21 Ecosystems What They Are

7/25/2019 21 Ecosystems What They Are

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Subodh Sharma Dr.nat.tech.; Aquatic Ecology Centre, P.O. Box: 6250, [email protected].

Unit 2.1.(45 min)

2.1 Ecosystems: What they are,how they Work, and how they

Change?

PG diploma in Environment Education program


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Ecosystem What They AreWhere did the concept come

from?

Sir Arthur Tansley, a Renaissance man

coined the concept in 1935

~ Karl Mobius (1877)

~ S. A. Forbes (1887)


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EcosystemsEugene Odum

~ Took concept of Ecosystem and

brought it to the attention of theecological community and made it

a fundamental idea in society


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EcosystemsEugene Odum cont

~1953 published classic

Fundamentals of Ecology


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EcosystemsEugene Odum

cont~ Figure 2.1

mixesbiological

systems with

physicalcomponents


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Ecosystems Eugene Odum cont

~ Faced

criticism

and

developed

Figure 2.2


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EcosystemsEugene Odum cont

~ Advocated using the idea of ecosystem

beyond simply biology to the socialsciences--New Ecology


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ECOLOGY :

interdisciplinary

science


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It overlaps with many elements of physical and

biological sciences

ECOLOGY

HYDROLOGYGENETICS

ATMOSPHERIC

STUDIES

GEOLOGY

BEHAVIOR

BIOCHEMISTRY

PHYSIOLOGY


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EcosystemsTHE RULES OF ECOLOGY

F. A. BAZZAZ:

1. Everything is connected to everything else.

2. Everything must go somewhere.

3. There is no such thing as a free lunch.


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ECO + SYSTEM

Part of word relates

to the environment

Collection of related parts

that function as a unit


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ECOSYSTEMDEFINITIONS


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Any area of nature that includes livingorganisms and non-living substancesthat interact to produce an exchange of

materials between the living and non-living parts is an ecological system orecosystem.

(E. P. Odum(1959) Fundamentals of Ecology W. B. Sanders,Philadelephia.)


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Due to that

definition


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2 basic ECOSYSTEM

components are :LIVING - components

( biotic )

PHYSICAL- components

( abiotic )


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Britannica def : the complex of living organisms,

their physical environment, and alltheir interrelationships in a particular

unit of space


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Examples of ecosystems


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also called Lo t i c Ec o s y s t em , any spring, stream,or river viewed as an ecological unit of the bioticcommunity and the physiochemical environment,within which mass and energy are exchanged.The waters are usually flowing (lotic) and exhibit

a longitudinal gradation in temperatures,concentration of dissolved material, turbidity, andatmospheric gases, from the source to themouth.

riverine ecosystems


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boundary ecosystemcomplex of living organisms in areas where

one body of water meets another, e.g.,estuaries and lagoons, or where a body ofwater meets the land, e.g., marshes. The

latter are often called wetlands.


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m a r i n e e co s y s t e m : complexof living

organisms in the ocean environment


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Lacustrine - Pertaining to lakes includes

wetlands and deepwater habitats that may

be tidal or non-tidal but ocean derived salinityis less than one part per thousand (1 ppt). 1

ppt is the equivalent of one gram of sodium

chloride (salt) per liter of water.

lacustrine ecosystem


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polar ecosystem : complex of livingorganisms in polar regions such as polarbarrens and tundra


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Summary The ecosystem is the central theme.

It is man the geological agent, not so much asman the animal, .

Nature with our intelligent help, can cope withmans physiological needs and wastes, but shehas no homeostatic mechanisms to cope withbulldozers, concrete, and the kind of agro-industrial air, water, and soil pollution that will be

hard to contain as long s the human populationitself remains out of control.

(Odum, 1971 page 36 First edition)

21 Ecosystems What They Are

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