Need Help?

Get in touch with us


Structure of Ecosystem: Levels of Organization

Jun 6, 2023

What is Ecology?


The study of how living organisms interact with the environment is known as ecology.

All living organisms must interact with biotic and abiotic factors that surround them. It informs us about the advantages of ecosystems and how we might use Earth’s resources in ways that preserve our environment for future generations.

Various Biotic and Abiotic Factors are as follows:

Biotic and Abiotic factors



We know that all living things depend on other living or non-living factors for their survival. Thus, all living things are interdependent. Interdependency is particularly important for survival. Every day we share our environment with various organisms such as plants, animals, etc.

The study of plants and animals, and their interaction with their surroundings, is called natural history. The area of biology formed from natural history is called ecology. Ecology is the study of communication between organisms and their surroundings.

Organization in biology is defined as the hierarchy of complex biological structures and systems. Each successive level of the biological hierarchy reveals a greater amount of organizational complexity.

Cellular level of Organization



Ecologists study individual organisms, communications among organisms of the same species, various species, and also the effects of abiotic factors on interacting species. To understand the interactions of biotic and abiotic factors, ecologists have organized living things into various levels, i.e., organism, population, community, and biosphere.

There are five levels of organization from smallest to largest, based on their size.

Organism à Population à Community à Ecosystem à Biosphere

Ecological level of Organization

Ecological Levels of Organization:


Organisms are the simplest form of organization, and it includes both unicellular and multicellular organisms.

An organism is any living thing such as plant, animal, fish, or bird.

Characteristics of organism: All organisms need food to survive, oxygen to breathe, respond to external stimuli, they show the property of excretion, they reproduce, and they move from one place to another.


It is a group of organisms of the same species that live in the same area at the same time.

For example, herds of elephants, pods of whales, army of frogs, etc.

Types of population:

The local population can be constrained to a particular area or can occupy a greater area, thereby representing the entire species.

Members of the population may struggle for food, shelter, mate, and other resources. When the supply of resources is less, the competition among the population increases. Certain species have adaptations with the environment that reduces the chances of competition in population.

For example, in the life cycle of a frog, the young tadpole and adult frogs have different food requirements. Tadpoles eat algae whereas adult frogs eat insects. Hence the competition for food is not seen at this stage.

Individuals in local populations spread between other local populations, resulting in a metapopulation.

A metapopulation is a population with two or more subpopulations physically distributed in the same habitat. Butterfly populations and coral-reef fish populations are wonderful instances of metapopulation.

They breed with each other and compete with each other for resources.


It refers to the various populations that interact and inhabit a common environment and are interdependent.

For example, birds, wild animals, dogs, and deer all together in a single area.

Generally, species do not live alone. Every population shares its surroundings with other populations. The combination of various populations results in the formation of biological community. Changes in one community may lead to changes in other communities too.

For example, if there is a slight increase in the number of snakes within a community, then the number of rats will gradually decrease.

Some extreme changes can also be seen in a community. For example, if the population of one organism grows faster, then it may threaten the survival of other populations. In forest community, there are many populations, and they depend on each other for food. Such as birds eat insects, squirrels eat nuts, fungi grow on dead and decaying matter of leaves and stems.

These populations depend on each other, and they get affected by abiotic factors such as soil, water, temperature, etc. Such a relationship between different populations leads to the development of an ecosystem.

It refers to the interdependence of many communities that interact and share a common environment.


It is the collection of all living species and abiotic components that exist in a given habitat and interact with one another. There is an interaction with both living and nonliving components of the environment.

When you study ecosystem, you look at how the living and non-living elements interact and affect each other.

Types of Ecosystems

On the basis of habitat, ecosystem is divided into two groups—terrestrial ecosystems and aquatic ecosystems.

Terrestrial ecosystem: These are located on land. For example, fields, rotting logs, yard, meadows, volcanoes, and garden plot.

Land based ecosystems are terrestrial ecosystem, grassland, tundra, and desert ecosystems

Aquatic ecosystem: These occur in freshwater and saltwater. Freshwater ecosystem consists of ponds, lakes, and streams. Saltwater ecosystem consists of wetland, estuaries, and marine ecosystem.


It is the most senior level of management. It is the global ecological system, which includes all living organisms and other conditions that enable life to exist. It generally refers to the part of the earth’s crust that is below the surface.

All living organisms are not equally distributed throughout the biosphere.

The biosphere encompasses everything from tree roots to ocean trenches, lush rain forests, towering mountaintops, and transition zones like this one, where ocean and terrestrial ecosystems collide.

For example, the polar regions are home to only a few organisms, but tropical rainforests are home to an incredible variety of flora and animals.

Difference Between Population and Community

population and community

Difference Between Population and Community

Community Interactions:

Many various species intearcting in a same environment is reffered as community interactions.

The different types of interactions in communities are at the reproductive and behavioral level

Types of Community Interactions:

Types of Community interactions

In predation, member of one species, predator, eats a member of another species known as prey. It is beneficial for predators only.


Mutualism: It involves a long-term interaction between two species where both species get the benefit.


Ants eat the honeydew excreted by the aphids and in turn, provide protection to aphids from any other insects.

Parasitism: It is a long-term association between two species that is beneficial for one and harmful for another. 


Here, the host caterpillar dies eventually as its organs are consumed by wasp larvae. Braconid larvae feed on caterpillars and release themselves shortly before reaching pupae stage of development

Competition: In competition, species compete for limited resources such as water, nutrients, food, and light.

Competition has a negative impact on both participants. It entails a mutually unfavorable interaction between organisms with limited resources such as food, nutrients, water, and so on.

Competition of Squirrel and Bird for Nuts and Grains

As the environment changes, so does the outcome of encounters. Some of these interactions will likely boost variety, while others will likely decrease it. One of a community’s most significant traits is diversity.

Levels of Organization


Related topics


Mutation Theory of Evolution and Types

Introduction: Cell is the basic unit of living organisms from bacteria to humans all are made up of cells, which contain a nucleus and the nucleus contain DNA Explanation: Mutations is a sudden changes in chromosomal DNA., They cover only those changes that alter the chemical structure of the gene at the molecular level. These […]


Lamarckism: Postulates and Drawbacks

Introduction: Evolution states that distinct types of plants, animals, and other living organisms on Earth have their origin in pre-existing life forms. It is a variation in the inherited characteristics (traits) of biological populations over successive generations. These traits are the expressions of genes that are passed on from parents to offspring in the course […]


Biodiversity: Classification of Living Organisms

Introduction to Biodiversity: Fig No.1 Biodiversity Classification Fig No.2 Different organisms The Characteristics of Living Organisms Fig No. 3 Classification Diversity in Living Organisms The Five Kingdom Classification The five kingdoms in this widely accepted classification are made up of species with similar growth and functioning characteristics. Organisms are classified into five kingdoms based on […]


Mitochondria – The power House of a Cell

The Cell Organelles – Mitochondria  Introduction: Powerhouse Of Cell Mitochondria are primarily responsible for converting nutrients into energy. They yield ATP molecules to fuel cell activities. As they do aerobic respiration, mitochondria are often referred to as the powerhouse of the cell. There are three stages of aerobic respiration. Those three stages are: Origin Of […]


Other topics