3.5.3 Energy and Ecosystems

Question 1

What is energy transfer along
food chain not 100% efficient?
(9)

Answer 1

1. Some light energy fails to strike/is reflected/not of appropriate wavelength;
2. Efficiency of photosynthesis in plants is low
3. Respiratory loss / excretion / faeces / not eaten;
4. Loss as heat;
5. In excreta / excretion / urine / carbon dioxide;
6. Inedible parts / indigestible parts / egestion / to decomposers
7. Efficiency of transfer to consumers greater than transfer to producers;
8. Efficiency lower in older animals/herbivores/ primary consumers/warm blooded animals/homoiotherms;
9. Carnivores use more of their food than herbivores

Question 2

How do we improve
productivity during farming of
animals? (5)

Answer 2

1. Slaughtered while young so more energy transferred to biomass;
2. Fed on controlled diet so higher proportion of food absorbed/lower proportion lost in faeces;
3. Movement restricted so less respiratory loss;
4. Heating/Kept inside so less heat/respiratory loss;
5. Genetically selected / selective breeding (for high productivity)