Ecosystems

Question 1

ecosystem

Answer 1

All the organisms that live in a geographic area, together with the nonliving (abiotic) components that affect or exchange materials with the organisms; a community and its physical environment.

Question 2

What are the four components of an ecosystem?

Answer 2

the abiotic environment, primary producers, consumers, decomposers

Question 3

primary producer

Answer 3

Any organism that creates its own food by photosynthesis or from reduced inorganic compounds and that is a food source for other species in its ecosystem.

Question 4

autotroph

Answer 4

Any organism that can synthesize reduced organic compounds from simple inorganic sources such as CO2 or CH4. Most plants and some bacteria and archaea are autotrophs

Question 5

net primary production

Answer 5

In an ecosystem, the total amount of carbon fixed by photosynthesis over a given time period minus the amount oxidized during cellular respiration.

Question 6

biomass

Answer 6

The total mass of all organisms in a given population or geographical area; usually expressed as total dry weight.

Question 7

heterotroph

Answer 7

consumer

Question 8

primary consumers

Answer 8

An herbivore; an organism that eats plants, algae, or other primary producers.

Question 9

secondary consumers

Answer 9

A carnivore; an organism that eats herbivores

Question 10

tertiary consumers

Answer 10

In a food chain or food web, organisms that feed on secondary consumers.

Question 11

decomposers or detrivores

Answer 11

An organism whose diet consists mainly of dead organic matter (detritus). Various bacteria, fungi, and protists are detritivores.

Question 12

detritus

Answer 12

A layer of dead organic matter that accumulates at ground level or on seafloors and lake bottoms.

Question 13

gross primary productivity

Answer 13

In an ecosystem, the total amount of carbon fixed by photosynthesis, including that used for cellular respiration, over a given time period.

Question 14

gross photosynthetic efficiency

Answer 14

The efficiency with which all the plants in a given area use the light energy available to them to produce sugars.

Question 15

Why is photosynthetic efficiency low?

Answer 15

• Plants in temporate biomes have drastically reduced photosynthetic rates in winter.
• If conditions get dry in summer, stomata close to conserve water, photosynthesis slows due to lack of water
• pigments only absorb only a fraction of total energy

Question 16

trophic level

Answer 16

A feeding level in an ecosystem.

Question 17

decomposer food chain

Answer 17

An ecological network of detritus, decomposers that eat detritus, and predators and parasites of the decomposers.

Question 18

primary decomposers

Answer 18

A decomposer (detritivore) that consumes detritus from plants.

Question 19

grazing food chain

Answer 19

The ecological network of herbivores and the predators and parasites that consume them.

Question 20

food webs

Answer 20

Any complex pathway along which energy moves among many species at different trophic levels of an ecosystem.

Question 21

What is the difference in primary producer consumption in oceans as opposed to land?

Answer 21

In oceans more biomass is consumed

Question 22

How does biomass change from trophic level?

Answer 22

Higher trophic level less biomass produced

Question 23

What is the general efficiency of biomass transfer from one trophic level to the next?

Answer 23

10%

Question 24

Which are more efficient in biomass production? Large mammals vs. small mammals / ectotherms vs. endotherms

Answer 24

Large mammals, less heat loss/ Ectotherms less energy in maintenance

Question 25

trophic cascade

Answer 25

A series of changes in the abundance of species in a food web, usually caused by the addition or removal of a key predator.

Question 26

biomagnefication

Answer 26

In animal tissues, an increase in the concentration of particular molecules that may occur as those molecules are passed up a food chain.

Question 27

Where are the terrestrial ecosystems with the highest productivity?

Answer 27

In the wet tropics

Question 28

How much of earth’s biomass do humans use?

Answer 28

1/4

Question 29

biogeochemical cycle

Answer 29

The pattern of circulation of an element or molecule among living organisms and the environment.

Question 30

humus

Answer 30

The completely decayed organic matter in soils.

Question 31

What is the key for the decomposition cycle?

Answer 31

converts organic matter into inorganic

Question 32

What two factors have an effect on decomposition rate?

Answer 32

1) abiotic conditions such as oxygen availability, temperature and precipitation
2) quality of the detritus as a nutrient source for decomposers

Question 33

What are the main factors in detritus quality?

Answer 33

nitrogen, absence of lignans

Question 34

watersheds

Answer 34

The area drained by a single stream or river.

Question 35

global water cycle

Answer 35

The movement of water among terrestrial ecosystems, the oceans, and the atmosphere.

Question 36

water table

Answer 36

The upper limit of the underground layer of soil that is saturated with water.

Question 37

global nitrogen cycle

Answer 37

human source=natural source

Question 38

global carbon cycle

Answer 38

The movement of carbon in relation to the earth system

Question 39

phenology

Answer 39

The timing of events during the year, in environments where seasonal changes occur.

Question 40

secondary production

Answer 40

The total amount of new body tissue produced by animals that eat plants. May involve growth and/or reproduction.