Subodh Sharma Dr.nat.tech.; Aquatic Ecology Centre, P.O. Box: 6250, sharmaku@yahoo.com. 1

1 hr.Unit 1.1Introduction to ecology and environment

PG diploma in Environment Education program

Supported by NORAD

Subodh Sharma Dr.nat.tech.; Aquatic Ecology Centre, P.O. Box: 6250, sharmaku@yahoo.com. 2

What is ecology?

Definition of Ecology- the scientific study of interactions between organisms and their environments, focusing on energy transfer

It is a science of relationships between living organisms and their environment

Subodh Sharma Dr.nat.tech.; Aquatic Ecology Centre, P.O. Box: 6250, sharmaku@yahoo.com. 3

What is ecology?

The word “ecology” was first proposed by the German biologist Ernst Haeckel in 1869

It is derived from the Greek

Environmental sciences is an area of modern ecology

Subodh Sharma Dr.nat.tech.; Aquatic Ecology Centre, P.O. Box: 6250, sharmaku@yahoo.com. 4

History of ecology?

Alexander von Humboldt, often considered the true father of ecology, reported impressive number of species in his book titled “Idea for a Plant Geography” published in 1805.

In 1850, Charles Darwin published “On the Origin of Species By Means of Natural Selection”.

By the 19th century, Lavoisier and de Saussure discovered nitrogen cycle.

Austrian Geologist Eduard Suess proposed the term “biosphere” in 1875.

In 1920, Vladimir I. Vernadsky described the principles of the biogeochemical cycles.

Subodh Sharma Dr.nat.tech.; Aquatic Ecology Centre, P.O. Box: 6250, sharmaku@yahoo.com. 5

History of ecology?

It was in 1935 that Arthur Tansley coined the term ecosystem.Human ecology began in the 1920s.Ecology became a central part of the World’s politics as early as

1971.In 1972, the UN held the first international conference in the

human environment in Stockholm.In 1992, Earth Summit was held in Rio de Janeiro.In 1997, the dangers biosphere is facing was realized from an

international conference leading to the Kyoto Protocol.

In Kyoto, most of the world’s nations recognized the importance of looking at ecology from a global point of view. On a worldwide scale, and to take into account the impact of humans on the Earth’s environment

Subodh Sharma Dr.nat.tech.; Aquatic Ecology Centre, P.O. Box: 6250, sharmaku@yahoo.com. 6

The environment is made up of two factors:

Biotic factors- all living organisms inhabiting the Earth

Abiotic factors- nonliving parts of the environment (i.e. temperature, soil, light, moisture, air currents)

What do you mean by environment?

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Scope and relevance of ecology…

Ecology is a basic division of biology

It is an integral part of any and all of the taxonomic divisions

Source: Fig. 1.1 Odum, 1971

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Levels of OrganizationBest way to delimit modern ecology is to consider it in terms of the concepts of level of organization (Odum, 1971)

Diagram Showing Ecological Organization From Odum (1971)

Genes Cells Organs OrganismsPopula-tions

Commun-ities

BIOTICCOMPONENTS

Plus

ABIOTICCOMPONENTS

Equals

BIOSYSTEMS Genetic Systems

CellSystems

OrganSystems

OrganismicSystems

PopulationSystems

Ecosystems

Matter Energy

Subodh Sharma Dr.nat.tech.; Aquatic Ecology Centre, P.O. Box: 6250, sharmaku@yahoo.com. 9

Levels of Organization

Organism

Population

Community

Biosphere

Ecosystem

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Levels of Organization

Organism- any unicellular or multicellular form exhibiting all of the characteristics of life, an individual.

•The lowest level of organization

Subodh Sharma Dr.nat.tech.; Aquatic Ecology Centre, P.O. Box: 6250, sharmaku@yahoo.com. 11

Levels of Organization

Population-a group of organisms of one species living in the same place at the same time that interbreed and compete with each other for resources (ex. food, mates, shelter)

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Levels of Organization

Community- several interacting populations that inhabit a common environment and are interdependent.

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Levels of Organization

Ecosystem- populations in a community and the abiotic factors with which they interact (ex. marine, terrestrial)

Subodh Sharma Dr.nat.tech.; Aquatic Ecology Centre, P.O. Box: 6250, sharmaku@yahoo.com. 14

Levels of Organization

Biosphere- life supporting portions of Earth composed of air, land, fresh water, and salt water.

•The highest level of organization