Transcript Interactions_C6 -

© 2009 Marshall Cavendish International (Singapore) Private Limited
Questions to think about…
What are the
types of
adaptations?
How do adaptations
improve chances of
survival?
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Adaptations
• Living things that can survive in their natural habitats are
said to be adapted to their environment.
• Organisms that are adapted to their environment are
able to:
o
o
o
o
get air, water and food
cope with physical conditions such as temperature and light
protect themselves from their enemies
reproduce
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Adaptations
• Special characteristics that help organisms
survive in their natural habitats are called
adaptations.
Adaptations
structural
special body parts of an
organism that help it to
survive in its natural habitat,
for example, its colour,
shape and body covering
behavioural
special ways an organism
behaves to survive in its
natural habitat
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Adaptations for breathing in
water
• Aquatic animals have to breathe in oxygen
that is dissolved in the water or from the
air above the water.
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Gills
• Animals that breathe in oxygen that is
dissolved in the water usually have gills.
• When oxygen-rich water passes over the
gills, dissolved oxygen is taken in and carbon
dioxide is given out.
• Gills can be found in aquatic animals like fish,
shrimps and tadpoles, as well as in some
insects like dragonfly nymphs.
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Gill chambers
• There are animals which breathe with gills but
can also stay out of water for short periods of
time.
• These animals, such as crabs and mudskippers,
have gill chambers to store water and keep the
gills wet.
• When the animals are on land, they can use the
oxygen from the water stored in the gill
chambers.
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Skin
• Some aquatic animals use their
skin to take in oxygen that is
dissolved in water.
• The skin is usually thin and soft,
and kept wet all the time.
• Examples of these animals include
aquatic worms like tubifex worms
and flatworms, and amphibians like
frogs and toads.
• Frogs and toads can breathe
through their nostrils when on land.
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Air tube
• Many aquatic insects have to take
in oxygen from the air directly
using air tubes.
• Mosquito larvae and pupae, water
stick insects and water scorpions,
all have air tubes.
• These tubes extend from their bodies
and stick out above the water surface
to get oxygen.
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Air bubble
• Other aquatic insects like water beetles and
water spiders trap air bubbles by using their
adapted wings, legs or hairy bodies.
• In this way, they carry their own supply of air
and can spend time in the water to hunt for
food.
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Special nostrils
• Mammals cannot breathe in oxygen that is
dissolved in water, but can only breathe in
oxygen from the air through their lungs.
• Mammals that spend time underwater like seals
and dugongs have nostrils at the tip of their
snouts.
• When they want to breathe, they push their
nostrils above the water surface.
• But when they are underwater, they keep their
nostrils shut to keep water out.
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Blowhole
• Aquatic mammals like whales and dolphins have
blowholes on top of their heads.
• This enables them to breathe even when most of
the body is underwater – with only the blowhole
above the water surface.
• Whales and dolphins can also hold their breaths
for long periods of time.
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Adaptations for movement
Let usMovement
take a look
is at
important
how
for
animals
animalsadapt
so that
to moving
they can hunt for
food
in water
andand
escape
in air.
from danger.
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Moving in water
• Movement in water involves a force that
acts against the direction of this
movement.
• Aquatic animals need to overcome this
force so that they can move easily through
water.
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Streamlined body shape
• The bodies of most aquatic animals are
streamlined.
• A streamlined body shape is one that is
narrow at both ends, and broad in the
middle.
• This shape allows the animals to move
quickly through water.
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Modified limbs
• Most aquatic animals have modified
limbs to help them move in water.
Fins keep a fish balanced
have
and its Animals
powerfullike
tail seals
propels
flippers for paddling in
it forward.
water.
Frogs A
have
webbed has oar-like
backswimmer
feet forlegs
swimming.
for swimming.
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Swim bladder
• Besides being able to swim, aquatic
animals need to stay afloat in water.
• Most fishes have swim bladders.
• The swim bladder is like a little balloon of
air inside the body of the fish.
• The fish can control the depth it wants to
float at by varying the amount of air held in
its swim bladder.
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Moving in air
• Some animals such as bats, insects and birds
are able to fly in the air.
• Flying allows them to escape from danger
quickly, and swoop down on a distant prey.
• All flying animals have wings.
• Unlike insects and bats which
are small and require less
effort to fly, birds, which can be
large, have special
adaptations for flight.
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Wings
• Birds have wings that are well developed
for flying.
