A. The word ecology comes from the Greek oikos, meaning house or home
B. Ecology = the systematic study of how organisms interact with one
another and with their environment
1. The environment consists of both a living component, the biotic
environment (other organisms) and a non-living component, the abiotic
environment, e.g. physical factors such as soil, rainfall, sunlight,
temperatures
C. Levels of ecological organization:
1. Population - group of individuals of the same species occupying
a common geographical area
2. Community - two or more populations of different species
occupying the same geographical area. Populations and communities include
only biotic factors
3. Ecosystem - a community plus its abiotic factors, e.g. soil,
rain, temperatures, etc. Ecosystems are further influenced by global
phenomena such as climate patterns, nutrient cycles, etc. All the ecosystems
on earth make up the:
4. Biosphere - the portion of the earth that contains living
species. It includes the atmosphere, oceans, soils and the physical and
biological cycles that affect them
D. Ecology is an extremely complex and very diverse subject and it includes
a variety of disciplines in addition to biology, e.g. geology, chemistry,
physics, meteorology, and mathematics
A. The radicalism of the 1960's, coupled with concerns about a
deteriorating environment and the publication of two influential books brought
the science of ecology into the popular culture:
1. Rachael Carson - "Silent
Spring" awoke the general public and made them aware of the dangers
of pollution and environmental degradation. She envisioned a "silent
spring" sometime in the near future because all the song birds might
eventually become extinct due to the use of pesticides
a. American Bald Eagle nearly went extinct due to the pesticide DDT
2. Paul Ehrlich - "Population Bomb" said much the same
as Essay on the Principle of Population written by Malthus 200 hundred years
earlier. Both argued that the earth could support only so many people
and that population growth should be slowed. Ehrlich founded the
organization Zero Population Growth, which recently changed its name to Population
Connection
A. Early 1900's well-meaning nature lovers introduced deer to Angel Island,
in San Francisco Bay
B. With no natural predators controls and people feeding them, the
population quickly rose to a level much higher (300) than the island could
support
C. As the deer began to starve they ate most of the native vegetation.
Without vegetation the soil started washing away and the island environment
rapidly deteriorated
D. Proposal to thin the herd by hunting or introducing natural predators
were considered too cruel
E. Two thirds of the population was rounded up and moved to the mainland,
at a cost of $3,000 per deer
F. Within 60 days the majority of the deer were killed by cars, dogs,
coyotes and hunters
G. Angel Island illustrates a basic ecological principle: a population's
growth is dependent on the resources of its environment. Human
intervention can only postpone, not prevent the inevitable