lecture 22- ecosystems Flashcards

1
Q

what are the two fundamental processes of an ecosystem

A

energy flow
nutrient cycling

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2
Q

is energy flow 100% efficient

A

no energy is always lost as heat

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3
Q

what is energy flow

A

energy entering as light exits as heat
passing through primary producers
then primary consumers
then secondary consumers

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4
Q

how does decomposition relate to trophic levels

A

it connects them all

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5
Q

how does decomposition work

A

bacteria and fungi recycle nutrients/organic matter (fungi produce exoenzymes)

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6
Q

how does energy flow

A

one way
in and out

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7
Q

what are the four trophic levels composed of

A

first: primary producers
second: primary consumers
third: secondary consumers
fourth: tertiary consumers

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8
Q

what type of organism is a primary producer

A

green plant

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9
Q

what type of organism is a primary consumer

A

herbivores/omnivores

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10
Q

what type of organism is a secondary consumer

A

carnivores/omnivores

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11
Q

what type of organism is a tertiary consumer

A

second level carnivore

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12
Q

what are decomposers also called

A

saprotrophs

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13
Q

what is a food chain

A

ladder of organisms and what they eat (single animal eats a single plant, that animal is eaten by a single other animal)
simple and rare in nature

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14
Q

what is a food web

A

interconnected web of animals and all the food they eat (carnivores eat more than one prey)
complex and more accurate

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15
Q

what is biomass

A

chemical energy stored in an organism

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16
Q

what is primary production

A

amount of energy that autotrophs can incorporate in their biomass

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17
Q

what is GPP

A

gross/total primary production in the plants

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18
Q

what is the NPP

A

net primary production
chemical energy available to consumers
GPP - R

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19
Q

what is R

A

energy used by primary producers (cellular respiration for example)

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20
Q

what energy is available to secondary consumers

A

chemical energy stored by the herbivores’ biomass

21
Q

what is a limiting nutrient

A

element that must be added for primary production to increase in an area

22
Q

what is the limiting nutrient in aquatic ecosystems

A

nutrients such as nitrogen, phosphorous, iron

23
Q

what is the limitation in terrestrial ecosystems

A

temperature, sunlight, availability of water

24
Q

what is evapotranspiration vs annual evapotranspiration

A

amount of water transpired by plants and evaporated from landscape
amount of water annually transpired by plants and evaporated from landscape

25
Q

relation between primary production and evapotranspiration and why

A

more evapotranspiration = more primary production
more water and sunlight = more primary production = more evapotranspiration

26
Q

what are the best conditions for terrestrial ecosystems

A

warm and humid environments (tropical rainforests)

27
Q

what is the disadvantage of a warm and humid ecosystem

A

nutrient cycle is very fast (decomposition is fast) so the soil is nutrient poor/nutrients dont stay in the soil long
little organic matter accumulation

28
Q

what is the secondary production

A

amount of chemical energy is consumer’s food that is converted to their own biomass during a given period of time

29
Q

where does the majority of the energy consumed by organisms go

A

feces

30
Q

how does energy transfer through trophic levels

A

since only a small % of the energy is used for growth (and can be available to the next level)
the next level only gains about 10% of the energy of the last level so there is less and less energy per level and the organism needs to eat more to gain it

31
Q

what is the range of trophic efficiency

A

5-20%

32
Q

why is energy lost at each trophic level

A

indigestible substances
chemical energy in carbon compound bonds is usually lost as heat
energy is always lost as heat (movement)

33
Q

why do toxins accumulate in the environment

A

they are extremely stable

34
Q

how do toxins accumulate in organisms

A

it the organism doesnt break down the toxin it gets stored in fatty tissue and accumulates

35
Q

what is bioaccumulation

A

built up toxin in organism’s body

36
Q

what is biomagnification

A

increase in concentration as it passes from one trophic level to the next

37
Q

what do nutrients cycle through

A

from organism to another
from organism to environment and back

38
Q

what is nitrogenase

A

enzyme used in nitrogen fixation (anaerobic)

39
Q

what is nitrogen fixation and what mainly does it

A

conversion of nitrogen gas to ammonia and ammonium by free living and mutualistic nitrogen fixers
bacteria

40
Q

what is the carbon cycle

A

carbon enters plants as CO2
cellular respiration, combustion and erosion return C to environment

41
Q

steps of the water cycle

A

precipitation (atmosphere to land)
evaporation (land to atmosphere)
transpiration (plants to atmosphere)
runoff to ocean
percolation through soil (ground water)

42
Q

what is nutrient cycling regulated by

A

vegetation

43
Q

what does internal cycling within an ecosystem do

A

conserve most of the mineral nutrients

44
Q

lack of vegetation?

A

more soil erosion = more runoff = less nutrients = more eutrophication

45
Q

how do humans disrupt the nutrient cycles

A

add new materials to ecosystems
move nutrients form one part of biosphere to the other (agriculture and run off)
release compounds in the air (burning fossil fuels)

46
Q

forms of restoration ecology

A

bioremediation
biological augmentation

47
Q

what is bioremediation

A

using living organisms to detoxify or remove toxins from polluted ecosystems
prokaryotes, fungi, plants

48
Q

what is biological augmentation

A

using living organisms (often native to land) to re establish the nutrient cycle into the ecosystem