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31

increases in NPP are positively correlated with

increases in net secondary productivity.

32

At higher latitudes, productivity is limited by

shorter periods of sunlight and lower temperatures

33

In deserts, NPP is constrained by

lack of precipitation.

34

Tropical areas have high NPP due to

intense sunlight, warm temperatures, abundant precipitation, and rapidly recycled nutrients.

35

Ecosystems that receive more than 3 m of precipitation experience a decline in NPP because

nutrients leach from the soil.

36

Rates of decomposition are reduced in

waterlogged soils.

37

Grasslands, forests, and tundra habitats all experienced increased NPP when

nitrogen and phosphorus were added.

38

In addition to temperature, precipitation, and nutrients, aquatic ecosystems are also limited by

light.

39

Within aquatic ecosystems that have similar temperatures and light levels

NPP is largely limited by nutrients

40


Diatoms are often limited by

by silicon and iron

41

chart composed of stacked rectangles representing the amount of energy (i.e., pyramid of energy) or biomass (i.e., pyramid of biomass) in each trophic group.

Trophic pyramid

42

and only small amounts of terrestrial plant material are consumed in what systems

terrestrial systems

43

most producers are tiny algae that rapidly reproduce and are quickly consumed in what ecosystems

aquatic ecosystems

44

creates an inverted biomass pyramid.

standing crop of algae is much smaller than that of consumers

45

the percentage of energy or biomass in a trophic level that is consumed by the next higher trophic level

Consumption efficiency

46

the percentage of consumed energy that is assimilated (i.e., material that is not egested, such as bones).

Assimilation efficiency

47

primary consumers tend to have lower efficiencies than secondary consumers

because prey tissues are more digestible than plant tissues.

48

the percentage of assimilated energy that is used for growth and reproduction; the percentage of assimilated energy that remains after respiration.

Net production efficiency

49

net production efficiency can be as low as 1%.for what type of animals

active homeothermic animals

50

active homeothermic animals spend energy to

maintain body temperature, move, circulate blood, and osmoregulate

51

net production efficiency can be as high as 75%.

For sedentary poikilothermic animals

52

the percentage of net production from one trophic level compared to the next lower trophic level.

Ecological efficiency (food chain efficiency):

53

the percentage of net production from one trophic level compared to the next lower trophic level.

Ecological efficiency (food chain efficiency):

54

ecological efficiency is usually low, ranging from

5% to 20%;

55

10% is used as a rule of thumb for

ecological efficiency

56

Low ecological efficiencies make it difficult to have long food chains because

there is little energy to support higher trophic levels

57

how many trophic levels fo aquatic ecosystems typically have

5

58

how many trophic levels do terrestrial ecosystems usually have

3-4

59

terrestrial plants are not easily consumed because

they contain defense compounds

60

aquatic algae is easily consumed because

they are small and have no defenses