Transcript Earth - One Enormous Ecosystem

Earth - One Enormous
Ecosystem
Biodiversity and
Environmental Health
Pa Standard 4.12.3.B
Ecology
• The study of interactions between
organisms and their environments.
• Looks at the fine balance between biotic
and abiotic factors
Principles of Ecology
1. Everything is related to everything else.
• Example

A decrease in the mosquito population
seems beneficial to humans, but the
absence of these insects disrupts the food
chain (tadpoles and fish)
Principles of Ecology
2. Everything must go somewhere.
Think of sewage treatment worksheet….
Example:
Bald eagle and DDT
Principles of Ecology
3. Nature knows best.
We must share the planet with the rest of the
biosphere.
Our small changes in the environment are
more likely to do more harm than good.
Aldo Leopold
• A famous ecologist
that stressed humans
must live in harmony
with the Earth, and
whatever is taken
from the Earth is
simply borrowed.
Nonpoint source pollutants
(NPS) pg 133
• These pollutants are carried far from their
source by rain and melting snow.
• Ex: fertilizers, pesticides, oil, grease,
sediment, bacteria, and nutrients
• Can you think of where these originated?
NPS
• Is the leading cause of water quality
problems throughout the US.
• Responsibility of reducing the amount of
NPS falls on government and State hands.
How can we reduce the
amount of NPS?
• Keeping litter, pet wastes, leaves, and
debris out of the street gutters which
channel directly into watershed bodies.
• Use lawn fertilizers sparingly
• Dispose of household chemicals properly
• Control erosion by planting groundcover
Point Source Pollutants (PS)
Pg 133
• Pollutants that are discharged or emitted
from an identifiable source.
• Ex: output from factory pipes, leaking
landfills, slaughter houses
• In 1996, PA ranked in the top 10 states for
PS emissions.
PS
• Legislation has helped reduce the amount
of PS in PA.
• Some factories have taken their own
initiative to reduce their PA more than is
required by law.
Chesapeake Bay
Detecting pollutants
• Hazardous waste: seismic vibrations to
cast images of waste material underground
• Air: continuous emission monitoring
system(CEMS) measures the gas or
particulate matter
• Researchers are working to develop state
of the art devices to detect pollutants more
efficiently.
Natural events &
Environmental Health
• El Nino is a disruption in the relationship
between Earth's hydrosphere and
atmosphere system in the tropical Pacific
Ocean.
El Nino
• Occurs about every 4 years
• Results in floods, droughts, hurricanes
• Can also disrupt the ecosystem around the
world.
El Nino
• Trade winds blow east to
•
west, increase in warm
water in the Pacific
To replace this water, cold
nutrient rich waters rise
from the deep ocean
along the coast of S
America which feeds a lot
of marine life.
• During El Nino, the
•
trade winds die down
and the water built up
in the western Pacific
migrates westward.
The nutrient rich
waters do not rise up
which causes many
marine kills.
Volcanic eruptions
• Send tons of gases, ash, and dust high
into atmosphere
• In 1991, Mt Pinatubo in the Philippines
erupted
 30 million tons of SO2 into air which formed
suspended particles in the air that spread
rapidly around the globe.
Mt Pinatubo eruption
• This caused cooler climates in the Northern
•
•
•
Hemisphere due to decreased sunlight for years.
Caused a large hole in the ozone layer in the
Southern Hemisphere.
Satellites tracked the ash cloud as it moved
several times around the globe.
Still there are hot spots left from the volcanic
debris
Biodiversity & Environmental
Health
• Biodiversity: the variety of living organisms on
Earth
• When a ecosystem is in equilibrium, the number
of species is balanced by the resources and vice
versa.
• The removal of 1 species can disrupt the entire
system.
Biomonitoring
• Monitoring an ecosystem’s health by using
biological factors.
• The basic premise is that certain types of
organisms occur and thrive within a limited
range of conditions. When the conditions
change, so does the number and
distribution of organisms.
Macroinvertebrates
• Used to indicate water quality because:
 Found in almost all ecosystems and easy to
identify
 Organisms have limited mobility
 Sensitive to change
• Biotic Index to determine stream quality
Humans and Species
Extinction
• Experts estimate that up to 50,000 species
are becoming extinct each year.
• 10,000 times faster than the “normal” or
“natural” rate.
• Major cause: habitat loss
Habitat loss in PA
• Common causes:

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
Sprawl
Pollution
Logging
Mining
Forest fire suppression
Sprawl
• Urban sprawl is unplanned development
that results in more and more suburbs.
• Contributes significantly to water and air
pollution
• In Philly, 1 acre of open space/hour is
currently being developed
Pollution
• Results in habitat loss
• Affects organisms
directly (DDT)
Logging & Mining
• Destroyed habitats
• Polluted ecosystems with sediment, soil,
AMD
Fire Suppression
• The ecological succession of many pine
forests depends on naturally occurring
forest fires
• Leave native plants vulnerable to
competitors, because they grow faster but
would not adapt as fast as natives to fire
Passenger Pigeon
• Once abundant in
•
Northern PA became
extinct due to habitat
loss, over-hunting,
agriculture,
development and
industry.
Last pigeon died in
1914 in a zoo in Ohio