Maintaining a Balance

Biology – Stage 6

© Taronga Zoo Education Centre. These sheets may be reproduced for teaching purposes. Permission to reproduce

them for other purposes may be obtained from Taronga Zoo Education Centre.

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This resource is to be used as part of an excursion to Taronga Zoo. The resource

and related workshop is linked to the NSW School Curriculum and has been

developed in consultation with Department of Education and Training Curriculum

Coordinators and NSW School Teachers. It is a comprehensive kit of information

and activities designed to ensure maximum benefit to you during your excursion to

Taronga Zoo.

Contents

Introduction 2

NSW School Curriculum Links 3

Prior Knowledge and Experience 4

At the Zoo 4

Student field notes 5-16

Maintaining a Balance

Zoo

Education

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NSW School Curriculum Links

Stage 6 Biology

9.2 Maintaining a Balance

Taronga Zoo exhibits a range of animals which will enable students to develop an

excellent understanding of the adaptations animals have to maintain a balance

within the narrow limits for survival.

The activities detailed in this resource address the following syllabus related topics:

• Compare responses of named Australian ectothermic and endothermic

organisms to changes in the ambient temperature and explain how these

responses assist temperature regulation.

• Analyse information from secondary sources to describe adaptations and

responses that have occurred in Australian organisms to assist temperature

regulation.

• Analyse information from secondary sources to compare and explain the

differences in urine concentration of terrestrial animals, marine fish and

freshwater fish.

• Use available evidence to explain the relationship between the conservation of

water and the production and excretion of concentrated nitrogenous wastes in

a range of Australian insects and terrestrial mammals.

The ‘Maintaining a Balance’ excursion to Taronga Zoo also provides students

opportunities to further develop skills in communicating information and

understanding, scientific thinking, problem solving and working individually and in

teams.

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Prior Knowledge and Understanding

It would be most beneficial if students had the following prior knowledge and

understanding before their visit to the Zoo.

- the maintenance of a constant internal environment is important for optimal

metabolic efficiency

- homeostasis

- endothermic and ectothermic

- the process of diffusion and osmosis

- passive and active transport

- the role of the kidney

- the processes of filtration and reabsorption in the mammalian nephron

At the Zoo

Workshop with Zoo Educator

Workshops are approximately 50 minutes duration and include content on how

many Australian native animals maintain homeostasis this is supported and

enhanced with native animal encounters.

Seal Presentation

Seals are exceptional thermoregulators, needing to cope with temperature extremes both in water and on land. Visit the seal show to provide students with an

excellent opportunity to extract information about seal thermoregulation from expert

marine mammal keepers.

Excursion Fieldwork

Copy the following worksheets for your students to complete in their free time at

the Zoo. The questioning is designed to have students apply their knowledge of

thermoregulation and water balance from a captive husbandry point of view.

Students will also be challenged on their ethical attitudes towards keeping animals

in captivity.

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Koala

Provide possible explanations for the koala facts given below in relation to

thermoregulation and/or water balance.

Describe features of the exhibit that assist in the thermoregulation of the koala.

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Suggest what Zookeepers could do to avoid heat stress in koalas on a 40Cº day.

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Activity – nocturnal, sleeps 18hrs per day ……………………………………………………

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No sweat glands, do not pant ……………………………………

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Posture – temperature dependant ………………………………………

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Koala is an Aboriginal word meaning ‘no drink’

Brain size – 0.2% of body weight

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Faeces – dry pellets Urine – highly concentrated urea ……………………………………………

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Back fur – very high insulation Chest fur- low insulation

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Core temperature - 35-36Cº

Water intake – 400ml per day

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Corroboree Frog

The Corroboree Frog exhibit is kept at a temperature of 5Cº. These tiny frogs can

survive comfortably in temperatures ranging from 0Cº to 30Cº. Suggest a reason

for the deliberate lowering of the temperature of the frogs’ surroundings.

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Fertilised eggs rapidly enlarge as they fill

with water ……………………………………................

……………………………………................ Lays eggs in sphagnum moss ……………………………………………

………………………………………....... Changes posture when basking ……………………………………

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Uric acid is stored when the frog is out

of water …………………………………………..

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Tadpoles hatch in winter, already with

hind legs and without gills

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Tadpole growth-rate slows over

winter months

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Black-headed Python

Many snakes are ambush predators, spending up to 3 weeks lying motionless to

fool potential prey into approaching. Give an explanation as to how a snake can

do this yet also thermo-regulate so that their body temp is high enough to digest

prey.

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Some Australian snakes give birth to live young (the eggs hatch before they young

emerge). Hypothesize why this may be an adaptation to cope with cold

temperatures.

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Found in arid conditions

Feeding – greatly reduced in cooler months

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Incubation - coil around eggs and ‘shiver’

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Behaviour - nocturnal in warm weather, diurnal in cold

weather …………………………………………

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Skin is impermeable …………………………………......

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Head section is black

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Basking behaviour

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Lacks sensory heat pits for detecting endothermic prey

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Asian Elephant

An elephant weighing 2000000g has a skin surface of roughly 100000 cm². A

rat weighing 300g has a body surface of 300 cm².

Compare the surface area to volume ratios of these two mammals.

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Make a general statement comparing the ability of large and small animals to give up their

heat?

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Use this information to postulate what would happen if elephants did have sweat glands all

over their body rather than large ears.

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Ear flapping – blood temp drops over

8Cº as it passes through the ears

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Core temperature - 36-37Cº

Skin – 3cm thick on legs and back, paper thin on chest and abdomen

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250 daily litres of water consumed

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Skin surface area is twice as large as

needed

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Dust bathing behaviour

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Throat pouch – contains stored water

which can be drawn out by trunk ......................................

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Sweat glands only found between toes

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Andean Condor

When an Andean Condor drops down to ground for feeding its body may experience a temperature shift from l2Cº to 40Cº. How do you think Andean Condors cope with this extreme?

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Many folds of bare skin on head

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Birds do not sweat

Body temperature drops by several degrees overnight

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Spreads wings in morning

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Fluff feathers when cold, smooth feathers when hot

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Counter current heat exchange in feet

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Defecates on legs in hot weather

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Retracts bare head into tuft of neck feathers when

flying at high altitudes

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A long way from home

Locate a Zoo animal that is originally from a location/climate markedly different to the climate

and conditions found in Sydney.

1. Draw the animal in its

exhibit.

2. Label the animal with

possible responses the animal may have had in order to cope with its new

environment.

3. Label the features of the

exhibit that have attempted to

assist the animal’s ability to

cope in its new environment.

Do you feel the animal is suitable for Sydney’s Taronga Zoo? Explain.

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Find out why the animal is part of the Zoo collection.

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Seal Presentation Notes

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Short-beaked Echidna

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Red Kangaroo

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Green Tree Frog

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Shingleback Lizard

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Saltwater Crocodile