Biodiversity

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Biodiversity
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What is Biodiversity?

• Biological Diversity or Biodiversity

The variety of life in all its forms, levels and
combinations. Includes ecosystem diversity,
species diversity, and genetic diversity (IUCN,
UNEP and WWF, 1991).
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Biodiversity

• Biodiversity is currently declining

• Species
• are going
• extinct

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Extinction

• Extinction is a natural process

99 of all species have become extinct
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Extinction

• Natural Extinction

• Typically occurs at slow pace

A few species disappearing over long time periods
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Extinction

• Natural Extinction

• though there have been rapid, mass extinctions

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Extinction

• Accelerated Extinction

• Occurring at a rapid pace

Many species are disappearing every year
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Extinction

• Natural Extinction

• Often old species evolve into new species over
  time

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Extinction

• Natural
• Extinction

• Offspring species survive and continue to evolve

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Extinction

• Accelerated Extinction

Species are disappearing too rapidly to evolve
into new species
No evolutionary or genetic legacy remains
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Extinction

• We are currently experiencing the greatest
  extinction event of the last 65 million years
  since the disappearance of the dinosaurs
• Peter Raven

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Biodiversity

• How many species have been identified ?

Approximately 1.4 million species have been
named and described
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Biodiversity
Insects 750,000

• Vertebrates
• Mammals 4,000
• Birds 9,000
• Reptiles 6,300
• Amphibians 4,200
• Fish 19,000

Plants 250,000
Non-insect arthropods 125,000
Other species 200,000
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Biodiversity

• How many species have been thoroughly studied ?

Only 1 - 2
We have done little more than name most of the
species that we know about
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Biodiversity

• How many species are currently alive on Earth ?

We do not know !
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Biodiversity

• How many species are currently alive on Earth ?

In the past, estimates were 3 5 million species
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Biodiversity

• How many species are currently alive on Earth ?

Recent estimates are more than 10 million species
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Biodiversity

• How many species are currently alive on Earth ?

The higher numbers of more recent estimates are
due to recognition of vast, unknown biodiversity
in tropical rainforests
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Biodiversity

• How many species are currently alive on Earth ?

Many species will disappear before we can even
identify and name them
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Biodiversity

• What is the primary cause of the current high
  rates of extinction of species ?

Habitat Alteration
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Habitat Alteration

• The most significant single factor in extinctions

• Habitats are destroyed as human societies alter
  ecosystems

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Habitat Alteration

• Rainforest destruction threatens countless
  species

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Habitat Alteration

• Human activities have significantly altered an
  estimated 50-75 of the ice-free land surface of
  the Earth

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Habitat Alteration

• Will Global Climate Change be the greatest
  habitat alteration of all?

According to the IPCC, a warming of 1.5 2.5 0C
would place 20 - 30 of species at increased risk
of extinction
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Habitat Alteration

• Will Global Climate Change be the greatest
  habitat alteration of all?

According to the IPCC, a warming above 3.5 0C
would place 40 - 70 of species at increased risk
of extinction
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Human Pressures on Species

• Habitat Alteration
• - most important by far -

Other pressures include

• Commercial Hunting and Poaching

• Introduction of Alien Species

• Pest and Predator Control

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Human Pressures on Species

• Commercial hunting and fishing have resulted in
  decline of whales, sea turtles, and other species
  

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Human Pressures on Species

• Poaching threatens elephants, rhinos and other
  species

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Human Pressures on Species

• Introduction of alien species and diseases often
  threatens native species

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Human Pressures on Species

• Efforts to control pests and predators can harm
  species and ecosystems

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Vulnerability of Species

• Ecological factors make some species more
  vulnerable to extinction

• Critical population size

• Limited geographic range

• Dietary specialists

• Larger size species

• Tolerance to human presence

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Vulnerability of Species

• Critical population size

• Once a population falls to a small number,
  particularly a social species, the population may
  not be able to recover

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Vulnerability of Species

• Limited geographic range

• Species with a small geographic range are more
  vulnerable to extinction than are geographically
  widespread species

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Vulnerability of Species

• Dietary specialists

• Species with highly specialized diets are more
  vulnerable to extinction than are dietary
  generalists

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Vulnerability of Species

• Larger size species

• Larger species more directly compete with humans

• Larger species tend to have lower reproductive
  rates

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Vulnerability of Species

• Tolerance to human presence

• Some species do not tolerate human presence and
  will not inhabit areas where humans are found

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Reasons for Concern

• Biodiversity is Rapidly Declining

Why should we care and be concerned ?
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Reasons for Concern

• Ethics

• We have the power to destroy or save species

• It is wrong for us to destroy other species

• It is right for us to save other species

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Reasons for Concern

• Aesthetics

• The diversity of species gives beauty to our
  world and the experiences of life

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Reasons for Concern

• Economics

• A tremendous portion of our economy depends on
  biological species

• Species extinctions deny us potential economic
  opportunities

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Reasons for Concern

• New Medicines

• Many of our medicines are based upon biological
  species

• Species extinctions deny us potential new
  medicines

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Reasons for Concern

• New Foods

• All of our foods are based on biological species

• Species extinctions deny us potential new foods

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Reasons for Concern

• Ecosystem Stability

• Complex ecosystems with greater species
  diversity are more stable over time

• Species extinctions makes ecosystems less
  complex and less stable

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Reasons for Concern

• Future Generations

• We must preserve the biological wealth of the
  Earth for the sake of our children,
  grandchildren, and countless future generations

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