Ecology and Ecosystem

Published on 04 Apr 2025

Ecology 

• Definition: According to Ernst Haeckel, Ecology is the study of the relation of the animal to its organic and inorganic environment. 

• Example: Bees collect nectar for honey, and in return, help in pollination.

• There are 5 main levels of organization of ecology:

1. Individual

2. Population

3. Community

4. Ecosystem

5. Biosphere

Ecosystem

• Definition: An ecosystem is a structural and functional unit of ecology. It is defined as the system resulting from the integration of all the living and non-living factors of the environment. The term “Ecosystem” was first coined by an English Botanist named A.G Tansley. 

• Example: Grassland ecosystems dominated by grasses where grazing animals, such as cattle, goats, and deer are found

Components of an ecosystem

The components of the ecosystem are classified into abiotic or non-living and biotic or living components.

• Abiotic components are the inorganic and non-living parts. Basic abiotic factors include:

• Temperature: Affects metabolism and growth rates of organisms, and regulates biochemical reactions.

• Water: Provides a medium for chemical reactions, supports aquatic life, and transportation of nutrients and waste.

• Light: Provides energy for photosynthesis, and regulates biological rhythms and behaviour.

• Soil: Provides a medium for plant growth, supports nutrient cycling, and acts as a habitat for microorganisms.

• Biotic components are living organisms, including plants, animals, and other organisms. Biotic components are further classified into three:

• Producers/ Autotrophs: It includes green plants with chlorophyll, certain bacteria, and algae, which can prepare their own food through a process termed Photosynthesis.

• Example: Grass, Cyanobacteria

• Consumers/ Heterotrophs: Since they are incapable of preparing their own food, they depend on producers for food. They can be classified as Herbivores, Carnivores, Omnivores and Detritivores.

• Example: Rabbit, Elephant

• Reducers/ Decomposers: Reducers, also known as Detrivores, are responsible for breaking down dead organic matter. Decomposers, also known as saprotrophs, finish the process by breaking down the dead remains into smaller nutrients.

• Example: Worms, vultures, fungi 

Factors influencing ecosystem 

Ecosystems are influenced by different factors, both biotic and abiotic factors. These factors support the health, stability, and function of the ecosystem. Some of these factors that influence ecosystems are:

• Climate: Temperature, humidity, and precipitation are a few climatic factors that determine the plants and animals that can survive in a particular region.

• Topography: The physical features such as mountains and water bodies can also impact the distribution of species.

• Biotic interactions: Biotic interactions such as predation, competition, mutualism, and symbiosis play an important role in shaping the ecosystem.

• Soil Quality: Soil texture, pH, and nutrients are major factors in determining the types of plants that can grow, which eventually influences the food chain of that region.

• Nutrient cycling: Carbon cycling, nitrogen cycling, and phosphorus cycling are essential for the functioning of ecosystems.

• Human activities: Anthropogenic activities like deforestation, pollution, etc. can lead to habitat loss and species decline.

Ecological niche VS Habitat

Principles of ecology

The major principles of ecology depend upon the study of interactions between organisms and their environment. These principles include:

• Adaptation: The appearance or behaviour or structure or mode of life of an organism that allows it to survive in a particular environment.

• Example: In aquatic flowering plants, there is an absence of wood formation and a highly reduced root system.

• Variation: It can be defined as any difference between the individuals in a species or group of organisms of a species. They are induced by changes in genetic makeup due to the addition or deletion of certain genes.

• Example: The difference in skin colour, eye colour, and blood type among different ethnic groups represents the variation within the human species.

• Interdependence: The survival of an organism depends upon the relationship of this organism with other species and their environment.

• Example: Bees help in pollinating flowers, and, in turn, flowers provide bees with nectar.

• Speciation: It is how a new kind of plant or animal species is created. This occurs when a group within a species separates from other members of its species and develops its own unique characteristics.

• Example: Galapagos finches living on different islands in the Galapagos archipelago have distinct morphology.

• Mutation: It is a change in the structure of a gene, the unit of heredity. It can be considered as the engine of evolution in that generates the genetic variation on which the evolutionary process depends.

• Example: Animals born with extra body parts, such as two-headed snakes and four-legged ducks.

• Natural selection: It is a mechanism of evolution in which organisms that are more adapted to their environment have higher chances to survive and pass on the genes that aided their success.

• Example: Evolving long necks have enabled giraffes to feed on leaves that others can't reach, giving them a competitive advantage.

• Evolution: It is the process by which species adapt over time in response to their changing environment. This can be induced by geographical phenomena like continental drift, glacial cycles, etc.

• Example: Human evolution

• Extinction: It is the complete disappearance of a species from Earth.

• Example: Extinction of Woolly mammoth.

  Functions of an ecosystem

  • Energy Flow: The flow of energy from one trophic level to another trophic level is known as energy flow and it is unidirectional.

  • Nutrient Cycling: Also known as Biogeochemical cycles, it describes the movement of chemical elements through different media, such as the atmosphere, soil, rocks, and water bodies. They can be divided into two:

  • Gaseous cycles: They take place in the atmosphere or oceans through evaporation. They include the carbon cycle, oxygen cycle, nitrogen cycle, and water cycle.

  • Sedimentary cycles: It takes place in the earth’s crust. These cycles include chemical components such as iron, phosphorus, sulfur etc.

  • Homeostasis or feedback control mechanism: It is the ability of an organism to maintain a stable internal environment by regulating pH, temperature etc. regardless of external challenges. Regulate, Conform, Migrate, and Suspend are the methods that help in attaining stable equilibrium.

  Ecological succession or ecosystem development: Ecological succession is the process by which communities of plants and animals carry out gradual and predictable changes in their structure and composition over time.

  
  

Tags:
Environment

Keywords:
Ecology Ecosystem Ecological niche Habitat

Syllabus:
General Studies Paper 3

Topics:
Environment and Climate Change