The diagram below illustrates part of the carbon cycle.
Which process is shown by the arrow labelled Y?
Photosynthesis
Feeding
Respiration
Combustion
Did this page help you?
The diagram below illustrates part of the carbon cycle.
Which process is shown by the arrow labelled Y?
Photosynthesis
Feeding
Respiration
Combustion
Did this page help you?
The image shows a food web.
Which organism, from the food web, feeds on the greatest variety of organisms?
Whelks
Crabs
Limpets
Mussels
Did this page help you?
Which letter shows the path of the energy from the sun?
chemical energy in sugars → stored in plants → trapped in chlorophyll
trapped in chlorophyll → chemical energy in sugars → stored in plants
stored in plants → chemical energy in sugars → trapped in chlorophyll
stored in plants → trapped in chlorophyll → chemical energy in sugars
Did this page help you?
The graphs below show how the number of carnivores change over a period of time in a habitat.
At point X the herbivores in the habitat are removed.
Which graph correctly shows the effect of this on the number of carnivores?
Did this page help you?
Extended Tier Only
Which statement gives the best explanation for why most food chains have no more than five trophic levels?
Because 20% of the energy is transferred at each level and after 5 levels, all the energy is used up (5 × 20% = 100%).
The numbers of organisms are insufficient because the top predator has to have a count of 1 in a pyramid of numbers.
The biomass transferred from a consumer to the next-level consumer is too little.
There is a large amount of energy loss at each level so insufficient energy can be passed up to the sixth trophic level.
Did this page help you?
Look at the information about a food chain.
Organism | Number | Biomass / kg |
Oak tree | 1 | 400,000 |
Aphids | 9,000 | 900 |
Predatory midges | 120 | 45 |
What is the percentage biomass of the aphids transferred to the midges?
0.05 %
1.3 %
5%
0.225 %
Did this page help you?