Biodiversity and Ecosystems

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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 onstones
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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.
Minnows
Dragonfly larvae
Ducks
Tadpoles
Water fleas
Removing a species from a food web that has more
species is less disruptive.
Snails
Mosquitolarvae
Floatingalgae
Algae onstones
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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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