History of Ecology

1
History of Ecological Ideas
2
Introduction

• Although the real explosion in ecological studies
  did not take place until the 1960's, ecological
  thought goes back to the ancients
• Buffon and Linnaeus also played a role
  influencing the great explorers of the eighteenth
  and nineteenth centuries. For these explorers
  the ultimate goal was no longer just to collect
  and describe species, but to understand the
  interaction of organisms with their environment

3
Alexander von Humboldt(German, 1769-1859)

• From a well-to-do family
• Traveled extensively throughout Europe, America,
  and Russia
• Had a holistic view of nature

4
(No Transcript)
5
(No Transcript)
6
Ernst Haeckel (German, 1834-1919)

• He was the leading German disciple of Charles
  Darwin
• He coined the term Ecology
• He originally used the Greek spelling Oecologie,
  and defined it as the science of the relations
  of living organisms to the external world, their
  habitat, customs, energies, parasites, etc.

7

• Haeckel derived the new label from the same root
  found in the older word economy (Oekonomie)
  the Greek oikos, referring originally to the
  family household and its daily operations and
  maintenance
• The reason was that at that time, people thought
  that national economic affairs could be
  understood as an extension of the housekeepers
  budget. Haeckel thought that the Earth
  constituted a single economic unit

8

• From the beginning there was a strong Darwinian
  sense in ecology. Haeckel said in 1869 that
  ecology was the body of knowledge concerning the
  economy of nature (...) the study of all those
  complex interrelations referred to by Darwin as
  the condition of the struggle for the existence
• For many years the term was ignored. The use the
  economy of nature instead as in previous
  centuries natural economy, was used to refer to
  physiology

9

• The people working on the subject had little
  contact with each other. Although literally
  thousands of papers were published in those
  decades dealing with the number of species and
  individuals within a certain measured area and
  hundreds of new terms were proposed, ecology
  remained a rather static and descriptive science
• The term was retaken initially as oecology and
  then with its modern spelling ecology after the
  International Botanical Congress of 1893

10
Major Revolutions in the Ecological Thought

• Three major events revitalized the field
• a) The calculations of Lotka-Volterra cycle of
  population changes due to the predator-prey
  relations, as well as growth, decline, and cycle
  of populations
• b) Emphasis on competition the principle of
  competitive exclusion and its experimental
  testing by Gause
• c) Attention to energy turnover problems,
  particularly in freshwater and in the ocean

11
Biogeography

• The ancients (Hippocrates, Aristotle,
  Theophrastus, and others) had written about
  regional differences in the distribution of
  animals and plants and ascribed the differences
  to climatic factors
• They tried to explain the facts that there were
  elephants in Africa and Asia but not in between
  to the facts of former connections

12

• The imposition of the literal interpretation of
  the Bible in western thought created major
  problems
• The idea was that all plants and animals
  originated in the Garden of Eden, after the Flood
  they had been rescued in Noahs Ark from which
  they had dispersed again supposedly from Mount
  Ararat
• This interpretation, however, accepted the fact
  that species were not fixed in space but that
  they had to disperse and migrate

13

• The discovery of America and the fact that the
  fauna there was radically different than that of
  the Old World, created great consternation
• The creation of a single fauna and flora from a
  center of creation seemed more and more an
  impossibility

14

• The botanist Johann G. Gmelin (German,
  (1748-1804) was the first, in 1747, in proposing
  multiple centers of creations
• But the one who really pushed forward this
  concept was Georges Louis Leclerc Comte de Buffon
  (French, 1707-1788)

15

• He antagonized Linnaeus by saying that faunas (a
  practical geographical classification) and rather
  than shared characters had to be the basis for
  classification

16

• Buffon postulated that when the Earth cooled off,
  life was created in the far north because the
  tropical regions were still too hot for
  sustaining life. The earth makes the plants
  the earth and the plants make the animals
• Still, he could not explain why the tropical
  faunas of Africa and America, for example, were
  so different

17

• The first researchers interested in ecology were
  geographers. This was a very prominent discipline
  in the 19th. century. The world was still being
  mapped
• Two schools appeared
• a) biogeographers distribution of species around
  the world (the controlling interest was taxonomic
  rather than ecological)
• b) physiognomists (ecological geographers)
  they talked about vegetation rather than flora,
  for example

18

• For the latter, three principles dominated the
  new science
• a) classification of plants by their adaptive
  forms or structure rather than by their taxonomy
• b) emphasis on plants as social beings forming
  integrated societies
• c) identification of climate as the crucial
  determinant of both individual life forms and the
  communal pattern

19

• This is in accordance with the teaching of Buffon
  and, particularly, Alexander von Humboldt
• The latter had given the notion of isotherms
  (e.g., in the Andes)

20

• In the U.S., the first to apply this system was
  C. Hart Merriam, an ornithologist
• He developed the concept of life zones.

