Transcript Biological Diversity, Human Impacts, Conservation

Human Impact on Ecosystems
Biodiversity
• Refers to the variety of life in an area
Why is Biodiversity important? It’s
not just about the aesthetics…
Life depends on life…
*biodiversity brings stability to an
ecosystem
*living things create niches for other living
things; more living things,
more niches…
*symbiotic relationships can be effectively
established or maintained
*effective food webs can be established or
maintained when there are
more orgs
Importance of Biodiversity to
humans?
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Production of oxygen and carbon dioxide
Wider choice of Diet
Prevention of starvation
Cross-breeding can happen more easily,
making stronger, hardier organisms
• More Materials for clothes, furniture,
buildings
• More medicines
Loss of Biodiversity –
extinct vs. endangered vs. threatened
• Extinct – no orgs of that species exist
• Endangered -- population of organisms which is at risk
of becoming extinct because it is either few in numbers,
or threatened by changing environmental or predation
parameters
• Threatened -- any species which is likely to become
endangered within the foreseeable future throughout all
or a significant portion of its range
Threats to Biodiversity:
1. Habitat loss/destruction
(this one is the number one concern!)
2. Habitat fragmentation
3. Habitat degradation
4. Introduction of Exotics/Invasive
Species
Threats to Biodiversity
• Habitat loss – destruction of area
*deforestation
*clear-cutting grasslands
*draining wetlands
• Habitat degradation
(damage to habitat by pollution)
Pollution: any undesirable factor that is
added to air, water or soil.
*3 types of pollution:
air, land, water
Air pollution
-greatest source of air pollution is the
burning of fossil fuels
*Smog: can create breathing problems -asthma; irritates lining of mouth
and nose
*acid precipitation (acid rain); pH drops
*damage to ozone layer – natural filter for uv
radiation is being lost
*Global warming due to greenhouse effect
Global warming
• http://www.youtube.com/watch?v=oJAbAT
JCugs
• See page 490-492 in textbook….
Water Pollution
• Additions of solid or liquid waste that is not
naturally occurring in a body of water
Ex. Excess fertilizer and animal waste wash
into streams, rivers, lakes, ponds, and
oceans cause
ALGAL BLOOMS
Algal Bloom: freshwater
river
9-23-1999
9-29-1999
Red Tide – oceanic algal
bloom
Indicator species
• Also knows as bioindicator
• Species that provides a sign or indication
of the quality of the ecosystem’s
environmental conditions
Ex. amphibians
http://www.youtube.com/watch?v=u6gW1m1reI
Land Pollution
• Trash, garbage, and litter
*average American produces ~1.8 kg
of solid waste daily
• Pesticides: increase in concentration of a
substance (toxin) from one link in a food
chain to another –
• causes BIOMAGNIFICATION in food web
• Ex. DDT effects on eagles
Page 495
DDT and eagle eggs…
Introduction of
Exotic species or Invasive Species
• “Exotic” meaning not native to an area
• Problem is that there are NO NATURAL
PREDATORS, so the new species grows
unchecked and can get out of control
• Ex. Kudzu, fire ants, zebra mussels
Kudzu covers EVERYTHING –
even other plants!
Zebra mussels
Fishzilla video clip
• http://channel.nationalgeographic.com/cha
nnel/videos/fishzilla-snakehead-invasion/
Conservation Biology
• Studies methods and implements plans to
protect biodiversity.
• Effective plans are based on principles of
ecology
• HUMANS ARE HUGE PART OF THE
PROBLEM, so education is a key part of
conservation biology…
Biologist, Writer, Ecologist
Figure 50.3 Rachel Carson
Silent
Spring
"The more
clearly we can
focus our
attention on
the wonders
and realities
of the
universe
about us,
the less taste
we shall have
for
destruction."
-- Rachel Carson © 1954
Legal protection of species
• 1973 – U.S. Endangered Species Act put
into effect
Source: http://ecos.fws.gov/tess_public/StateListing.do?state=all = updated daily
Preserving Habitats
• Nature preserves
1872, first national park – Yellowstone
• Sustainable use – strives to let people use the resources
of wilderness areas in ways that will not damage the
ecosystem
Ex. Eskimos hunting seal and walrus in Alaska
Global fisheries – page 503
*rotation of species to catch
*fishing gear review
*harvest reduction
*fishing bans
• Habitat corridors – natural strips that
allow the migration of organisms from
one area to another
Reintroduction Programs vs.
Captivity
• RIP -- Release orgs into an area where
their species once lived
• Captivity – org that is held by people;
reintroduction of these orgs is VERY
difficult, if not impossible
Precautionary Principle
• In situations where absolutes are not
known but problems are suspected:
Set the acceptable levels of the
suspected substance conservatively
low, and keep them there unless future
studies show that they can be safely
raised.
Importance of recycling, reusing
• CUT DOWN ON SOLID WASTE that will
be left behind
• Use biodegradable materials that will
decay
• Recycle materials that WON”T decay for
other uses
• BE AWARE!