J. V. Siry, Ph.D.

The Imperiled Planet

The Dominant Animal: Chapter 10, Ecosystems and Human Domination

an on line guide

Jared Diamond, Collapse.



















Case Study




The Rialto in Venice over the Grand Canal.

"The evil that men do lives after them, the good oft interred with their bones."

Marc Antony, Funeral Oration, Shakespeare Julius Caesar

"Human beings and the natural world are on a collision course.... inflicting often irreversible damage on the environment and critical resources."

World Scientists Warning, 1992


"...vegetation is continuously undergoing various kinds of change."

Arthur Tansley, p. 193.

"The classification of vegetation and the concept of development."
AG Tansley - The Journal of Ecology, 1920

One-sided ways of considering and classifying vegetation result from differences of
training and interest and from the geographical isolation of different workers. Floristics, life-form, and habitat are all essential objects of synecological study.


Opening arguments (193-196)

a.    Ecosystem concept (review)  Tansley - eco-energetic

b.   Climax communities and perpetual change (succession) 

c.    The earth's life support systems

Ecosystem goods and ecosystem services (196-199)

                                               i.     Soil erosion

                                             ii.     deforestation                                            

                                             iii. medicines

Eight kinds of services:


generation of soils

ocean flood protection

natural pest control (also fertilization)

ameliorates weather

cycling of nutrients and waste disposal

pollination of plants

provisions tranquility & entertainment


The state of ecosystem services (203-205)

The three horseman of environmental impact (205-206)

                               summarized in the I = PAT identity.’

                              Formula is Population times Affluence (wealth) times Technology


Which is the most incisive description of impact? (204-205)

• The supply of certain ecosystem services has increased at the expense of others.

• Fish cannot continue to be harvested from wild populations at the present rate.

• The supply of fresh water to people is already inadequate to meet human and ecosystem needs in large areas of the world. . . ."

• Declining trends in the capacity of ecosystems to render pollutants harmless, keep nutrient levels in balance, give protection. . . ."



The three horseman of environmental impact (205)


The magnitude of the effects of human activities on our life support systems and the services and goods they can supply can be visualized as the product of three factors ...."


                               summarized in the I = PAT identity.’


                              Formula is Population times Affluence (wealth) times Technology


"Affluence in this context is simply per capita consumption."



"The population problem in the United States was more severe than that in many 'overpopulated' poor nations because of the high level of affluence and wasteful consumption in the US."







  1. Energy and matter can neither be created nor destroyed, merely altered.
  2. People inhabit places and alter the land, air, and water they depend upon.
  3. Disturbance must have an investment in nature commensurate with the quantity, quality, timing and distribution of the degradation.
  4. Nature bats last.

Trees in a forest.

The Ehrlichs' complete summation to their book.


Nourish the Earth, or perish.

Land is an essential source and stock of renewable resources


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