Topic 29

Question 1

Ecosystems are considered to be..

Answer 1

open systems (closed systems have no inputs and outputs)

Question 2

Inputs

Answer 2

exchanges from surrounding environment into the ecosystem

Question 3

Outputs

Answer 3

exchanges from inside the ecosystem out to the surrounding environment

Question 4

Nutrients

Answer 4

typically recycled within the system

Question 5

Inputs and outputs of nutrients exist but they are..

Answer 5

predominantly cycles within an ecosystem

Question 6

Energy come from

Answer 6

the sun (input) and leaves the ecosystem as heat (output)

Question 7

Energy is an ecosystem exists in two forms

Answer 7

• potential energy (stored)

- kinetic energy (expended)

Question 8

Sunlight is the ..

Answer 8

ultimate source of energy powering the biosphere

Question 9

All ecological process involve

Answer 9

transfer of energy

Question 10

All energy transfers are ..

Answer 10

subject to laws of thermodynamics

Question 11

Energy is not..

Answer 11

created or destroyEd. can change form or move.

Question 12

With every transfer some useful energy is..

Answer 12

lost

Question 13

1st law of thermodynamics

Answer 13

amount of energy is constant. energy cannot be created or destroyed.

Question 14

Example of 1st law

Answer 14

burning wood: potential energy (stored in molecular bond) to kinetic energy (released as heat)

Question 15

2nd law of thermodynamics

Answer 15

whenever energy is transformed, some energy become unavailable to further use.

Question 16

Example of 2nd law

Answer 16

burning fuel: kinetic energy dissipates as heat

Question 17

1st law and ecology

Answer 17

energy cannot be created or destroyed in ecosystem (constant) energy from sun is harvested by 1st producers and use to form chemical bonds in carbon based compounds. potential energy stored in these chemical bonds is transferred to consumer when they eat plants

Question 18

2nd law and ecology

Answer 18

energy becomes unavailable when transferred amount trophic levels through reeding relationships ..

Question 19

As energy is transferred form ne organisms to another a portion is ..

Answer 19

used (stored as energy in living tissues as organisms grows) but a large part dissipates as heat

Question 20

In closed systems over time the amount of energy in..

Answer 20

unusable forms increases unit no usable energy is available

Question 21

But ecosystems are open systems and ..

Answer 21

receive constant energy input from the sun and counteracts the issue

Question 22

Primary production

Answer 22

refers to the rate at which plant tissues (organic matter) is created during photosynthesis

Question 23

Plant species vary in their rates of photosynthesis or ..

Answer 23

efficiency to transform energy from sun to plant tissue

Question 24

Photosynthetic rates will be influence by..

Answer 24

• Quantity of above(shoots & leaves) and below ground (roots) tissue
• Leaf morphology (e.g. surface area)
• Modified photosynthetic pathways to increase water-use efficiency (e.g. C4 & CAM plants)
• Adaptations to low light (shade-tolerant) or high light (shade-intolerant)

Question 25

Secondary production

Answer 25

refers to the effieceny of consumers to transform energy consumed to growth and offspring

Question 26

The total energy consumed/ingested in the form of plant material flows through each individual consumer ..

Answer 26

- a portion is assimilated though the gut wall - remainder is expelled from the body as waste * *finish notes on secondary here

Question 27

Production efficiency

Answer 27

the efficiency of consumer species to transform energy consumed into 2nd production = P/A (production/assimilation)

Question 28

General patterns for P/A

Answer 28

invertebrates >> vertebrates

Question 29

Vertebrates

Answer 29

- ectotherm .>> endotherm. higher energy allocation to maintain constant body temp - carnivores >> herbivores. harder to assimilate plant tissue

Question 30

P/A of all species at each trophic level will.

Answer 30

determine energy available for next higher trophic level

Question 31

General pattern of trophic efficiency

Answer 31

quantity of energy available for use by a trophic level decrease with each successive trophic level in the food chain due to production efficiencies (2nd law)

Question 32

Ecological rule

Answer 32

only 10% of the energy stores as biomass within given trophic level is converted to biomass as next higher trophic level (10% rule)

Question 33

Result of ecological rule

Answer 33

decrease in the biomass of organisms within each successive trophic level (pyramid of biomass)

Question 34

Primary productivity relies on

Answer 34

photosynthetic organisms taking up carbon and other minerals

Question 35

Living tissue can be consumed..

Answer 35

passing minerals, carbon and energy up the food chain. age die and decompose returning minerals tot he soil

Question 36

Some carbon is added to..

Answer 36

soil but most is release back tiny atmosphere

Question 37

Decomposers

Answer 37

recycle minerals back into their local ecosystems. essential function in all ecosystems

Question 38

Nutrient (calcium, nitrogen) source is

Answer 38

atmosphere or weathering of rocks and minerals

Question 39

Taken up by plants

Answer 39

move through food chain via feeding relationships

Question 40

Significant portion of nutrient in an ecosystem are..

Answer 40

stored in organic form within living tissue of plants and animals

Question 41

Most of essential nutrients are recycled within ecosystem by ..

Answer 41

decomposers = internal cycling

Question 42

Once living tissue dies, it falls into the soil or aquatic sediments in the form of..

Answer 42

dead organic mayor

Question 43

Decomposers breakdown the chemical bonds from during construction of plant and animal tissue and releases..

Answer 43

energy originally fixed by photosynthesis, converts organic compounds into inorganic compounds (mineralization) for use by plants

Question 44

Succession of species occurs until..

Answer 44

material is finally reduced completely to inorganic nutrients

Question 45

All organic matter does not..

Answer 45

decompose at the same rate

Question 46

Simple compounds result in

Answer 46

higher net energy gain. (=energy game - loss) to decomposers relative to complex compounds

Question 47

Simple carbohydrates are..

Answer 47

high quality- breaking chemical bonds yields much more energy than required to synthesize the enzyme to break them down

Question 48

Microbial decomposers (bacteria and fungi)

Answer 48

secrete enzymes into plant and animal tissues to breakdown the complex organic compounds. some products absorbed as food

Question 49

Detritivores

Answer 49

animals that feed on dead organic material and waste products (invertebrates) aid decomposition by fragmenting larger pieces

Question 50

More complex structure carbon based compounds..

Answer 50

(cellulose) are low quality and most costly to decompose

Question 51

Even more complex (lignins) are..

Answer 51

lower quality and weald no net energy gain

Question 52

Abiotic factors have direct influence on decomposition rates..

Answer 52

temp and moisture greatly influence microbial activity

Question 53

Cool, dry conditions reduce..

Answer 53

inhibit activity

Question 54

Warm moist conditions are optimal

Answer 54

conditions for activity

Question 55

Rates of internal cycling of nutrients depend directly on

Answer 55

rates of 2 processes: primary production and decomposition

Question 56

Primary production determines the rate of..

Answer 56

nutrient transfer from inorganic to organic form (nutrient uptake)

Question 57

Decomposition determines the rate of..

Answer 57

transformation of organic to inorganic form (mineralization)

Question 58

Reduced availability of inorganic nutrients in the soil will diretly

Answer 58

reduce photosynthesic rates and primary production

Question 59

Influences the input of dead organisms matter to the..

Answer 59

detrital food chain by reducing the total quantity of dead organic matter produced (feedback mechanisms in internal cycling of nutrients within an ecosystem)