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Food Webs Energy Transfer

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Food Webs Energy Transfer

Follow the arrows from the food to the organism that eats it: arrows show the direction of energy transfer. Use the food-web information and energy model to answer the questions. Energy values are simplified estimates.

Follow the energy

In a forest-edge food web, energy moves along these feeding links: - mānuka leaves → caterpillar - mānuka nectar → tūī - caterpillar → riroriro (grey warbler) - wētā → riroriro - wētā → ruru (morepork) - riroriro → ruru - fallen leaves and dead organisms → fungi and bacteria The tūī also eats fruit and nectar from other plants. Fungi and bacteria break down dead material; they are not shown as a food source for the predators in this web.

1.Which organism in the food web is a producer, and what makes it a producer?

2.Choose the correctly ordered food chain that ends with the ruru.

mānuka leaves → caterpillar → riroriro → ruru
ruru → riroriro → caterpillar → mānuka leaves
mānuka leaves → ruru → caterpillar → riroriro
caterpillar → mānuka leaves → ruru → riroriro

3.In the link wētā → ruru, what does the arrow represent?

4.Classify each organism as a producer, consumer or decomposer: mānuka, wētā, ruru, fungi.

mānuka
wētā
ruru
fungi

consumer
decomposer
consumer
producer

5.A food-web model starts with 12,000 kJ of energy stored in producer biomass. If about 10% transfers to the next trophic level, how much energy is available to primary consumers?

6.Using the same approximate 10% transfer, continue the model: from 1,200 kJ in primary consumers, how much reaches secondary consumers, and how much reaches tertiary consumers? Show your calculation.

7.True or false: The energy that is not transferred to the next trophic level has disappeared completely from the ecosystem.

TrueFalse

8.If caterpillar numbers fell sharply, predict one likely effect on riroriro and one likely effect on ruru. Explain why the effects may not be identical for both birds.

9.Explain how fungi and bacteria help keep nutrients cycling, and why energy does not transfer from them back to the mānuka.

10.A pest-control plan greatly reduces wētā. Use the food web to describe two possible consequences for other organisms. Include a reason for each.