1. ECOSYSTEMS OF THE BIOSPHERE

2. ECOSYSTEM

3. No true ecology prior to the Darwinian revolution; however, many strands of thought began to be formed before the science of ecology came into its own in the early 20th century. These were applied to the old discipline of Natural History, a major part of Aristotelian philosophy.

4. Carl von Linné (Carolus Linnaeus)
Provided a means to order the array of living things, thus providing the basis by which the diversity of life could be catalogued
Proposed that nature was in balance, an economy of nature
; Sweden

5. Voyages of Exploration
Friedrich Wilhelm Heinrich Alexander von Humboldt ( ) explored the Americas and stated principle of diversity gradient from the equator to the poles
Inspired explorations of Darwin, Wallace, Huxley, Haeckel and many others

6. Ernst Heinrich Philipp August Haeckel
Prolific writer and naturalist
Coined the term Ecology, which means the study of the house.
Haeckel ( , Germany) in the Canary Islands with his collecting assistant

7. Johannes Eugenius Bülow Warming
One of the founders of the science of ecology
Studied the ecology of plants in Denmark
Expeditions to Scandinavia, South America, and Western Europe
Beyond description he related how plants, though from different parts of the world and unrelated, solve environmental problems in similar ways.
; Denmark

8. Stephen Alfred Forbes Illinois Natural History Survey
The Lake as a Microcosm (1887)
One of the earliest ecosystem studies
The first indispensable requisite is a thorough knowledge of the natural order—an intelligently conducted natural history survey. Without the general knowledge which such a survey would give us, all our measures must be empirical, temporary, uncertain, and often dangerous (Forbes 1880).
, USA

9. Types of Succession
Primary
Secondary
Seasonal

11. Primary and Secondary Succession

12. Cowles, Clements, and Gleason
Henry Chandler Cowles ( , USA) built on Warming’s work and studied succession of vegetation on dunes of Lake Michigan
Frederic Edward Clements ( , USA) worked on prairie grasslands and thought of communities as living entities that return in a predictable, deterministic way through succession (theory held sway until 1960’s)
Henry Allan Gleason ( , USA) challenged deterministic approach and suggested that succession was the collective change by all individual species and, therefore, not predictable

13. Charles Sutherland Elton
Founded areas of Population and Community ecology
Modern concept of the food web
; Britain

14. FOOD WEBS

15. Law of Tolerance
Justus von Leibig ( , Germany) and Law of the Minimum
Victor Ernest Shelford ( , USA) and Law of Tolerance
Worked with Cowles and became president of Illinois Natural History Survey, the first president of the Ecological Society of America, and a founder of the Nature Conservancy (because the ESA refused to take a political stance regarding conservation)

16. Vladimir Ivanovich Vernadsky
Founder of biogeochemistry
Began to look at the world as a living system in which elements were cycled
Ecology is the science of the biosphere
Though term had been coined by Eduard Suess ( , Austria) in 1875 (the place where life dwells), Vernadsky gave it the modern meaning in 1926
, Ukraine and USSR

17. George Evelyn Hutchinson
Zoologist who became interested in biogeochemistry of lakes
Discovered Vernadsky and extended work of Forbes
Place of each living thing in its ecological setting
Taught at Yale for 43 years without Ph.D.
Provided theoretical foundation for aquatic ecology
Defined niche concept
; Britain and USA

18. Raymond Laurel Lindeman
Post doctoral student of Hutchinson
Defined 10% Law for food pyramid in Cedar Creek Ecosystem in Minnesota
, USA

19. The Brothers Odum
Howard Thomas Odum ( ; known as H.T.) was a student of G.E. Hutchinson
One of the founders of systems ecology
Together with his older brother, Eugene Pleasants Odum ( ), who was a student of V. E. Shelford, modeled an ecosystem as energy flow through a system.

20. ENERGY FLOW IN THE ECOSYSTEM
Ecosystem, a term coined by Arthur George Tansley ( , Britain) in 1935.
Though the organisms may claim our prime interest, when we are trying to think fundamentally, we cannot separate them from their special environments, with which they form one physical system.

21. Biomes
Concept pioneered by Shelford and Clements and modified by ecosystem paradigm