Introduction
3 IMPORTANT MAXIMS
- IMMENSITY OF GEOLOGIC TIME
- Importance of Rates of Change
- NOTHING IS PERMANENT EXCEPT CHANGE
- Irreversible Cumulative Change
- ECOLOGIC INTERACTION BETWEEN LIVING AND NON-LIVING REALMS
- WITH REGARD TO THE EVOLUTION OF THE EARTH:
- Until 1700's - Earth created ~4000 BC
- TIME SHORT; NO EVOLUTION - EVERYTHING IS FIXED
- Now - Earth formed ~4.5 billion years ago
- TIME LONG; EARTH HAS DIFFERENTIATED & EVOLVED
- Various compositional layers - Core, Mantle, Crust, Ocean, Atmosphere
- have formed
- These layers have changed with time
- LIFE HAS EVOLVED & INTERACTED WITH NON-LIVING EARTH
- Atmosphere has become oxygen rich from photosynthetically released
oxygen (& the ozone layer has formed)
- Carbon and Nitrogen cycle through the crust and biosphere
- Organisms have colonized the land
HUMANS' PLACE IN THE GLOBAL ECOSYSTEM
- AT LEAST 2 VIEWS
- Integral Part - "Primitive"
- Master of the Environment - Stewart or Caretaker
- ENVIRONMENT IS A COMMODITY
- BETWEEN 1600 & 1950 EXTINCTIONS AMONG VERTEBRATES ALONE WERE 64
MAMMAL (1.56%), 109 BIRD (1.27%), 20 REPTILE (0.3%), & 33 AMPHIBIAN
(1.26%) SPECIES
- This is a tremendous loss of biodiversity, & at these rates, all
vertebrate species will be extinct in 13,330 years
- However, extinction rates are increasing exponentially [for birds -
0.12% per 100 yrs during 17th & 18th Centuries; 0.5% per 100 years
during the 19th Century, and 0.8% per 100 years in the first half of the
20th Century], and a human-induced MASS EXTINCTION may have resulted by
the end of the 21st Century.
- SINCE 1775, MORE THAN 500 SPECIES OF PLANTS AND ANIMALS ON THE NORTH
AMERICAN HAVE GONE EXTINCT
- WE ARE WOEFULLY IGNORANT OF EXTINCTIONS AMONG INVERTEBRATE ANIMALS
IN THE LAST SEVERAL CENTURIES
- EXTINCTION CAUSED BY OUTRIGHT KILLING OF ORGANISMS & HABITAT DESTRUCTION
- FOULING THE GLOBAL "NEST"
- Water Pollution
- RAW SEWAGE; DDT & OTHER PESTICIDES; FERTILIZERS; DETERGENTS; NUCLEAR
WASTES
- Atmospheric Pollution
- CO2 - GLOBAL WARMING; ACID RAIN; CHOLOROFLUOROCARBONS -
OZONE HOLE; NUCLEAR WASTES
- RESOURCE DEPLETION
- Water; Mineral resources; Fossil Fuels
- HUMAN OVERPOPULATION