MB Chapter 20

In terms of + (this member of a species pair benefits from the interaction), - (this member of a species pair is harmed by the interaction), and 0 (this member of a species pair is unaffected by the interaction), predation can be described as a __________ relationship.

+/-

10,000 kcal of producer could support approximately _____ kcal of tertiary consumer.

10

Approximately _____% of the energy at one trophic level is passed on to the next highest trophic level.

5-10%

Assimilation is indicated by the letter(s) _____.

A: Assimilation is the uptake of nutrients into an organism.

Nitrification is indicated by the letter(s) _____.

B: Nitrification is the conversion of organic nitrogen-containing compounds to nitrites and nitrates.

Where do plants get the carbon they use to make organic molecules?

CO2

Nitrogen-fixing bacteria is(are) indicated by the letter(s) _____.

D and E: Both of these pointers are indicating nitrogen-fixing bacteria. Nitrogen fixation is the conversion of nitrogen to a form that plants can use.

What name is given to the process by which detritivores return carbon to the atmosphere?

Decomposition: the conversion of organic molecules into inorganic molecules, results in the release of carbon dioxide into the atmosphere.

Which one of these is a nitrite?

NO2-

Which one of these is a nitrate?

NO3-

Why do toxins accumulate at such high levels in carnivores?

The biomass at any given trophic level is accumulated from a much larger toxin-containing biomass ingested from the level below.: Remember that only 10% of the energy is transferred from one level to the next. Thus, a top carnivore quickly accumulates the largest amounts of toxin.

Which of these removes carbon from the atmosphere?

algae

Nitrifying bacteria convert _____ to _____.

ammonium ... nitrites

Aquatic nitrate pollution can result in _____.

an algal bloom that, when the algae die and are decomposed by bacteria, leads to hypoxia and the death of fish

Which of these are the two major sources of nitrate pollution in rivers?

animal waste and fertilizers

The use of living organisms to detoxify polluted ecosystems is called _____.

bioremediation: Restoration projects have the broad goal of returning ecosystems to their natural state.

An ecosystem is unlikely to be limited by the supply of _____ because it is obtained from the air.

carbon

What element is found in all organic compounds?

carbon

_____ are secondary consumers.

carnivores

What is the name of the process by which organisms convert the carbon in organic compounds into carbon in carbon dioxide?

cellar respiration

All the organisms in a particular area make up a(n) __________

community

Humans and sharks both eat fish. Which of these terms applies to the relationship between the human and the shark?

competition

The study and protection of biological diversity is a field called __________.

conservation biology

Detritus is composed of _____.

dead organic matter and excreted wastes

An earthworm that feeds on the remains of plants and animals is acting as a _____.

detritivore

According to the principle of interspecific competition, two species cannot continue to occupy the same __________.

ecological niche

Which of these provides your body with energy?

fats

Plants use _____ as a source of energy.

light

Edge species __________.

may require conditions found in both of the bordering ecosystems: The cowbird is an edge species that feeds in open fields and parasitizes the nests of other bird species in the forest.

Which of these is NOT an organic molecule?

minerals

Humans who have pets tend to be healthier than humans who do not have pets. Which of these terms applies to the relationship between a human and a pet?

mutualism: both members of the species pair benefit; in this case the human is healthier and the pet is getting room and board.

Denitrifying bacteria convert _____ to _____.

nitrates to nitrogen gas

_____ removes nitrogen from the atmosphere.

nitrogen fixation

Biogeochemical cycles are crucial to ecosystem function because __________.

nutrients and other life-sustaining molecules are in limited supply and must be continually recycled

The energy flow through the trophic levels of an ecosystem is represented as a pyramid because __________.

only about 10% of the energy at each trophic level is available at the next level

Which of these terms applies to the relationship between a dog and a blood-sucking tick?

parasitism: The tick benefits at the expense of the dog; the dog is the host and the tick is the parasite.

A human eats a deer. Which of these terms applies to the relationship between the human and the deer?

predation

A cow eating grass is an example of a _____.

primary consumer

In an ecosystem, phytoplankton are _____.

producers

Biodiversity hot spots are __________.

regions with the potential for high levels of extinction

Consider the following segment of a food web: Snails and grasshoppers eat pepper plants; spiders eat grasshoppers; shrews eat snails and spiders; and owls eat shrews. The shrew occupies the trophic level(s) of __________.

secondary and tertiary consumers

When a human eats a steak, the human is acting as a _____.

secondary consumer

Which of the following describes the number of different species in the community?

species richness

A human who just ate a hamburger is eaten by a shark while swimming. The shark is acting as a _____.

tertiary consumer

Which of the following is an example of primary succession?

the colonization of a newly formed volcanic island: This is the succession from a barren, lifeless area to a community of organisms.

The energy for nearly every organism in almost every ecosystem ultimately comes from _____.

the sun

Which of the following impacts the nitrogen cycle?

the use of large amounts of inorganic fertilizers

An organism's "trophic level" refers to _________

what it eats