Barry Commoner was an American biologist and environmentalist who is credited as a founder of the modern environmental movement. He was famous for his public campaigns against nuclear testing, chemical pollution, and environmental decay. Commoner summarized the basic principles of ecology into what he termed the "Four Laws of Ecology": 1) Everything is connected to everything else, 2) There is strength and stability in the unity of differences, 3) Consumption must not exceed production, and 4) Everything has a purpose. These laws explain the relationships and interdependencies found in communities and ecosystems and that humankind is dependent on the characteristics of the land.

1. “LAWS
OF
ECOLOGY”

2. “We travel together, passengers on a little
spaceship, dependent on vulnerable supplies
of air, water, and soil, all committed for our
safetytoitssecurityandpeace:preservedfrom
annihilation only by the care, the work, and I
willsaythelove,wegiveourfragilecraft.”
-- Adlai Stevenson

3. BARRY COMMONER
 “a leader among a generation of scientist-
activists” (New York Times) and possibly
“the greatest environmentalist of the 20th
century” (Ralph Nader), died in New York on
September 30, aged 95
Credited as a founder of the modern
environmental movement
 Commoner was among the world’s best
known ecologists in the 1960s, 70s and 80s.
 He was famous for his public campaigns
against nuclear testing, chemical pollution
and environmental decay
In the early 1970s, he wrote “The closing
circle”, in w/c he discussed the rapid growth
of industry & technology & their persistent
effect on all forms of life.

4.  He suggested that we can reduce the
negative effects by sensitizing, informing &
educating ourselves about our connection
to the natural world.
 He summarized the basic of ecology into
what he termed “laws of ecology”. Others
have also used this idea to develop simple
statements that help us understand &
remember our connections to nature.
 He was best known for his “Four (4) Laws
of Ecology”
BARRY COMMONER

5. FOUR (4) LAWS OF ECOLOGY:
1. Everything is connected to everything else
 Being connected is seen not only in the relationship among the
organisms but also in the relationship of organisms with physical
factors.
2. There is strength & stability in the Unity of Differences
 The ecosystem has different components, and each is needed for the
ecosystem to function.
3. Consumption must not exceed production
 Any ecosystem has the capacity to sustain life. This is called its carrying
capacity.
4. Everything has a Purpose
 Each of us has a role to perform & responsibility to protect the
environment.

6. These laws form the basis for studying and understanding the relationships and interdependencies
found in communities and ecosystems. They further explain that humankind is, in fact, only one
member of the biotic community and that people are shaped and nurtured by the characteristics of
the land.