Nikaalo Prelims Spotlight || Basic Concepts of Ecology, Biodiversity

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This Spotlight is a part of our Mission Nikaalo Prelims-2023.

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YouTube LIVE with Parth sir – 7 PM  – Prelims Spotlight Session

Evening 04 PM  – Daily Mini Tests

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15th May 2023

Basic Concepts of Ecology, Biodiversity


  • Ecology is the study of the relationships between living organisms, including humans, and their physical environment; it seeks to understand the vital connections between plants and animals and the world around them
    • Also, Ecology also provides information about the benefits of ecosystems and how we can use Earth’s resources in ways that leave the environment healthy for future generations.
  • The term “ecology” was coined by the German zoologist, Ernst Haeckel, in 1866
  • Also, ancient Indian texts have references to Ecological principles as follows:
    • The classical texts of the Vedic Period such as the Vedas, the Samhitas, the Brahmanas and the Aranyakas-Upanishads contain references to ecological concepts
  • Further, a conceptual understanding of ecology is found in the broader details of study, including:
    • life processes explaining adaptations
    • distribution and abundance of organisms
    • the movement of materials and energy through living communities
    • the successional development of ecosystems, and
    • the abundance and distribution of biodiversity in context of the environment


  • Ecology mainly involves the study of biotic and abiotic factors with the environment
  • Biotic components include the living factors of an ecosystem.
    • Examples include bacteria, animals, birds, fungi, plants, etc.
  • Abiotic components include the non-living chemical and physical factors of an ecosystem
    • Examples include sunlight, soil, air, moisture minerals etc.

Types of Ecology

    • Microbial Ecology
      • Microbial ecology looks at the smallest fundamental levels of life, that is, the cellular level
      • Here, the connections are made between microbes and their relationships with each other and their environments
      • This is particularly important in the analysis of evolutionary connections and events leading to existence
    • Organism/Behavioural Ecology
      • This is the study of the organism at its fundamental levels and can encompass microbial ecology.
      • In this type of ecology, the main goal is to understand the organism’s behaviours, adaptations for such behaviours, reason for those behaviours as explained through the lens of evolution, and the way all these aspects mesh together
    • Population Ecology
      • Population ecology focuses on the population, defined as a group of organisms of the same species living in the same area at the same time
      • Here, attention is given to things such as population size, its density, the structure of the population, migration patterns, and the interaction between organisms of the same population.
    • Community Ecology
      • Community ecology takes a look at the community, defined as all the populations that live in a given area. This includes all the different species populations.
      • The focus here is usually on the interactions between the different species and how their numbers and sizes all mesh together and how change in one population change the dynamic of the whole community
    • Ecosystem Ecology
      • Ecosystem ecology makes a unique contribution to understanding ecology by adding abiotic (non-living) factors to the items analysed, alongside the biotic (living) factors involved.
      • This interaction therefore involves all aspects of the environment and how they interact
    • Global Ecology (Biosphere)
      • The global ecology is principally important in understanding all the ecosystems affecting the entire globe.
      • This includes all the different biomes, with considerations of aspects such as climate and other environmental geography

Examples of Ecology study

  • In recent years, the red panda population has dropped significantly, leading conservation groups to classify it as a vulnerable or endangered species
  • Ecologists have found that biotic factors, such as logging of trees and introduction of diseases from domestic dogs, played a major role in the decline of red panda populations
  • Abiotic factors have been less important to date, but changing temperatures could cause further habitat loss in the future
  • So, understanding the main ecological factors responsible for the decline in red panda numbers helps ecologists form conservation plans to protect the species

