How are environmental science and ecology related
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How are environmental science and ecology related

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How are environmental science and ecology related

Ecology is, literally, the study of where living organisms live. By contrast, Environmental Science is a broader, interdisciplinary field in which ecologists work with other physical, chemical, and biological “ologists” to study and seek solutions to environmental problems.

How are environmental science and ecology related

Ecology- Oikos + logos

Oikos means home/place

logos- study

The study of the relationship of living organisms with each other, as well as their environment, is called ecology.

History of Ecology-

  • Ancient texts like the Vedas, the Samhitas, the Brahmanas, and Aranyakas Upanishads consist of some ecological concepts.
  • Charaka-Samhita consists of information that air, land, water, and seasons are essential for life.


All living and nonliving things in short everything which affects an organism are collectively called environment.

  • all organisms obligatorily depend on another organism for food, energy, etc.
  • the environment consists of both biotic and abiotic factors

Example- Fish in a pond

External environment-

  • Abiotic Factors- light, temperature, water consisting of nutrients, oxygen, organic, and dissolved substances.
  • Biotic Factors- Microorganisms(planktons), aquatic plants, decomposers, and aquatic animals, etc.

Internal environment-

  • relatively stable as compared to the external environment.
  • injury, illness, or excessive stress affects the internal environment

INDIVIDUAL- they have the ability to function independently.

it may be a plant, animal, bacteria, algae, fungi, etc.

cell, tissue, organ, organ system all work together to carry out all processes of life


A group of organisms of either the same or different species which occupy a defined area at a specific time is called population.

Population growth-

 supporting factors- natality(birth rate) and immigration.

detrimental- mortality and emigration

Population Density-

the number of individuals of a population and area occupied by them


Each organism needs some other organisms for their survival with which they interact in different ways.

  • Plants are the only organisms that make their own food still they need pollinators(insects mainly) for pollination, decomposers, and also other microorganisms which can enhance their nutrient supply.
  • communities are mainly named after the dominant plant species. for eg-Grassland community-dominated by grasses but also consists of herbs,  shrubs, animals, etc.


  • the structural and functional unit of the biosphere.
  • It includes plants, trees, animals, fishes, birds, water, soil, people
  • large variations are seen in the size of the ecosystem. A small drop of water, as well as a large forest both, are an ecosystem.
  • if any part of the ecosystem is damaged it affects all the components of the ecosystem.
  • A healthy ecosystem stands for the situation when all elements are balanced and organisms reproduce themselves.

Abiotic Components-

  • It comprises inorganic and non-living parts.
  • also includes chemicals and physical processes like floods, climates, and weather conditions.
  • they are the most important determinants of where and how well an organism exists.
  • ENERGY- Sun is the most important source of energy on earth.

Animals are not capable of using the energy from the sun directly so they depend on plants or other animals or both.


Variation in temperature together with annual variation in precipitation (both rain and snow) account for the formation of major biomes

  • water is essential for all living beings, maximum biochemical reactions take place in aquatic medium.
  • water also regulates the body temperature.


It is the most ecologically relevant environmental factor.

significance of temperature-

  • temperature affects the kinetics of enzymes and through it the basal metabolism, activity and other physiological functions of the organism
  • distribution of living beings


A wide variety of organisms thrive inland like microbes, protozoa, fungi, invertebrates, etc.

organisms can be terrestrial or aquatic.

  • life exists in extreme and harsh habitats- scorching Rajasthan desert, rain-soaked Meghalaya forest, deep ocean trenches, boiling thermal springs, high mountain tops, etc.


proteins, carbohydrates, lipids, humic substances are formed on the decomposition of inorganic compounds.

they are required in different concentrations for different individuals and  essential for organisms to survive


It has a strong influence on areas temperature

for eg. Temperature decreases progressively from the equator towards the poles and from plains to mountain tops.

Biotic factors

They include living organisms.

they are classified according to their functional attributes.


All autotrophs of the ecosystem are producers.

  • producers absorb solar energy and convert it into chemical energy so also called transducers or converters
  • primary producers in an aquatic ecosystem are phytoplankton, algae, and higher plants.
  • In the terrestrial ecosystem, major producers are herbaceous and woody plants.
  • they synthesize carbohydrates from simple inorganic raw material in presence of sunlight by the process of photosynthesis.


they directly or indirectly depend on producers for food. They are incapable of producing their own food.

