J. V. Siry, Ph.D.

The Imperiled Planet

The Dominant Animal: Chapter 9, Cycles of Life: ecology and biology

an on line guide

Lynne Margulis, Symbiotic Planet, & Early Life.




















Learning from natural relations of the ecology and evolution of life. spectacles

When coupled, evolution and ecology provide a binocular view of how life adapts over time.

Binocular vision means a depth of field is possible.

Background | Outline | Argument | Evidence | Conclusions


The cycles of life, death, renewal & the re-creation of biocommunities.

Defining ecology: it's a problem.

Ecology is the study of the functions of living populations in the communities where they thrive and in which they are nourished.


Energy conversion in the form of food webs & the cycling of nutrients control growth.

outline | argument | summary


  1. Evidence
    1. dialectical analysis applied
    2. matrix reveals
    3. six conditions of existence
  2. Summary
    1. What limits human growth
    2. The concepts of optimal conditions, optimality, and stability

      Stewardship matters.

      Background | Outline | Argument | Evidence | Conclusions


      Try taking next steps.

Stewarding the land, air, and water as the basis of life.

E. O. Wilson Edward O. Wilson. degrading

Defining ecology.

  1. simple: the scientific study of an organism or species in its surroundings. [what a species is? breeding populations? other.]
  2. complex: Ecology is the systemic science of the functional and fundamental relations among living organisms and the recycling nutrients needed for their reproductive success in the environment, milieu, or surrounding conditions of material existence on which they all depend.

laws | niche | trophic webs

Three laws of ecology dictate all life:

I To every action there is always an equal & opposite reaction.

II Whatever amount you start out with you end up with.

III Everything costs something.

Niche, three varieties, or ways to measure any creatures needs:

One is "spacetime address," range and life cycle.

Two is occupation, or means of acquiring a living.

Three is energy utilization over time in a place.

Trophic levels, mean that an organisms feeding behavior places a creature in certain observable and measurable levels in a food web based on the criteria of how they either make their own food or feed off of other levels:

Trophic pyramid
top level predator
carnivore consumers
omnivore consumers


Background | Outline | Argument | Evidence | Conclusions


There are powerful elements, forces, and factors unseen and understood as universal in our experience of nature:

"Nature is more complicated than we can think."

J. B. S. Haldane, evolutionary biologist.

"Nature bats last."

Because of the Four Fundamental Forces:
     Gravity is the latent force of matter that holds the stars and planets together.
     Weak nuclear interaction is 1025 times stronger than gravity accounts for radiation.
     Electromagnetic is 1036 times stronger than gravity holds atoms together.
     Strong Nuclear is 1038 times stronger than gravity holds atomic nuclei together.

When these forces were discovered.

The game of life

Background | Outline | Argument | Evidence | Conclusions


Six points emerge after dialectically analyzing nature

By dividing nature in two and then into two again we see the complexity emerge when we put the pieces back together:

The dialectical matrix of ecological science:
Four divisions 3. evolutionary 4. ecological
1. inorganic oxygen iron & Ca
2. organic five kingdoms 20 food crops

§ Biocenose is an association of different organisms forming a closely integrated community.

Six points:

1) Take a deep breath and hold you breath." We are co-conspiring.
2) habitats as the inorganic conditions (light, air, slope, temperature, elements, compounds, pH, water.)
3) biotic communities as the organic conditions (bacteria, vegetation, fungi, animals, parasites.)

4) Eutrophy & oligotrophy are divergent levels of nourishment-nutrient cycles
5) Synergy how the whole system is greater than the mere sum of the working parts.
6) biosphere as the totality of life on the planet in its systemic relations.

Background | Outline | Argument | Evidence | Conclusions


"…human beings are unlikely to be capable of assembling reasonably stable large-scale ecosystems"

We are instead an edge species (savannas, farms, woodland)

We thrive in disturbance and disturb large ecosystems with agricultural, mining, residences, and industrial facilities.

Duration of human disturbance is essentially a limitation.

limits of human dominance / disturbance are both:
A) carrying capacity density
B) assimilative capacity intensity
quality, timing or frequency, & distribution.

Optimum–where too little and too much hinder growth.

The status of–or most favorable condition for– is optimality.

There is a range withing which all creatures thrive; so too the recovery time necessary to re-establish an optimal status.

Background | Outline | Argument | Evidence | Conclusions


Sources authors concepts
books stacked

Miller, environ. science

Colinvaux, niche

Bateson, geometry

Krebs, 10 commandments

Margulis, eukaryots cells

Lovelock, gaia




opening book

Background | Outline | Argument | Evidence | Conclusions

Mayr | Thomas | Wilson | Hardin | Darwin | Margulis | Steingraber | Carr | Keller | Watson



Readings | Vocabulary | Description | Overview | Assignments | Lectures | Index of this course | Grades

technology index learn science index learn gene index learn social science index learn photograph index learn Darwin Index