Ecology: Study / Science of Biosphere

Ecology: Study / Science of Biosphere

Ecology: Concepts & Facts

• The term ecology is the combination of two Greek words, oikos (='house/habitat/dwelling place) and logos (= the study/science of). Thus, Ecology is the study/science of the biosphere (dwelling place of organism)

• Ecology is defined as the study of the relationships of organisms to one another and to their physical environment. Ecology is also called bioecology, bionomics, or environmental biology.

• There is some controversy about the person who coined the term 'ecology.' Some scholars think that it was H. Reiter who introduced the term 'Oekologie' (ecology) in 1868, but most of the scholars think that it was German scientist Ernst Hackel (1834-1919) who coined the term Oekologie' (ecology) and put the first precise definition and explanation in the year 1869.

American biologist E.P. Odum (1913-2002) wrote in his popular textbook 'Fundamentals of Ecology': "The word 'oekologie' was first proposed by Ernst Haeckel in 1869.

Haeckel defined ecology as 'the study of the natural environment, including the relations of organisms to one another and to their surroundings." Ernst Hackel (1834-1919) is known as the father of ecology (classical period).

According to some scholars, German naturalist Alexander Von Humboldt (1769–1859) is the father of ecology (classical period). 

• E.P. Odum (1913-2002) is known as the father of modern ecology (modern period).

• Ramdeo Misra (1908-98) is revered as the father of Indian ecology.

Note: In science, the period from the beginning to the 19th century (i.e., the beginning century) is considered the 'Classical Period,' and the period from century to the present (i.e., 1901 to the present) as 'Modern Period.'

Like other fields of learning, the development in the field of ecology has been gradual. Ecology has progressed from natural history and biogeography to ecosystem ecology.

In the last quarter of the 20th century (i.e., 1975-2000), global ecology, with an emphasis on biodiversity, climate change, and ecological sustainability, emerged. Global ecology is a subfield of ecology, and it treats ecology at a global scale.

Levels of Ecological Organisation (Ecological Hierarchy)

Levels of ecological organization, or ecological hierarchy, provide a convenient but holistic approach to understanding ecology, which is very complex in nature. It is represented in triangular form in the diagram below.

In ecology, levels of ecological/biospherical organization range from organism to ecosphere/biosphere. It is also called Ecological/Biospherical Hierarchy (hierarchy means an arrangement into a graded series).

Levels of ecological organization, i.e., ecological hierarchy, and seven transcending processes or functions are depicted as vertical components in descending order.

Levels of Ecological Organisation (Ecological Hierarchy)

The levels of ecological organisation

1. Organism:

The organism is the basic and smallest unit to study in ecology. Organism means any individual living being/thing, whether plant or animal. Thus, any living structure (plant, animal, bacterium, or fungus) capable of growth and reproduction is called an organism.

(Note: Viruses are not included in constituent parts of organisms because they are incapable of autonomous metabolism, growth, or reproduction.)

2. Population

The term population, originally coined to denote a group of people, is broadened to include groups of individuals of any kind of organism. Hence, a population is a group of individuals of a plant or animal species inhabiting a given area. For example all individuals of roses in a area, all individuals of elephants in a area etc.

3. Community:

The term community is a combination of the French word commune (a group of people) and the noun suffix "-ity (= state, condition).

Community (sometimes designated as biotic community) is an assemblage of all the populations occupying a given area. For example: all population of roses in a area, all population of elephants in a area etc.

4. Ecosystem:

Ecosystem is the acronym of ecological system. The system means a set of things that work together. The biological community and the physical environment function together as an ecological system, or ecosystem.

It is a fundamental functional unit of ecology because it includes both biotic (living) and abiotic (non-living) environments. 

For example: Forest, grassland, desert, marine, lake, river, pond, crop field, park, spacecraft, swimming pool, well, aquarium, etc.

Ecosystem is not only a middle level but also a very important level of ecological hierarchy. So the structure and functioning of the ecosystem shall be discussed in detail in 'Biosphere: A Giant Ecosystem.'

5. Landscape:

The term landscape, originally referring to a painting and explained as 'an expanse of scenery seen by the eye as one view,"

In ecology, landscape is defined as a heterogeneous area composed of a cluster of interacting ecosystems that are repeated in a similar manner throughout. For example: a watershed, etc.

6. Biome:

The term biome is a combination of the Greek word bios (life) and the noun suffix "-(o)ma" (mass, growth). A biome is a large regional unit characterized by a major vegetation type and associated fauna found in a specific climate zone.

For example:

(a) Terrestrial (land-related) Biomes— Equatorial (0°-15° of globe) evergreen forest biome, Tropical (12°–25°) rainforest biome, Temperate (45°–66.5°)¹ deciduous forest biome etc.

(b) Aquatic (water-related) Biomes — Marine (salty-water) biomes like oceans, seas, etc. Freshwater biomes are lentic (standing water): lakes and ponds & lotic (running water): rivers and streams & wetlands: marshes and swamp forests (like mangrove forests).

7. Ecosphere/Biosphere:

The largest and most nearly self-sufficient ecological/biological system is designated as the ecosphere/biosphere.  The ecosphere/biosphere includes all the living organisms interacting with the physical environment as a whole to maintain a self-adjusting, loosely controlled, pulsating state.

Note: A simple formula to remember levels of ecological organization (ecological hierarchy):