Transcript Biological Diversity - Life Sciences Outreach at Harvard University

Summer 2010 Workshop
in Biology and
Multimedia
for High School Teachers
David Eatough
Harvard University Life Sciences HHMI Outreach Summer 2010
What is Biodiversity?
Biodiversity is the variety or richness of life
at all structural levels (molecular/genetic,
species, ecosystem). It is an essential
renewable resource. It is exploited and
depleted as a result of the “Tragedy of the
Commons” phenomenon. The current rate of
biodiversity loss is comparable to previous
extinction events.
Why is biodiversity important?
Biodiversity provides us with:

Natural Resources (food, water, wood,
energy, and medicines)

Natural (Ecosystem) Services including:
air and water purification, soil fertility,
waste disposal, pest control)

Aesthetic pleasure
“The decline of Earth’s biodiversity is an unintended consequence of
multiple factors that have been enhanced by human activity. They
can be summarized by the acronym HIPPO, with the order of the
letters corresponding to their rank in destructiveness.”
H
Habitat loss, including that caused by
human-induced climate change.
I
Invasive species (harmful aliens,
including predators, diseases, and
competitors that displace native species
P
Pollution
P
Population, Human overpopulation to be
exact, a root cause of the other four factors
O
Overharvesting, Overuse (hunting,
fishing, gathering)
E. O. Wilson “The Creation”
Habitat loss/destruction
http://en.wikipedia.org/wiki/File:Lacanja_burn.JPG
Habitat loss is the greatest
reason for biodiversity loss.
Habitat loss is due to:
• Conversion of natural
areas to farms, houses,
etc
• Fragmentation of
ecosystems by human
activities, housing,
transportation,
agriculture etc.
• Simplification of genetic
diversity and complex
ecosystems by
planting/selecting
monocultures.
Invasive / Exotic Species
Invasive, exotic species introduced from
elsewhere outcompete native species
because they:
Have no natural predators
Colonize disturbed habitats quickly
Have a high biotic potential (r-species)
http://en.wikipedia.org/wiki/File:Kudzu_on_trees_in_Atlanta,_Georgia.jpg
http://en.wikipedia.org/wiki/File:Bufo_marinus_from_Australia.JPG
Cane Toads – The Conquest movie
Pollution
Pollution (Oil spills, human agricultural waste,
fertilization, pesticides, acid deposition,
greenhouse gases etc) caused by human
activities has a negative effect on biodiversity
http://en.wikipedia.org/wiki/File:AlfedPalmersmokestacks.jpg
Population, Human overpopulation that is.
6.8 Billion and counting. The expansion of human
population and affluence, especially in the
developing world harms natural ecosystems.
http://en.wikipedia.org/wiki/File:World_population.svg
Overharvesting, Overuse, Overexploitation
Overhunting, overfishing, destructive
harvesting practices (cyanide, dynamite),
illegal trade, exotic pet industry
http://en.wikipedia.org/wiki/File:Fishing_down_the_food_web.jpg
Raven, Berg, and Hassenzahl put it this way
Human
Population
Increase
Land use change
(Habitat loss)
Increasing
Economic
Activity
Increasing
Economic
Activity
Increased use
of technology
Increased use
of technology
Social, political
and cultural
factors
Social, political
and cultural
factors
Indirect
(Underlying
causes)
Direct
causes
Declining
Biological
Diversity
Characteristics shared by many
endangered species include:
•
•
•
•
Low reproductive rate (biotic potential)
Feed at high trophic levels (apex predator)
Large body size
Specialist
Specialized feeding habits
Specialized nesting and/or breeding areas
Fixed migratory patterns
Found in one place or region
• Rare
• Commercially valuable
• Negative human interactions including
attacks on people or livestock
How can
humanity
protect
biodiversity?
http://en.wikipedia.org/wiki/File:Siproeta_epaphus_Galawebdesign.jpg
Important Laws Protecting Biodiversity
Lacey Act (1900) forbids interstate commerce of illegally
killed wildlife. Modifications of act prevent importing
dangerous non-native species.
Endangered Species Act (ESA) of 1973 makes it illegal to
kill, trap, uproot (plants), modify the habitat of, or engage in
commerce of an endangered species or its parts.
To designate a species as endangered or threatened, Fish
and Wildlife Service or National Oceanic and Atmospheric
Administration must:
• List species
• Designate critical habitat areas where species is found
• Develop a recovery plan to help species survive and thrive
The rich variety of the natural world that Charles Darwin memorably
imagined as an "entangled bank", and that E. O. Wilson labeled
"biodiversity", is in crisis. The International Union for Conservation of
Nature (IUCN) calculates that one-fifth of mammals and nearly
one-third of amphibians are threatened with extinction. Some
estimate that only half of the species alive today will survive to
2100. Others describe the pace of biodiversity loss as 100 times the
rate of natural extinctions. Less-diverse ecosystems are less
productive, less stable and less robust. So loss of biodiversity may
weaken ecosystems and make them more fragile, especially in the face
of climate change, with grave consequences for food security, among
other things.
Sara Abdulla,
Chief Commissioning Editor, Nature
March 2010
http://en.wikipedia.org/wiki/File:MEAConservationStrategies.jpg
This summary of the
relative effects by the year
2100 is a composite derived
from calculations carried
out for 12 individual
terrestrial and freshwater
ecosystems by O. E. Sala et
al. (Science287, 1770–1774;
2000). Overall, changes in
land use constitute the main
estimated impact on
biodiversity, but the
pattern varies considerably
for different ecosystems.
According to Sala and
colleagues' calculations,
climate change will have the
strongest effect on Arctic,
alpine and boreal
ecosystems, whereas biotic
exchange (that is, invasion
by non-native species) will
exert its main influence in
lakes.