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Biodiversity, Endangered Species, and Extinction


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Title: Biodiversity, Endangered Species, and Extinction

Biodiversity, Endangered Species, and Extinction
  • APES
  • October 2004

What is a species and how many are there?
  • A species is a group of organisms that resemble
    one another in appearance, behavior, chemistry,
    and genetic make-up
  • The true test to determine if two individuals are
    members of the same species is to see whether or
    not viable (fertile) offspring can be produced
    under natural conditions
  • We dont know how many exist on earth
  • 1.5 to 1.8 million identified
  • Estimates (save bacteria) are 3 to 100 million
  • Most common are insects and plants

What is biodiversity
  • A renewable resource
  • The different forms of life and life sustaining
    processes that can best survive the variety of
    habitats on earth
  • Four different types fall under biodiversity
  • Genetic Diversity
  • Species Diversity
  • Ecological Diversity
  • Functional Diversity

Why is biodiversity important?
  • The rich variety of genes, species, biological
    communities, and life sustaining processes
  • Give us wood, fibers, energy, raw materials,
    industrial chemicals, medicines etc that fuel our
    economies (estimated _at_ 37 trillion/yr)
  • Purify our water, air, soil
  • Decompose our organic and chemical wastes
    recycle nutrients
  • Natural pest control and pollination
  • Regulate climate, protect us from harmful
  • Production of all food
  • Prevent soil erosion/flood control
  • Detoxification of human and industrial wastes

Who cares!? Its just one species!
  • Every species today contains genetic information
    that represents millions of years of evolution
    and adaptation to earths changing environmental
  • This diversity also represents the raw materials
    for future adaptations if environmental
    conditions change
  • In other words, biodiversity is lifes insurance
    policy against natural disaster!
  • Loss of biodiversity
  • Reduces the availability of ecosystem services
  • Decreases ability of species and ecosystems to
    adapt to changing environmental conditions

BiodiversitySpeciation minus extinction
  • When environmental conditions change, a species
    must either
  • Evolve (become better adapted) OR
  • Move to a more favorable environment OR
  • Cease to exist (become extinct)
  • Extinction is the ultimate fate of all species
    just as death is ultimate fate of all individuals
  • 99.9 of all of the species that have ever
    existed are now extinct!
  • Background Rate vs. Mass Extinctions

Extinctions over time
Are humans currently causing a mass extinction?
  • During 20th century, it has been estimated that
    the extinction rate has increased 100 to 1000
    times the natural background rate
  • We already use 27 of earths NPP
  • 75 of habitable area disturbed
  • World wide forest cover reduced by 20-50
  • More than half of wetlands of the world
  • On our time scale, the loss of these species
    cannot be recouped by formation of new species
    (b/c this takes a long time)
  • Genetic engineering wont solve this (why?)

Human Impacts on Extinction Rates
  • Before humans, estimated rate was one species per
    million ( 0.0001 per yr)
  • Now, best guess is 0.1 per yr (1000X background
  • If the rate is as high as 1 as some believe
    (E.O. Wilson), then 20 of current animal and
    plant species could be gone by 2030 and 50 gone
    by the end of this century
  • At this rate, it will take at least 5 million
    years for speciation to rebuild the diversity we
    destroy during this century.

Premature Extinctions Caused By Human Beings
Nature Conservancy Study 539 extinctions since
Underlying Causes of Extinction
Human Impacts on Ecosystems
  • Fragmenting and degrading habitat (stop)
  • e.g. Tropical forests being cut at a rate of 0.6
    to 2 per year
  • Half of remaining forests lost or degraded in 25
    to 83yrs
  • Simplifying natural ecosystems
  • Creating monocultures
  • Using, wasting, or destroying an increasing
    percentage of earths NPP (27 of total)
  • Strengthening some populations of pest species
    and disease causing bacteria by causing genetic
    resistance through overuse of pesticides
  • Eliminating some key predators
  • Deliberately or accidentally introducing exotic
  • Over harvesting of renewable resources
  • Interfering with normal cycling and flows of
    energy in ecosystems

Habitat Loss
Poaching often Extinction
Endangered vs. Threatened
  • Endangered
  • So few left that species could soon become
    extinct over all or most of its range
  • Threatened
  • Still relatively abundant but b/c of declining
    numbers is likely to become endangered in the
    near future
  • WWF study 30k Under threat of extinction
  • 34 of worlds fish
  • 25 of worlds amphibians
  • 24 of worlds mammals
  • 20 of worlds reptiles
  • 14 of worlds plant species
  • 12 of worlds bird species

Endangered and Threatened Part I
Endangered and Threatened Part II
Endangered and Threatened Part III
What makes a species vulnerable to extinction?
  • Specialized niche
  • Low reproductive rate
  • Blue whales, giant panda, rhinoceros
  • Feeds at high trophic level
  • Bengal tiger, bald eagle
  • Fixed migratory patterns
  • Blue whale, whooping crane, sea turtles
  • Commercially valuable
  • Snow leopard, tigers, elephants, rare birds,
  • Rare/Narrow Distribution (island species)
  • Need Large Territory
  • Condor, Florida panther

Types of Extinctions
  • Local
  • No longer in an area it once inhabited
  • Ecological
  • So few left that it cant do its job
  • Biological
  • No longer found anywhere on earth

Status of Biodiversity
Hot Spots of Biodiversity in the USA
Why preserve wild species?
  • Economic goods
  • Food, fuel, lumber, fiber, paper, etc
  • 40 of all medicines and 80 of top 150
    prescription drugs in USA derived from living
  • Crops domesticated from wild plants
  • Need genetic diversity to develop future crops
  • Ecological services
  • Genetic information
  • Recreation
  • Eco-tourism
  • 1 male lion living to age 7550K or 1000 if
    killed by a poacher for its skin
  • Ethical considerations

Preserving Biodiversity
US Endangered Species Act (1973Nixon!)
  • Provides a program for the conservation of
    threatened and endangered plants and animals and
    the habitats in which they are found
  • Dept of Interior maintains the list of 632
    endangered species (over 50 plants) and 190
    threatened species
  • Anyone can petition the US FWS to add a species
    to the list (if it is in danger of extinction in
    all or most of its range)
  • Can be listed b/c of habitat destruction,
    overexploitation, disease/predation, inadequacy
    of existing regulations, any human threat to its
    continued existence
  • Law prohibits any action (either administrative
    or real) that results in the taking of a
  • Illegal to take, possess, sell, transport listed
  • Recovery Plan is written for each species
  • Provides for acquire land that preserves these

  • Convention on International Trade In Endangered
  • Is an international agreement between
    Governments. Its aim is to ensure that
    international trade in specimens of wild animals
    and plants does not threaten their survival
  • Annually, international wildlife trade is
    estimated to be worth billions of dollars and to
    include hundreds of millions of plant and animal
  • The trade is diverse, ranging from live animals
    and plants to a vast array of wildlife products
    derived from them, including food products,
    exotic leather goods, wooden musical instruments,
    timber, tourist curios and medicines.
  • Levels of exploitation of some animal and plant
    species are high and the trade in them, together
    with other factors, such as habitat loss, is
    capable of heavily depleting their populations
    and even bringing some species close to
  • Many wildlife species in trade are not
    endangered, but the existence of an agreement to
    ensure the sustainability of the trade is
    important in order to safeguard these resources
    for the future.
  • Voluntary adherence
  • CITES works by subjecting international trade in
    specimens of selected species to certain
    controls. These require that all import, export,
    re-export and introduction from the sea of
    species covered by the Convention has to be
    authorized through a licensing system.
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