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ADAPTATIONS
Biology ATAR Unit 2
ADAPTATIONS
Adaptation
 The inherited characteristic that makes an
organism well suited to its environment and
lifestyle.
 Adaptations enhance an organism's ability to
survive and reproduce in a particular
environment.
Different types of habitats include:
 Terrestrial
 Aquatic
 Freshwater
 Marine
TERRESTRIAL HABITATS


Terrestrial plants and
animals need water,
oxygen and some form of
protection or shelter from
environmental conditions
such as wind and
temperature.
Terrestrial organisms are
often exposed to extreme
temperature changes due
to weather conditions and
the seasons, with water
loss a constant problem for
many terrestrial organisms.
AQUATIC HABITATS
There are four abiotic
factors that affect plant and
animal life in water:
1. Oxygen is not very
soluble in water.
2. Light rarely reaches 100
metres below the
surface.
3. The temperature of water
decreases with depth.
4. The water often has
either a higher salt
concentration or a lower
salt concentration than
the organisms’ cells.
TYPES OF ADAPTATIONS
Adaptations can be
classified into
three categories:
1.
2.
3.
Structural
 Colour
 Mimicry
Behavioural
Physiological.
STRUCTURAL ADAPTATIONS
Structural adaptations are the
physical features of an
organism that help it to
survive in its environment
Examples
 An insect’s mouth parts allow
it to obtain food from different
parts of a plant.
 The leaves of the mulga tree
are narrow in order to reduce
water loss through
evaporation
 The leafy sea dragon is
protected because it looks
like seaweed.
STRUCTURAL ADAPTATIONS
PROTECTIVE COLOURATION
Colouration and protective
resemblance allow an
animal to blend into its
environment.
 Their camouflage makes
it hard for enemies to
single out individuals.

STRUCTURAL ADAPTATIONS
MIMICRY
 Mimicry
allows
one animal to
look, sound, or
act like another
animal to fool
predators into
thinking it is
poisonous or
dangerous.
BEHAVIOURAL ADAPTATIONS
Behavioural adaptation is the way an organism
behaves or acts to survive in its environment
Examples
 Kangaroos rest in shade during the heat of the day.
 Kangaroos pant or lick their forearms to lose body
heat by evaporation.

BEHAVIOURAL ADAPTATIONS
 The
desert hopping
mouse is nocturnal
and stays in its
burrow during the
day to avoid
extremes of
temperature.
 Birds will migrate to
places where water
and food are more
plentiful.
PHYSIOLOGICAL ADAPTATIONS

Physiological adaptations relate to the functioning
of the body and how it reacts internally to enhance
survival in response to environmental change.
Example
 Red kangaroos living in
an environment where
drinking water is scarce
produce very
concentrated urine,
which conserves water
and enables them to
tolerate salty drinking
water.
PHYSIOLOGICAL ADAPTATIONS
Examples
 Mangroves have
physiological
adaptations to survive in
salty estuaries. Excess
salt is stored in the
leaves and removed
when the leaves fall off.
 A koala's low metabolic
rate and low energy
requirements enable it to
obtain sufficient nutrients
and water from a diet of
only gum leaves.
THE BILBY: AN AUSTRALIAN EXAMPLE
The bilby once lived across most of the Australian inland deserts.
Today its range is a lot more restricted (primarily due to the
environmental problems that humans cause). Only small,
fragmented populations survive in parts of the Tanami, the Gibson
and the Great Sandy deserts.
Like most desert animals the bilby
hides during the day and forages
at night to avoid heat and
dehydration. Bilbies dig burrows
that are one to two metres below
ground and moister and up to ten
degrees cooler than the surface.
They are so efficient in conserving water that they don't need to
drink. They get enough moisture from their food: seeds, bulbs,
fungi, spiders and insects, which they find by scratching and
digging.