Transcript Populations, Competition, Predation, Migration

POPULATIONS
Population size
• A population is the number of
a species living in a particular
area
What factors could change a
population?
• Competition
• Predation
• Migration
• Disease
• Natural
disasters
• War
• For food, water and space
• Predators will eat prey and reduce the
population (including the number of
offspring)
• Members of the population may leave
the area
• A disease could kill some of the
population
• Drought, fire, floods, volcanic eruptions
etc could alter the habitat and affect the
population
• Wars can result in the death of many
members of a population
What else can affect the numbers
and the distribution of a population?
• How well are individuals
adapted?
• This will affect their
survival in a habitat.
• What else lives there?
This may mean
competition for food.
• There may be
predators.
What is adaptation?
• Adaptation describes how a plant
of animal is able to survive in
various environments
• Well adapted organisms can cope
with the different aspects of
their environment, for example,
the temperature
It is always a struggle for plants
and animals to survive
ANIMALS STRUGGLE :
• For food
• For water
• For protection
against weather
• Against being eaten
by predators
• Against disease
• Against accidents
PLANTS STRUGGLE:
• For water
• For light
• For minerals in the
soil
• Against weather
• Against disease
• Against being eaten
How does adaptation help
organisms?
• Well adapted organisms are better at
coping with extremes of weather
• They are better at competing for
food
• They are better at escaping from
predators
• They are more likely to survive in
their habitat and produce offspring
An arctic habitat
• This sort of
habitat can have
extremely low
temperatures
• The ground is
covered with
white snow for
most of the year
How are animals adapted
to survive in the Arctic?
• Animals like polar
bears will have a
thick insulating coat
• They usually have a
large amount of body
fat
• They have a large
body size to surface
area ratio
• They have a
How do these adaptations
help?
 A thick fur
coat
 Traps heat to keep
warm
 Large body size  Reduces heat loss by
to surface area
radiation
ratio
 A large amount  Acts as a food store
of body fat
and to keep warm
 Camouflage
 White fur is good
A desert environment
• A desert can have
very little rainfall
• There is a lot of
sunshine during the
day
• There is very little
shade
• The temperatures
can get very hot
• At night it can
become very cold
How is a camel adapted to
survive in the desert?
• Camels can store large
amounts of water in
the fat in their humps
• They have feet with a
large surface area to
allow them to walk on
sand
• They also have long
eye-lashes to stop
sand blowing into their
eyes
How do reptiles survive in the
desert?
• Most reptiles will find some
shade under a rock during
the hottest part of the day
• When walking on hot sand a
lizard will try to touch the
ground with only a small
area
• This lizard keeps swopping
feet, and only stands on
two feet at a time
• This snake keeps a loop of
itself off the ground as it
moves across the sand
How do plants survive the
desert?
• A cactus has a long tap
root to reach water
deep under the ground
• It has a thick, fleshy
stem to store water
• It has needle-shaped
leaves to prevent water
loss through the
stomata
• The needles help to
stop animals from
eating it
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www.worldofteaching.com
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completely free site and requires no registration. Please
visit and I hope it will help in your teaching.