chapter 42: ecosystems and energy

Question 1

what is an ecosystem?

Answer 1

consists of all the organisms living in a community, as well as the abiotic factors with which they interact

Question 2

what are some examples of abiotic factors that affect ecosystem?

Answer 2

1) nutrients
2) temperature
3) salinity
d) weather
e) climate
f) precipitation
g) terrain
h) rocks
i) pH
j) sunlight

Question 3

what two main processes do all ecosystems have?

Answer 3

energy flow and chemical cycling

Question 4

what happens to the energy in an ecosystem?

Answer 4

no matter what ecosystem we look at, there is energy flow. the energy is transferred from organism to organism through consumption. ultimately, a large portion of the energy is given off as heat, which relates to the second law of thermodynamics

Question 5

where does the energy for an ecosystem come from?

Answer 5

the sun

Question 6

can a cycle go on without a continuous input of energy?

Answer 6

no

Question 7

what happens to chemicals/ elements/ nutrients in an ecosystem?

Answer 7

they are constantly being cycled around. they get transferred and transformed.

Question 8

what is the first law of thermodynamics?

Answer 8

energy cannot be created or destroyed, only transferred or transformed

Question 9

what is the second law of thermodynamics?

Answer 9

every exchange of energy increases the entropy of the universe

Question 10

what is the law of conservation of mass?

Answer 10

matter cannot be created or destroyed.

Question 11

what are sinks?

Answer 11

places where nutrients and/or energy can be stored for a long time

Question 12

what are autotrophs?

Answer 12

autotrophs build molecules themselves using photosynthesis or chemosynthesis as an energy source. they are always the base of the pyramid

Question 13

what are heterotrophs?

Answer 13

they depend on the biosynthetic output of other living organisms.

Question 14

what is biosynthetic output?

Answer 14

stuff made by living organisms

Question 15

what is the order energy flows from in a food pyramid?

Answer 15

from autotrophs / primary producers -> primary consumers/ herbivores -> secondary consumers / carnivores -> tertiary consumers / carnivores -> quaternary consumers

Question 16

why are the terms herbivores and carnivores not used as much?

Answer 16

because they can be omnivore instead of just herbivore or carnivore

Question 17

can organisms be part of two trophic levels?

Answer 17

yes

Question 18

what is the level that links all organisms together?

Answer 18

detritivores / decomposers

Question 19

what are detritivores?

Answer 19

they are consumers that derive their energy from detritus, non-living organic matter (used to be alive and then died)

Question 20

what are some important detritivores?

Answer 20

prokaryotes and fungi

Question 21

who feeds on detritrivores?

Answer 21

every one

Question 22

what do detritivores do to energy?

Answer 22

pass on energy to other microorganisms and release some of it as heat

Question 23

what is primary production?

Answer 23

the amount of light converted to chemical energy by autotrophs during a given period of time

Question 24

what is primary production measured in?

Answer 24

g/ m^2

Question 25

how do they measured primary production?

Answer 25

take the dry mass of all the plants.

Question 26

why is the dry mass of plants taken?

Answer 26

because some plants hold more water than others

Question 27

does every ecosystem have the same amount of primary production?

Answer 27

no

Question 28

what can vary the level of primary production?

Answer 28

1) levels of plants ( a lot of plant life is limited by amount of water) 2) slopes 3) terrains 4) sunlight exposure 5) angle of sunlight (steeper = less sunlight absorbed; perpendicular = more sunlight absorbed)

Question 29

what sets an ecosystems budget?

Answer 29

the extent of photosynthetic production sets the spending limit

Question 30

what determines how much energy is available for all the levels above the base?

Answer 30

how much energy is on the bottom level

Question 31

what are the most productive ecosystems?

Answer 31

tropical rain forests, estuaries, and coral reefs

Question 32

are marine ecosystems productive or unproductive? explain.

Answer 32

they are relatively unproductive per unit area, but contribute much to global net primary production because of their volume

Question 33

what controls primary production in marine ecosystems?

Answer 33

light and nutrients

Question 34

how does light control primary production in marine ecosystems?

Answer 34

the depth of light penetration affects primary production in the photic zone of an ocean or lake. only about half the solar radiation is absorbed in the first 15 m of the water. and only 5-10% reaches a depth of 75 m

Question 35

what is a limiting nutrient?