Levels of Organisation

  • Individual, Species, Organism
    • Organism in this level has the ability to act or function independently
    • Here, Individuals do not breed with individuals from other groups
  • Population
    • A group of individuals of a given species that live in a specific geographic area at a given time
    • Populations include individuals of the same species, but may have different genetic makeup such as hair/eye/skin colour and size between themselves and other populations
  • Community
    • It includes all the populations in a specific area at a given time. A community includes populations of organisms of different species
    • These are generally named after the dominant plant species
  • Ecosystem
    • Ecosystems include more than a community of living organisms (biotic) interacting with the environment (abiotic)
    • Everything that lives in an ecosystem is dependent on the other species and elements that are also a part of the ecological community
  • Biome
    • A Biome is a set of ecosystems sharing similar characteristics with their abiotic factors adapted to their environments
  • Biosphere
    • When we consider all the different biomes, each blending into the other, with all humans living in many different geographic areas, we form a huge community of humans, animals and plants, and micro-organisms in their defined habitats. A biosphere is the sum of all the ecosystems established on planet Earth

Principles of Ecology

  • Evolution organizes ecological systems into hierarchies
    • Individual organisms combine into populations, populations combine into species, species combine into higher taxa like genera and phyla.
    • Each can be characterized by its abundance and diversity (number of kinds) in a given ecosystem or study plot
  • The sun is the ultimate source of energy for most ecosystems
    • Life runs on the carbon-rich sugars produced by photosynthesis; every ecosystem’s sugar output depends on how much solar energy and precipitation it receives
  • Organisms are chemical machines that run on energy
    • The laws of chemistry and physics limit the ways each organism makes a living and provide a basic framework for ecology.
    • The supply of chemical elements and the sugars needed to fuel their assembly into organisms limit the abundance and diversity of life
  • Chemical nutrients cycle repeatedly while energy flows through an ecosystem
    • The atoms of elements like Carbon, Nitrogen and Sodium go back and forth from spending time in living to spending time in dead parts of an ecosystem.
    • But the photons of solar energy can be used only once before they are lost to the universe
  • Organisms interact—do things to each other—in ways that influence their abundance
    • Individual organisms can eat one another, compete for shared resources, and help each other survive.
    • Each pair of species in an ecosystem can be characterized by the kind and strength of these interactions
  • Ecosystems are organized into webs of interactions
    • The abundance of a population is influenced by the chains of interactions that connect it to the other species in its ecosystem
    • This often leads to complex behaviour, and a key challenge in ecology is to determine what patterns of abundance and diversity can be predicted
  • Human populations have an outsized role in competing with, preying upon, and helping other organisms
    • Humans are one of millions of species embedded in Earth’s ecosystems. The ability of humans to change the planet, abetted by our large population size and technological prowess, increases our ability to shape the biosphere’s future
  • Ecosystems provide essential services to human populations
    • These include products like timber, fibre and food, regulating water and air quality, and cultural benefits like recreation. A key goal of ecology is to use the above principles to preserve ecosystem services.


Biodiversity can be defined as a community of all the living organisms on the earth and the diversity among them from all the ecosystems. Biodiversity is thus the variability between the species, within the species, and between the ecosystem.

The term biodiversity was coined by Walter G. Rosen in the year 1986.

Types of Biodiversity

Biodiversity can be categorized into three main types:

  1. Genetic Diversity (Diversity within species)
  2. Species Diversity (Diversity between species)
  3. Ecosystem Diversity (Diversity between ecosystem)

Genetic Diversity

Every individual of a particular species differs from each other in its genetic makeup. This genetic variability among the members of any plant or animal species is known as genetic diversity. When two individuals are closely related, they share more genetic information and hence, are more similar.

Species Diversity

Species diversity can be defined as the variety of species within a particular region or habitat. This type of diversity can be found in both the natural ecosystem and agricultural ecosystem.

There are more than 85,000 flowering plant species in tropical North and South America, tropical and subtropical Asia has more than 50,000 flowering plants whereas, there are only 35,000 flowering plant species in tropical and subtropical Africa. But, Europe has around 11,300 vascular plants. Also, other areas, such as salt flats or a polluted stream, have fewer species.

Ecosystem Diversity

There is a large diversity of different ecosystems that have distinctive species. This ecosystem varies with each other as per their habitats and the difference in their species. This ecosystem diversity can be found within a specific geographical region or a country or a state. This type of diversity also includes forests, grasslands, deserts, and mountains.

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