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Types of consumers-

Macro consumers:

feed on plants or animals or both and are categorized accordingly

primary consumer-herbivores eg. insect, bird, mammals, mollusks, plant parasites, etc

Secondary consumers- feed on the primary, fish, wolves, whales, animal parasites, etc

top consumers/carnivores feed on secondary consumers eg. lion, man, hawk, peacock, etc.

Omnivores-organisms which consume both plant and animals eg. man, peacock, cockroach, crow, etc.

Micro Consumers/decomposers/ saprotrophs-

organisms that decompose the dead body.

The main decomposers are- fungi and bacteria.

  • they play a significant role in the nutrient cycle
  • decomposers convert complex organic materials into simple organic materials through the process of decomposition.


  • Zone of junction between two or more diverse ecosystems.

for the eg-Mangrove forest is an ecotone between marine and terrestrial ecosystem.

grassland, estuary, riverbank, etc.

Characteristics of Ecotone-

  • It may be very narrow or wide
  • It has conditions intermediate to adjacent ecosystem so-called zone of tension.
  • there is a progressive increase in species of coming community and a decrease in species of the other outgoing community.
    • Edge effect- when the population density of some species is much greater in its zone than either community

    for eg- density of birds is greater in the mixed habitat of the ecotone between the forest and desert.

    NICHE- the unique functional role or place of species in an ecosystem.

    It describes all the physical, chemical, and biological factors that a species needs to survive, stay healthy, and reproduce 

No two species have exact identical niches.

to conserve any species in its native habitat one should have knowledge about its niche.

Types of Niche-

  1. Habitat niche- where it leaves
  2. food niche-eating habits and decomposers and species it competes with
  3. Reproductive niche- how and when it reproduces
  4. physical and chemical niche-temperature, humidity, and other requirements

The terrestrial part of the biosphere is divided into many biomes.

no two biomes are alike.

Terrestrial biomes-

  • TUNDRA-This biome is devoid of trees and also known as arctic desert or alpine tundra.

lichen, mosses, sedges, reindeer, arctic fox, polar bear, snowy owl, etc are seen.

reptiles and amphibians are almost absent.

  • TAIGA-dominating vegetation- coniferous evergreen

the fauna consists of birds, hawks, elks, puma, Siberian tiger, etc


  • flora-trees like beech, oak, maple, cherry
  • animals are familiar vertebrates and invertebrates.
  • they are the most productive agricultural areas of the earth
  • TROPICAL RAIN FOREST- cover 7% of earth’s surface and 40% of the world’s plant and animal species
  • SAVANNAH- most extensive in Africa.

fauna include grazers and browsers eg. antelopes, buffaloes, zebras, elephants, rhinoceros. 

carnivore include cheetah, hyena, rodents, etc.


dominant vegegation-grass

  • DESERT- flora are drought resistant like cactus, euphorbias, sagebrush

How are environmental science and ecology related

fauna- reptiles, small mammals, birds

Aquatic zones-

aquatic systems are not called biomes, they are divided into life zones with regions of relatively distinct life forms.

  • freshwater ecosystem

lotic-moving water eg. springs, brooks, rivers, etc.

lentic-still or stagnant water

physical, chemical, and biological characteristics varies. eg. pool, ponds, lakes, etc

  • marine ecosystem- three-quarters of the earth is covered by ocean 
  • estuaries-fresh water from rivers meets ocean water and both are mixed by the action of tides. Estuaries are highly productive as compared to an adjacent river or sea 
  1. coastal bays, river mouths, and tidal marshes
  • coral reef
  • mangrove

Part of earth where life exists.

it is a highly integrated and interactive zone of the atmosphere(air), hydrosphere (water), and lithosphere(land).

  • living organisms are uniformly distributed throughout the biosphere.
  • life is abundant between 200 meters below the surface of the ocean and about 6000 meters above sea level.
  • sometimes spores of bacteria and fungi are seen beyond 8,000 meters but they are present in dormant form. 


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