Biodiversity at Risk
EQ: What are the various factors that impact the biodiversity of our environment?
Main Beach Laguna 1900
Renewable Resources
• Renewable resources can regenerate if it is alive or replenish itself if it is a biochemical cycle– Plants– Solar energy– Wind– Animals– water
Nonrenewable Resources
• A nonrenewable resource is one that cannot be replenished naturally– 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 environment
• One downfall is that it usually costs more to be ecologically responsible than to deplete a resource
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 over-farmed
– erosion can be prevented by plowing the fields at different times and by plowing in different directions
– Farmers often put up wind breaks (trees) to prevent erosion by wind
Orange County circa 1961
Downsides of Agriculture
• With an increase in agriculture come some challenges– 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
http://www.history.com/topics/dust-bowl
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
over-fishing– 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 reproduce
• There is a strict limit on the catch of fish and other sea food– Limited by size and overall tonnage
Total World Fish Catch Fish Catch Per Person
In Tons In Kilograms
Biodiversity
• 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 species
• 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
Pollution
• Most dangerous to the tops of the food chains due to bioaccumulation– 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
10,000,000
100,000
10,000
1,000,000
1
1000
LargeFish
Small Fish
Zooplankton
Producers
Water
Bioaccumulation vs. Biomagnification
• Bioaccumulation is the accumulation of pollutants by an organism of a species or a single species
• Biomagnification is the accumulation of pollutants through a food chain. It’s the opposite of energy transfer through an energy pyramid.
PacMan
Introduced Species
• This refers to organisms that are transported into an area through human activities
• 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 habitats– 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