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Food webs, Classification and Biodiversity Additional secondary activities to accompany the Gould League Food webs, Classification and Biodiversity kit. |
Populations
Level: 6 and 7
Curriculum Area - Science, Mathematics
Outcomes
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Students:
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Materials and preparation
The following information as an overhead or handout sheet for the students, African cut-outs for developing food webs.
Method
The students work through the following information to calculate the area of grassland that is required to support a pride of lions.
Chief Zoogootie's Wildlife Park
Chief Zoogootie has been given a large donation by a corporate sponsor to set up a wildlife park. The Chief's totem is the lion and so he is very keen to have a pride of lions in the park. The Chief has employed you as a food web consultant to check the area the park should cover to sustain a pride of ten lions. In calculating the park area you use the following information:
The Chief will only allow zebra and wildebeest to be present in the park as food for the lions.
Lions feed twice every 7 days. The lion pride is to be made up of 2 males and 8 females.
There are to be no other large predators in the park.
The grass that the zebras and wildebeest feed from is also eaten by a number of other animals such as termites and crickets, so each animal group only gets 5% of the available grass.
Male lions weigh an average of 230kg and require a minimum of 20kg of meat a week to survive, while the lighter females (average weight of 150kg) require a minimum of 15kg of meat a week.
Zebras and wildebeest each produce 1 foal per year but half invariably die of natural causes.
As a guide to grass production you find out from an Australian farmer that 50 lots of 30kg bales of hay are obtained from a hectare.
The amount of food or biomass available to be passed up a food chain is reduced by a factor of 10 as each animal in a food chain uses up 10% of the food value in body functioning and heat.
Zebras in captivity are feed the equivalent of 2 bales of hay/week/animal.
Wildebeest in captivity are fed 1 bale of hay/week/animal.
The sex ratio in both zebra and wildebeest herds is always approximately 1:1.
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