Answer 35

a limiting nutrient is the element that must be added for production in an area

Question 36

what nutrients limit primary production in marine ecosystems?

Answer 36

nitrogen and phosphorus

Question 37

what is eutrophication?

Answer 37

no more O2 in the water; kills all living organisms in the water

Question 38

what controls primary production in terrestrial ecosystems?

Answer 38

temperature and moisture

Question 39

what happens to primary production with moisture?

Answer 39

it increases

Question 40

what are some adaptations plants have to access limiting nutrients from soil?

Answer 40

1) some plants form mutualism with nitrogen fixing bacteria 2) many plants form mutualisms with mycorrhizal fungi; these fungi supply plants with phosphorus and other limiting elements 3) roots have root hairs that increase surface area 4) many plants release enzymes that increase the availability of limiting nutrients

Question 41

what is secondary production?

Answer 41

secondary production of an ecosystem is the amount of chemical energy in food converted to new biomass during a given period of time

Question 42

how much energy is available for the second level?

Answer 42

a certain amount of energy from the first level is transferred to the second level

Question 43

how do you find the biomass of the secondary level?

Answer 43

dry mass of animals

Question 44

is the level of efficiency for every pyramid the same?

Answer 44

no

Question 45

what efficiency rate do birds and mammals have? why?

Answer 45

1-3% because we eat a lot of stuff so our bodies can be less efficient, so we can release heat, so the reaction taking place in our bodies happen faster.

Question 46

what efficiency rate do insects and microorganisms have? why?

Answer 46

40+% because they don't have to use as much energy to keep their bodies warm

Question 47

what is trophic efficiency?

Answer 47

the % of production transferred from one trophic level to the next

Question 48

what is the average trophic efficiency?

Answer 48

10%

Question 49

what do trophic efficiencies allow us to see?

Answer 49

how energy is lost when we go up the food chain

Question 50

what do trophic efficiencies take into account?

Answer 50

energy lost through respiration and contained in feces, as well as the energy stored in unconsumed portions of the food source

Question 51

what is the amount of chemical energy that reaches the tertiary consumer?

Answer 51

0.1%

Question 52

what does a pyramid of net production represent?

Answer 52

the loss of energy with each transfer in a food chain

Question 53

why does nothing eat the the tertiary consumer?

Answer 53

because it is very inefficient

Question 54

what does each tier in a biomass pyramid represent?

Answer 54

the standing crops (the total dry mass of all organisms) in one trophic level

Question 55

is eating meat an efficient or inefficient way of getting energy?

Answer 55

inefficient

Question 56

why do rates at which nutrients cycle in different ecosystems vary?

Answer 56

because of differing rates of decomposition

Question 57

what is the rate of decomposition controlled by?

Answer 57

mostly temperature, also moisture and nutrient availability

Question 58

what does rapid decomposition result in?

Answer 58

relatively low levels of nutrients in the soil

Question 59

what type of ecosystems store large amounts of undecomposed organic matter?

Answer 59

cold and wet because decomposition rates are low

Question 60

is decomposition fast or slow in anaerobic muds?

Answer 60

slow

Question 61

what are biogeochemical cycles?

Answer 61

nutrient cycles in ecosystems involve biotic and abiotic components

Question 62

why is carbon important?

Answer 62

forms the framework of the organic molecules essential to all organisms. used in macromolecules

Question 63

what is nitrogen important?

Answer 63

a part of amino acids, proteins, and nucleic acids. often a limiting plant nutrient

Question 64

why is oxygen important?

Answer 64

photosynthesis and respiration; carbohydrates

Question 65

why is sulphur important?

Answer 65

amino acids, make up side chains (disulphide bridge)

Question 66

why is phosphorus important?

Answer 66

ATP, DNA

Question 67

what is restoration ecology?

Answer 67

seeks to initiate or speed up the recovery of degraded ecosystems

Question 68

what are the two strategies of restoration ecology?

Answer 68

bioremediation and augmentation of ecosystem processes

Question 69

what is bioremediation?

Answer 69

the use of organisms to detoxify ecosystems.

Question 70

what organisms are most used in bioremediation?

Answer 70

prokaryotes, fungi, or plants

Question 71

where do we mostly do bioremediation?

Answer 71

places where there was a disaster recently. ex. large oil spill or factories

Question 72

what is biological augmentation?

Answer 72

uses organisms to add essential materials to a degraded ecosystem