• Bird that have heavy bodies and less
developed wings cannot fly.
• These include the ostrich,
emu, goose, chicken and
turkey.
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Flight muscles
• Birds also have strong flight muscles for
flapping their wings.
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Feathers
• Birds are the only animals that have
feathers.
• Feathers make light but strong wings, and
also keep birds warm.
• The warmth provided by the feathers
makes sure that the flight muscles can
work properly.
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Streamlined body shape
• Just like in water, there is a force that
opposes motion in air.
• When a bird is flying, its streamlined
body shape helps it to overcome this
come.
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Hollow bones
• Bird have strong but hollow bones.
• This is important as this reduces the bird’s
body weight and makes flight easier.
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Adaptations for catching prey
All predators have adaptations that allow
them to hunt for food.
For example,
• Sharks have a strong sense of smell
and are generally able to detect as
little one part of per million of blood in
seawater. This makes it easy for
sharks to find their prey.
•
Sharp teeth is also one of the most
visible adaptations on many animals.
Sharp teeth helps an animal eat meat.
Found primarily on meat-eating
animals, or carnivores, sharp teeth
are used mainly for tearing and
chewing of an animal’s prey.
•
Other adaptations for catching prey
include strong jaws, claws, sticky
tongue, super senses and speed.
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Adaptations for obtaining
sunlight
Soland
these
plants
have
Most
plants
and
trees
PlantsOther
needplants,
to get enough
special
adaptations
for
their
have
strong,
woody
stems
sunlight
in have
order soft,
to carry
however,
leaves to get sunlight. Such
to hold
theirstems
branches
outupphotosynthesis.
non-woody
and
plants
can
be
grouped
as
andcannot
leavesgrow
to getupright.
enough
creepers
or climbers.
sunlight.
So how do
plants get
sunlight?
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How land plants get sunlight
• Creepers
Creepers grow horizontally on
the ground.
o Their shoots spread out on all
sides of the main stem.
o Carpet grass and mimosa are
examples of creepers.
o
carpet grass
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How land plants get sunlight
• Climbers
o
o
tendril of a passion fruit
vine coiling around a
branch
Climbers climb onto
supports such as
walls, fences or other
plants that have
strong stems.
Some climbers have
tendrils or clasping
roots to attach
themselves to the
supports.
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How aquatic plants get sunlight
• Sunlight cannot reach deep into water. The
deeper the water is, the less sunlight is
available.
• Thus, to get enough sunlight, many aquatic
plants adapt by floating or sticking their
leaves out of the water surface.
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How aquatic plants get sunlight
• The water lily and lotus
have large waxy
leaves.
• This prevents water
from collecting on the
leaves.
• When leaves collect
water, they will sink
beneath the water
surface.
waxy leaf
lotus
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How aquatic plants get sunlight
• Aquatic plants also have air spaces in their leaves and
stems.
• These air spaces keep the plant upright in the water to
get more sunlight.
• The leaves of the water spangle and water moss fern
have hairs that trap air.
swollen leaf stalk in the
water hyacinth contains air
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Adaptations for coping with
extreme temperatures
• Living in a cold environment
white coat
the North do
andthe
What In
adaptations
Poles, itliving
is
plantsSouth
and animals
cold
all year
round.
here
need
to survive?
thick fur and
an extra
layer of fat
soles
covered with
stiff hairs
polar bear
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Adaptations for coping with
extreme temperatures
• Living in a cold environment
closely-packed
feathers
penguin
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Adaptations for coping with
extreme temperatures
• Living in a cold environment
a thick layer of fat
called blubber
walrus
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Adaptations for coping with
extreme temperatures
• Living in a cold environment
Some plants in cold places, such as lichens
and some grasses, grow in clumps close to
the ground.
o This adaptation protects them from the
freezing winds.
o
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Adaptations for coping with
extreme temperatures
• Living in a hot environment
A camel can
more
than
It isdrink
very hot
and dry
in a
habitat.
Howtime.
do
100 litres ofdesert
water
at one
living things survive in a
o This allows it to go
for a long
desert?
distance without water.
o It also sweats and urinates very
little to retain as much water as
possible.
o A camel’s hump stores fat that
releases energy for the animal.
o
camel
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Adaptations for coping with
extreme temperatures
• Living in a hot environment
Some animals avoid the Sun’s heat by staying
underground or in the shade during the day.
o At night, when it is cooler, they come out to
hunt for food.
o
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Adaptations for protection
• Body coverings
Body coverings are adaptations to help
animals survive in their environment.
o Some body coverings are used to protect the
animals against the temperatures of their
environment.
o Others are used to protect the animals from
their predators.
o
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Feathers
• Feathers keep birds warm and help them
to fly.
