5.3 Energy and Ecosystems Flashcards

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1
Q

How does energy enter an ecosystem?

A

via light energy from the sun

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2
Q

What are the 2 uses of glucose in an ecosystem?

A

storage as starch
convert into any carbon containing compound

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3
Q

How is energy tranferred to the next trophic level?

A

by chemical energy transferred in biomass

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4
Q

How is energy lost from a system?

A

heat energy via resp
chemical energy lost to dead organic matter

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5
Q

What are the insoluble parts of an organism?

A

bones, fur, teeth, hair, feathers

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6
Q

What is the effect of cellulose being indigestable?

A

primary consumers that eat plants can’t digest the cellulose, so it contributes as faeces in dead organic matter

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7
Q

Why do birds/invertebrates pass on more energy than mammels?

A

invertebrates and birds are not endotherms so they have a lower rate of resp

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8
Q

Why are herbivores more efficient at energy conversion?

A

it takes up more energy from the sun to produce meat for a carnivore than to produce plants for a herbivore

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9
Q

What is the max no. of trophic levels in a food chain?

A

4

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10
Q

What is photosynthetic efficiency?

A

a measure of how well a plant is able to harvest the light energy and convert it into chemical energy

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11
Q

What are all the ways light is not absorbed into a plant?

A

absorbed by water
transmitted
reflected
light is the wrong wavelength (green light)
low CO2 conc for photosyn

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12
Q

Why is light absorbed by water on a leaf?

A

water has a high latent heat of vapourisation for evapouration

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13
Q

Why is some light reflected off a leaf?

A

thw waxy cuticle

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14
Q

What is GPP?

A

the total quantity of the chemical energy store in plant biomass in a given area/volume in a given time

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15
Q

What is NPP?

A

the chemical energy store that is left once resp losses have been accounted for

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16
Q

What is the NPP and GPP equation?

A

NPP = GPP - R

17
Q

What is the net production of consumers (N) equation?

A

N = I - (F + R)

I = chemical energy store of indigested food
F = energy lost in faeces and urine
R = energy lost in resp

18
Q

What are 2 ways biomass can be measured?

A

mass of carbon
or dry mass of tissue in an area

19
Q

How is primary and secondary productivity measured?

A

the biomass in a given area at a given time

20
Q

What happens to most of the sugars synthesised by plants?

A

used as resp substrate

21
Q

What is biomass?

A

the total mass of organic material, measured in a specific area over a set time period

22
Q

What units are used to measure biomass?

A

g/ m2

23
Q

What is a method for finding the dry mass of a plant?

A

heat and weight until a constant mass

24
Q

Why might it be useful to measure the dry mass of a sample rather than the fresh mass?

A

fresh mass can fluctuate due to water content fluctuating

25
Q

What is the equation for calculating the % efficiency of enegy transfer?

A

amount of biomass transferred / amound of biomass available
x 100
= % efficiency of energy transfer

26
Q

What is primary producivity?

A

the rate at which plants or primary producers create new organic matter through photosynthesis

27
Q

What is secondary productivity?

A

the rate which consumers (animals) convert chemical energy in their food into their own biomass

28
Q

Explain why an increase in shoot biomass can be taken as a measurement of net primary productivity

A

Represents dry mass / mass of carbon

Represents gross production minus respiratory losses