1. Controlling the temperature of the body

2.  Endotherms  Ectotherms
 Generate heat through  Absorb heat from the
metabolic activity surroundings
 Eg. humans, birds  Use behaviours to maintain a
constant body temp
 Eg fish, reptiles
Both the gecko and the scorpion are at the same
temperature as the air surrounding them. Notice the
difference between these cold-blooded creatures and the
warm-blooded humans holding them.

3.  Endotherms and Ectotherms can be further classified
into two groups:
Homeotherms Poikilotherms
Animals that can maintain a Animals that cannot control their body
relatively constant body temp temp. Body temp changes with the
Eg. mammals, some insects, temp of the surroundings. Eg fish and
birds reptiles
Mammals can use up
to 80% of the energy
obtained from food
simply to maintain In the image to the left, the lizard is just above room temperature,
body temperature. being warmed by the human hand holding it. To warm up lizards will
seek a sunny area and bask in warm sunlight, as in the image to the
right.

4.  Any organism
that is hotter
than its
surrounding
may lose heat
 Heat can be
lost through:
 Radiation
 Conduction
 Convection
 Evaporation

6.  Conduction – transfer of heat from a hotter to
cooler object which is it in contact with
 Convection – transfer of heat by warm air or water
rising and being replaced by cool air or water
 Evaporation – as water vaporises it takes heat with
it form the body –cooling effect
 Radiation – transfer of heat by means of infra-red
waves

7. • An example of
how the human
body regulates
body
temperature.

8.  Adaptations allow an organism to survive in a
range of environmental conditions that exist in
their habitat.
 Structural – body shape
 Behavioural – what the animals does
 Physiological – Internal metabolic functions
 There are a number of adaptations animals have
to be able to successfully regulate their
temperature

9. Increase Body Temperature Decrease Body Temperature
Vasoconstriction: Arterioles get smaller to reduce Vasodilation: arterioles dilate (widen) so more
blood going to skin, keeping the core warm. blood enters the skin capillaries and heat is lost.
Shivering: Rapid contraction and relaxing of Sweating: Glands secrete sweat which removes
skeletal muscles. Heat produced by respiration. heat when water evaporates.
Piloerection: Hairs on skin stand up (trapping more Pilorelaxation: Hairs on skin flatten (trapping less
air) and decreasing heat loss. air) and increasing heat loss.
Curling up: reduces heat loss, decreases surface Stretching Out: By opening up, the body has a
area. larger surface area.
Huddling together: animals group together and Burrowing : To avoid heat of day
share body heat., thus reducing heat loss.
Hibernation: When an animal cannot cope with
conditions animals undergoes dormancy
Basking: take in heat from surroundings
Fat: insulates against heat loss.
Fur: Traps warm air to maintain heat
Some arctic animals can also have antifreeze substances in their blood
to prevent cell damage due to extreme cold!

10. Maintaining a Water Balance

11.  All animals have some mechanism to regulate water balance.
 They balance water uptake vs. water loss and regulate solute
concentration within cells and tissues
 The fluid in cells, blood and tissue fluids contains a variety of
solutes dissolved in water. This fluid is the medium in which
everything happens – chemical reactions, transport of nutrients,
gases and wastes.
 Water is lost continually from the body in urine and faeces,
through our sweat glands and tear ducts.
 Osmoreceptors in the hypothalamus detect changes in the
water concentration in the blood and body tissues

12. Water Balance in Two Different Land Mammals
Water balance in Water balance in
a kangaroo rat a human
(2 mL/day) (2,500 mL/day)
Ingested Ingested
in food (0.2) in food (750)
Ingested
in liquid
Water (1,500)
gain
(mL)
Derived from Derived from
metabolism (1.8) metabolism (250)
Feces (0.09) Feces (100)
Water Urine Urine
loss (0.45) (1,500)
(mL)
Evaporation (1.46) Evaporation (900)

13.  Living things have evolved diverse ways of
regulating their water balance.
 In vertebrates including frogs, lizards and
humans, the kidneys are the main organs of
excretion.
How the Kidney functions when water levels are low:
If blood concentration increases:
1. Nerve impulses sent from the hypothalamus stimulates
the pituitary gland
2. Pituitary gland secretes ADH (Anti-diuretic hormone)
3. ADH causes the kidneys to reabsorb more water
4. More concentrated Urine is produced

14. Osmoregulation and the kidneys (Simple)
Water content of Water content of
the blood LOW the blood HIGH
Too much water drunk
Too much salt
or sweating
Brain
Brain
produces Water content
produces
More ADH of the blood normal
Less ADH
High volume of water Low volume of water
reabsorbed by kidney reabsorbed by kidney
Urine output
Urine output HIGH
LOW
(large volume of
(small volume of dilute urine)
Concentrated urine)
Please Note: Urination still ends up with a net loss of water so it still needs to acquired.

15. Structural and Physiological Behavioural Adaptation
Adaptations
• Waterproof or impermeable layer can • Burrowing underground for weeks at a time
reduce water loss (e.g.. Scales, hair,
feathers, exoskeleton). •Earthworms curl up in a ball of mucous
• Insects reabsorb water from the rectum, •Some arthropods position their bodies to
excreting a dry faeces collect condensation at night.
•Birds and reptiles reabsorb water from •The desert hopping mouse wraps its fluffy tail
their cloaca (the cavity into which their around its mouth to trap water vapour.
rectum and ureter open). They excrete
uric acid instead of urine. •Nocturnal life styles in dessert biomes.
•Frogs swell up like a ball retains urine in
its bladder for the dry season

16.  Camels metabolise the fat in
their hump, which gradually
shrinks as the fat is used up.
 As the fat is used up water is
produced
 1g of fat produces twice as much
water than the equivalent mass
of carbohydrates.
 However the camel can’t
produce enough water this way.
 As water is lost, the body fluids
become more concentrated but Once water is available, camels rehydrate
the camel’s tissues are extremely by consuming large volumes of water, up
tolerant of this condition. to 40 L, in a matter of minutes.

17.  The Desert frog tucks itself in a
water-conserving position under
the ground.
 It then encases itself in a cocoon
of layer upon layer of shed skin.
 The cocoon completely
surrounds the frog except for its
nostrils, and the little space
Cyclorana platycephalus, breaking from between the body and the
its cocoon after rain. cocoon becomes humid.
 The frog’s metabolic rate slows
as it enters aestivation, the
summer equivalent of winter
hibernation.

18. Water Balance in both fresh and saltwater fish

19.  Water balance is just as difficult in aquatic
organisms
 Some marine invertebrates have water
concentration in their cells the same as the
surrounding water concentration (isotonic).
 These organisms are called osmoconformers.
Jellyfish Crabs Sea Anemones

20.  Marine vertebrates like fish have body fluids that tend
to be hypotonic to their surroundings.
 This means that their body fluids are of a lower
concentration compared with the water in which they
live.
 In saltwater fish:
 water is lost to the surface by the gills
 to replace water they take in large amounts of surrounding water BUT
this is high in salts.
 Organisms that have specialised mechanisms for
dealing with water balance are called
osmoregulators.

22.  Freshwater animals tend to have
concentration of ions in their tissues higher
than the surrounding water, water molecules
therefore tend to enter their cells.
 To Also deal with
 have high kidney filtration rate
 produce large amounts of dilute urine
 scales to reduce soft tissues to water