3.5.3.1 - Energy and Ecosystems (GPP and NPP) Flashcards

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1
Q

Define ecosystem

A

All the organisms living in a particular area and all the abiotic conditions.

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2
Q

What are producers?

A

Organisms that make their own food - usually by photosynthesis.

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3
Q

What is biomass?

A

The chemical energy stored in the plant

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4
Q

Define dry mass

A

The mass of the organism with the water removed

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5
Q

What unit are typically used to measure biomass?

A

dry mass of tissue per unit area per time.

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6
Q

How do you measure dry mass?

A

The sample is dried in a over (low temperature). The sample is then reweighed at intervals until a constant mass is reached.

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7
Q

How can you estimate the chemical energy stored in biomass?

A

Burn it in a calorimeter. The amount of heat given off tells you how much energy is in it.

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8
Q

What is the unit of energy?

A

Joules or kilojoules

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9
Q

What does GPP stand for?

A

Gross primary production

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10
Q

Define GPP

A

The total amount of chemical energy converted from light energy by plants, in a given area, in a given time.

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11
Q

How much GPP is lost to the environment as heat when the plants respire?

A

approximately 50%

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12
Q

Define respiratory loss?

A

The amount of GPP that is lost to the environment as heat when the plants respire.

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13
Q

How can you calculate NPP?

A

NPP = GPP - R

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14
Q

What does NPP stand for?

A

Net primary production

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15
Q

Define net primary production

A

The energy available to the plant for growth and reproduction. The energy is stored in the plants biomass.

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16
Q

Why does only 90% of the chemical stored in the consumers food transferred to the next trophic level?

A

Not all the food is eaten.
Some parts are indigestible.
Some is egested as faeces.
Some is lost through respiration or excretion of urine.

17
Q

How can Net production of consumers (N)be calculated?

A
N = I - (F+R)
N Net production 
I Chemical energy in ingested food
F Chemical energy lost in faeces and urine
R Energy lost through respiration