21

• In Europe it was Oscar Drude, Andreas Schimper,
  and Eugenius Warming
• The latter introduced the concept of plant
  communities and a great deal of the
  biogeographical terminology still employed today
• He tried to define the borderland where ecology
  meets physiology and morphology

22

• The latter part of the 19th. century produces
  terms such as mutualism, comensalism,
  symbiosis, succession, climax as well as a
  system of classification for plants communities
  such as hydrophytes, xerophytes,
  mesophytes, etc.
• The beginning of the 20th. century begins with
  the development of autoecology the
  environmental physiology of an individual
  organism and also the first look by zoologists to
  this new science
• For many years, until the 60's there was still
  talk of plant ecology and animal ecology as
  separate entities

23
The Darwinian Revolution

• On Darwins diary of the voyage of the Beagle, as
  well as in his Origin and autobiography, he
  mentioned again and again the importance of the
  knowledge of the distribution of species to
  understand their origin
• He was particularly struck by two facts
• a) The species of the temperate zones of South
  America were closely related to the ones in the
  tropical areas of that continent rather to the
  ones of the temperate zones of North America
• b) That fauna of islands were closely related to
  those of their closest continent

24

• For him, thus, distribution was not random. The
  question was what factors influence the
  introduction of species in a particular area?
• He is considered to be the father of zoogeography
  although Wallace also made important
  contributions
• A radical departure from Linnaeus who believed
  that all plants derived from a mountainous
  tropical island (Eden?) from which all spread all
  over the world

25

• Darwin opposed these ideas and so did Wallace.
  For them continents were static and animals did
  have a great ability to disperse

26

• Alphonse de Candolle proposed (1855) 20 botanical
  regions (centers of creations)
• Louis Agassiz (1857) was a creationist for whom
  every unsolved biological mystery was the
  product of the hand of God. However, his Ice
  Age Theory laid the bases for explanations
  related to the changing earth
• Darwins writings would break the non natural
  explanations for the origin and distribution of
  animals and plants. For him dispersal was due to
  two factors the ability to get to a new
  locations and the ability to colonize it

27
The Land Bridge Idea

• Darwins ideas, however, did not seem able to
  explain the discontinuities in distribution
  patterns in particular. To solve this problem
  numerous scientists proposed the idea of
  connections by land bridges. These researchers
  had two things in common low opinion of the
  dispersal abilities of animals (particularly
  mammals) and total disregard of the geological
  evidence

28

• The real questions came from astonishing facts
  beavers in Eurasia and America, same plants in
  the Pyrenees and in the Alps, mountains of
  Scandinavia and islands of the Arctic lowlands
  without anything in between and European plants
  in Tierra de Fuego, the strangeness of Australian
  biota (disjunct distributions)
• This became one of the major issues of
  biogeography during the first half of the 19th.
  century

29

• E. A. W. Zimmermann (1778-1783) proposed that the
  distribution of mammals can not be sufficiently
  explained by climate and rather it had to be
  explained by the history of earth. He proposed
  the land bridges theory to explain why continents
  and islands share the same fauna is because of
  former connections between then (land bridges).
  He is considered the father of historical
  biogeography.

30

• In 1922 E. R. Dunn proposed a causal analysis of
  faunas. The main tool of this school was the
  idea of land bridges
• These ideas were championed by the American
  mammalogist G. G. Simpson by saying that there
  are different kinds of bridges connecting land
  masses

31
(No Transcript)
32
(No Transcript)
33
(No Transcript)
34
(No Transcript)
35
(No Transcript)
36

• The third school came from Alfred Wegeners
  publication in 1915 of the continental drift
  theory
• Original discounted because of the lack of a
  mechanical explanation for it
• This did not see a revival until the 1960's when
  the mechanisms of plate tectonics became
  apparent. This changed everything

37
(No Transcript)
38
(No Transcript)