitrogen gas (N2)?

denitrification

Which is NOT likely to characterize pioneer plant species involved in primary succession?

grows slowly, lives a long time

Which is NOT an example of two organisms in a mutualistic relationship?

humans and the protozoa that cause malaria

The factor that likely poses the greatest threat of extinction worldwide is

increasing loss of habitat.

Ecologist Paul Ehrlich likened species in a community to rivets holding together an airplane: airplanes can lose some of their rivets with no ill effects, but may suffer catastrophic failures if one too many are lost. We could extend this analogy to state that some rivets are so crucial that they must be retained for the integrity of the airplane. These "crucial" rivets represent

keystone species.

In a particular freshwater ecosystem, phosphorous is required to sustain plant growth. Regardless of the amounts of nitrogen or other mineral nutrients in the lake, aquatic plants in this system have been unable to mature without an increase in phosphorous. In this example, phosphorous can be described as a

limiting nutrient.

When interspecific competition occurs between two species with the same realized niche

one species will perform better and drive the other to extinction.

The waste product in photosynthesis is

oxygen.

The Mauna Loa volcano of Hawaii frequently releases lava that kills many surrounding plants. After the lava hardens, plant life returns to the mountainside. This is known as

primary succession

Over 12,000 years ago at the end of the last ice age, the Laurentide Ice Sheet began melting and retreating in North America. The melt water and glacial erosion created glacial lakes across the northern half of the United States. Following the formation of a glacial lake, algae and phytoplankton in the lake begin to grow and reproduce rapidly. This is an example of

primary succession.

Choose the correct sequence for energy flow within an ecosystem:

producers→ herbivores→ carnivores→ scavengers

What law explains energy loss within an ecosystem?

second law of thermodynamics

Population biologists are concerned about introduced species such as the zebra mussel in North America because

the introduced species compete for resources more effectively than native species.

In the past century, overgrazing by cattle and sheep has caused sagebrush to expand its range over the Colorado Plateau grasslands. This phenomenon indicates that

the range of sagebrush is normally limited by competition with grasses.