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Transcript Biodiversity_at_Risk1

Biodiversity at Risk
EQ: What are the various factors
that impact the biodiversity of our
Main Beach Laguna 1900
Renewable Resources
• Renewable
resources can
regenerate if it is
alive or replenish
itself if it is a
biochemical cycle
Solar energy
Nonrenewable Resources
• A nonrenewable
resource is one that
cannot be replenished
– Coal
– Oil
– Natural gas
Sustainable Resource Use
• This is a method of
resource use that allows
the renewable resources
time to replenish
• Limits the impact of
human activity on an
• One downfall is that it
usually costs more to be
ecologically responsible
than to deplete a
Land Resources
• This includes the space for
humans to live and work
• Also includes the soil in which
crops are grown
– If crops are rotated than the soil
can replenish the nutrients
needed to grow crops
– Soil becomes a nonrenewable
resource when allowed to erode
with wind and water or if it is overfarmed
– erosion can be prevented by
plowing the fields at different
times and by plowing in different
– Farmers often put up wind breaks
(trees) to prevent erosion by
Orange County circa 1961
Downsides of Agriculture
• With an increase in agriculture come some
– Clearing large amounts of land lead to the dust bowl
of the 1930’s
– With an increase in plants we have an increase in
insects that feed on them
– The use of pesticides have lead the extinction of
different organisms
– The use of river water for irrigation has diminished
natural water supply to many areas
– Genetically engineering of plants and insects has lead
to things like killer bees
Industrial Growth and
Urban Development
• People began to move to urban areas during the
industrial revolution because we now had means
to provide food for the masses
• These cities were fueled by fossil fuels
• The factories and masses of people discarded
their waste into the land and water surrounding
the cities
• Urban sprawl began – suburbs surrounding the
cities began to fill with the people needed to run
the factories
Forest Resources
• Wood from the forests is used to paper products
and for fuel
• Forests provide a habitat for many organisms
and provide a source of oxygen
• Old growth forests are those forests that have
never been logged and therefore often have the
richest ecosystems
• Loss of forests is called deforestation
– Leads to extinction of organisms, erosion, and
damage to the soil
– Sustainable forestry does not cut every tree and for
every tree they take one is planted in its place
Fishery Resources
• Most of the world receives sustenance from fish
• Taking fish faster than it can reproduce is called
– Between 1950 & 1990 the fish catch increased by 70
million fish
– If catch were to continue unregulated it could lead to
extinction of the different species
• Fish are now raised on fish farms to then either
be eaten or reintroduced into the environment to
• There is a strict limit on the catch of fish and
other sea food
– Limited by size and overall tonnage
Total World Fish Catch
In Tons
Fish Catch Per Person
In Kilograms
• This term refers to the overall variety of
organisms that live in an ecosystem
• Within each species there is genetic diversity
which allows species to adapt to environmental
changes and evolve
• Scientists have identified 1.5 million different
• Million more are yet to be discovered
– Estimated that 5 species go extinct every minute as
we destroy the different habitats
• This diversity allows us to get all of the nutrients,
supplies and inventions that we need to live
Threats to Biodiversity
• Habitat alteration
– The building of cities and farms destroys habitats
forcing animals to find other places to live
– Fragmentation of wild space cuts off food and mates
• Demand for Wildlife Products
– The hunting of animals for their fur, blubber and tusks
have pushed many organisms almost to extinction
– Animals that are considered endangered are now
protected against this type of hunting but these laws
are difficult to enforce
• Most dangerous to
the tops of the food
chains due to
– This is where
pesticides and other
forms of pollution build
because of the amount
of lower level
organism that need to
be eaten for food
Small Fish 100,000
Zooplankton 10,000
Producers 1000
Bioaccumulation vs. Biomagnification
• Bioaccumulation is
the accumulation
of pollutants by an
organism of a
species or a single
• Biomagnification is
the accumulation
of pollutants
through a food
chain. It’s the
opposite of energy
transfer through an
energy pyramid.
Introduced Species
• This refers to organisms that are
transported into an area through human
• These species often become invasive –
reproducing quickly and out competing
native species for limited resources
• Often lack predators in their new habitat
Conserving Biodiversity
• Many efforts in conservation are aimed at
preventing individual species from going extinct
– These efforts include laws against hunting, zoo
reproduction and habitat preservation
• Some countries are attempting to preserve
– These create islands of genetic isolation that do not
do all that good
– These islands are national forests and preserve land
– Our local example is O’Neil park
Frozen Zoo
• San Diego, Ca