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