Transcript Biodiversity and Ecosystems

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What is the advantage of many plants
and animals living in the same area?
Biodiversity and
Ecosystems
In this presentation you will:
 explore biological diversity and ecosystem
sustainability
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Introduction
The ability of an
ecosystem to
remain, and of life
to continue despite
changing conditions,
is called its
sustainability.
One of the most
important factors of
ecosystem sustainability
is the variety of species
that inhabit the ecosystem.
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Ecosystem Sustainability
Today, there are
millions of
species of living
things on Earth.
This variety of
living things is
known as
biological
diversity, or more
commonly,
biodiversity.
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What is Biodiversity?
Biodiversity is the variety of life both within and
between species and includes the diversity of:
 Species
 Genetic material
It also includes the
diversity of
ecosystem types.
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Question 1
Which of the following best describes biodiversity?
A) The variety of species, genetic material, and
ecosystems found on Earth
B) The number of trees in a forest
C) The sizes of fish in a stream
D) The dependence of one species on another
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Question 1
Which of the following best describes biodiversity?
A) The variety of species, genetic material, and
ecosystems found on Earth
B) The number of trees in a forest
C) The sizes of fish in a stream
D) The dependence of one species on another
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Species
Species diversity is the number of different species
of plants and animals that live in an ecosystem.
The more variety of
species, the more
organisms there will be in
food chains and webs.
This makes an ecosystem more stable and less
likely to be disrupted by changes in numbers of
one species.
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Species Diversity
An increase or reduction
in a particular species
changes the dynamics of
an ecosystem.
An ecosystem that is
stable will be more able
to tolerate this change.
When diversity is low, change can cause vital
elements of an ecosystem, such as the food chain,
to collapse. The ecosystem would fail.
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The Food Chain
Consider this food chain.
What would happen to the
ducks if the snails were
wiped out by disease?
Ducks
The ducks would suffer too.
Snails
With more species in the food
web, the outcome for the ducks
may not be the same.
Algae on
stones
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The Food Web
Now consider the effect of removing the snails.
The ducks would
not be as affected
since they can still
eat mosquito
larvae.
Dragonfly larvae
Ducks
Tadpoles
Removing a
species from a
food web that has
more species is
less disruptive.
Minnows
Snails
Algae on
stones
Water fleas
Mosquito
larvae
Floating
algae
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Genetic Material
Genetic diversity is the variety of all the genetic
material that is present in organisms.
Varieties in inheritable
characteristics give rise
to adaptations in
species, including
resistance to disease.
It makes a species more
able to cope with changes
to the environment.
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Question 2
Why is diversity of genetic material important to the
stability of ecosystems?
A) It enables species to adapt to and cope with
changes in the environment.
B) It prevents species being part of the food chain
so that they live longer.
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Question 2
Why is diversity of genetic material important to the
stability of ecosystems?
A) It enables species to adapt to and cope with
changes in the environment.
B) It prevents species being part of the food chain
so that they live longer.
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Why is Biodiversity Important?
Biodiversity keeps ecosystems healthy and stable
and enables them to function for a long time.
Healthy, long lasting ecosystems are essential to our
planet.
 They keep gases like
oxygen and carbon dioxide
in the air stable.
 They recycle nutrients.
 They keep our climates stable.
 They keep the earth stable by
controlling erosion.
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Why is Biodiversity Important?
Ecosystems are also very important
to the way we live our lives.
Plants and animals
provide us with:
 Food
 Shelter
 Fuel
 Materials
 Clothing
 Medicines
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Preserving Biodiversity
Biodiversity of ecosystems is essential to preserve
the quality of life we have on Earth.
The loss of species will
lead to a loss of many
of the resources that
are valuable to us.
Our climates and
atmosphere could change
in a way that makes it
difficult to live.
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Question 3
Biodiversity is very important for which of the
following reasons?
A) It keeps ecosystems stable.
B) It preserves resources that are valuable to us.
C) It keeps the conditions of the planet suitable for
humans to live.
D) all of these reasons
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Question 3
Biodiversity is very important for which of the
following reasons?
A) It keeps ecosystems stable.
B) It preserves resources that are valuable to us.
C) It keeps the conditions of the planet suitable for
humans to live.
D) all of these reasons
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Threats to Biodiversity
Human activity is one of the biggest threats to
biodiversity.
We rely on natural resources,
but by overusing them we
can damage and upset the
balance of ecosystems.
For example, global warming
causes melting of ice caps and
affects all living things that
rely on them.
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Threats to Biodiversity
We are changing the
varieties of species
through advances in
genetics and selective
breeding.
We sometimes introduce
species into areas they are
not usually found. This can
affect the species that
already live there.
The gray squirrel was introduced to
the UK and now outnumbers the
British red squirrel
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Question 4
"The introduction of new species to a habitat could
never be a cause of reduced biological diversity.”
Is this statement true or false?
Answer true or false.
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Question 4
"The introduction of new species to a habitat could
never be a cause of reduced biological diversity.”
Is this statement true or false?
Answer true or false.
False
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Summary
In this presentation you have seen:
 the meaning and importance of biodiversity
 the threats to biodiversity
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