• Some birds have to dive or swim in water
to find food.
• These birds have feathers which are
covered with a layer of oil that makes the
feathers waterproof and helps the bird to
float.
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Fur
• Some animals have a coat of thick, soft hair
called fur.
• In a very cold environment, the thick fur traps air
close to the animal’s body.
• This layer of air insulates the animal from the
cold and keeps the animal’s body at a constant
temperature.
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Scales, shells and spines
• Reptiles and most fishes have scales,
which can be smooth, rough or pointed.
fish scales
scales on
a snake
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Scales, shells and spines
• Other animals like turtles, snails and crabs
have shells to cover their bodies.
snail
crab
turtle
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Scales, shells and spines
• Hedgehogs, spiny anteaters and porcupinefish
have spines.
• Scales, shells and spines are hard and not
easily broken.
• So they act like armour to protect the animals
from their enemies.
• This is very useful for animals that
move too slowly to escape from
danger.
spiny anteater
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Camouflage
• Some animals cannot be easily spotted
because they blend in with their surroundings.
• This is an adaptation called camouflage.
• Camouflage gives animals a better chance of
survival as they are less likely to be eaten by
their predators and more likely to catch their
prey.
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Camouflage
• An example of camouflage is
that the fur and feathers of some
animals can change colour at
different times of the year.
• The fur or feathers can be white
during the winter months and in
shades of brown in the summer
months.
• This adaptation allows the
animal to blend in with its
different surroundings during
different seasons.
• Examples of these animals are
arctic foxes and arctic hares.
arctic fox
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Camouflage
• Other animals such as the
leaf insect and stick insect
have body shapes and
colours that blend into
their surroundings.
leaf insect
stick insect
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Camouflage
• Some animals have patterns that look like big
eyes on their bodies.
• These are called ‘eyespots’.
• Predators may mistake these eyespots as
belonging to that of larger creatures.
• As a result, the predators move away,
thinking they may become prey
themselves.
moth
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Adaptations for reproduction
Animals have to mate in order
to reproduce. Before they can
mate, they have to find a mate
or sexual partner.
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Reproduction in animals – finding
mates
• Body covering
Many animals have specialised ways of
attracting their mates.
o The males often have more colourful body
coverings than the males, which makes them
more attractive to the females who are looking
for mates.
o
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Reproduction in animals – finding
mates
• Body covering
The male peacock has a spectacular way of
attracting a female.
o It spreads out its tail feathers in a big,
colourful fan.
o After the mating season, the male peacock’s
tail feathers are no longer needed and they
drop off.
o
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Reproduction in animals – finding
mates
• Behaviour
The male frigate bird has
an inflatable red throat sac.
o It puffs the throat sac like a
huge balloon for long
hours.
o It also vibrates the throat
sac, claps its bill and
waves its wings to attract a
female.
o
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Reproduction in animals – finding
mates
• Lighting up
Animals that live in very dark places glow in
the dark to attract their mates.
o E.g. glow-worms
o
• Wingless females of a type of beetle
• The tip of the female’s abdomen glows in the dark
to attract the flying males to mate with her.
glow worm
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Reproduction in animals – finding
mates
• Lighting up
o
Fishes living in deep sea, where it is very
dark, have parts of their bodies that light up to
attract mates.
anglerfish
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Reproduction in plants – getting the
flowers pollinated
• Flowering plants need to be pollinated in order
to reproduce.
• During pollination, some flowering plants depend
on the wind to disperse their pollen grains.
• Most of them, however, depend on animals like
insects or birds.
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Reproduction in plants – getting the
flowers pollinated
• Adaptations of plants for pollination
Flowers that are pollinated by insects and
birds are usually large and colourful.
o They have nectar and a fragrance so that the
animals are attracted to them.
o
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Reproduction in plants – getting the
flowers pollinated
• Adaptations of plants for pollination
Flowers that are pollinated by wind are
usually small and plain.
o They are without fragrance as they do not
need to attract animals.
o
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Reproduction in plants – getting the
seeds dispersed
• Flowering plants have different adaptations to allow their
seeds to be dispersed as far away as possible.
• Dispersal methods:
tomato
coconut
saga love grass
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