3.5.3.1 - Energy and Ecosystems (GPP and NPP) Flashcards Preview

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Flashcards in 3.5.3.1 - Energy and Ecosystems (GPP and NPP) Deck (17)
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1

Define ecosystem

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

2

What are producers?

Organisms that make their own food - usually by photosynthesis.

3

What is biomass?

The chemical energy stored in the plant

4

Define dry mass

The mass of the organism with the water removed

5

What unit are typically used to measure biomass?

dry mass of tissue per unit area per time.

6

How do you measure dry mass?

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

7

How can you estimate the chemical energy stored in biomass?

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

8

What is the unit of energy?

Joules or kilojoules

9

What does GPP stand for?

Gross primary production

10

Define GPP

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

11

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

approximately 50%

12

Define respiratory loss?

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

13

How can you calculate NPP?

NPP = GPP - R

14

What does NPP stand for?

Net primary production

15

Define net primary production

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

16

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

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

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

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