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Relationships in Ecosystem

Grade 9
May 30, 2023

Relationships in Ecosystem

What is a community?

A group of potentially interacting species living in the same location is called a community.


Difference between community and population:

community and population

Ecosystem: An ecosystem is a group of species that live together with non-living things. It includes all the living things such as plants, animals, microbes, etc., interacting with abiotic factors such as heat, light, water, food etc.

Living and Non-living things of Ecosystem



Population interaction:

  • Entities live in an ecological community, which is made up of at least two different species’ populations that are continually in contact with one another, either directly or indirectly, within a given geographical region.
  • When a definite group of species live in a certain ecosystem, they exhibit an effect on each other.
  • This phenomenon impacting nearby living and non-living beings is called population interaction.

Two types of Interactions:

Intraspecific interactions: These are biological interactions that occur between members of the same species.

Interspecific interactions: These interactions are biological interactions that involve individualism from distinct species.

Intraspecific interactions

Intraspecific and Interspecific Interactions
Intraspecific and Interspecific Interactions

Importance of Ecological Interactions:

  • Each organism flourishes and multiplies as expected in a healthy ecology.
  • Ecological balance is also vital because it leads to the constant existence of organisms.
  • It confirms that no particular species is exploited or overused.

Food Chain:

The sequence of transfers of substance and energy in the form of food from one creature to the next in ecology is called the food chain. The movement of energy in the food chain is unidirectional.

Food Chain
Food Chain

Food Web:

Food web consists of all the food chains in a single ecosystem. Every living thing in an ecosystem is part of multiple food chains. It is a more realistic interpretation of how food is utilized in an ecosystem.

Food web
Food web

Feeding Interactions in an Ecosystem:

The feeding interactions in an ecosystem are represented by food chains and food web. They demonstrate who eats whom.

Organisms in an ecosystem are linked in a variety of ways.

Some organisms may help each other, compete for resources, and, of course, eat each other. When one creature feeds on another, energy is transferred from one organism to the next.

Energy moves through an ecosystem in a single direction from the sun or inorganic compounds to autotrophs (producers) and then to heterotrophs (consumers).

Decomposers obtain energy from the decomposition of dead organisms.

A food chain describes the flow of energy across an ecosystem.

Food Chain and Food web
Food Chain and Food web


An ecosystem’s biotic component is a community. Their biological interactions, or interactions between different creatures in an environment are also included.

All living things depend on their surroundings to provide them with the necessities of life, such as food, water, and shelter. Physical variables including soil, air, and temperature, as well as other species, make up their environment. Many living creatures in their environment interact with other organisms.

In fact, they may require the help of other organisms to survive. It is called interdependence. Living beings that can’t create their own food must eat other organisms.

Ecological Interactions
Ecological Interactions

Predation: It occurs when members of one species (the predator) eat members of another species (the prey).

Lion and Buffalo Interaction
Lion and Buffalo Interaction

A predator-prey relationship has a tendency to keep the population of both species in balance.

Predator-prey Population Dynamics
Predator-prey Population Dynamics

As the population of prey increases, there are great chances of food for predators. Hence, after a slight lag, the population of predators increases as well. As predators increase, more prey will be captured. As a result, there is a decrease in the population of prey. Finally, the population of predators will also decrease.


Symbiosis is a Greek word means ‘living together’.

Symbiotic relationships occur when species have very close interactions with other species. It is a close and long-term association between two or more species. Symbiotic relationships benefit at least one interacting species. Symbiotic relationships are of three types.

Types of symbiosis:

Symbiotic relationships are classified into three types based on the behaviour of interacting species. They are as follows:

Mutualism: both the interacting species benefit from each other.

Commensalism: only one species is benefitted, and the other is harmed.

Parasitism: In this relationship, one species is benefitted, and the other is harmed.

Mutualism: It is a symbiotic relationship that benefits both species.

Bees and Flower interaction
Bees and Flower interaction

Bees rely on flowers as a food source. The bees pick up the pollen and transport it to other flowers. This helps in plant reproduction.

Hence, both are mutually benefited.

Another example is goby fish and shrimp.

Goby fish and Shrimps’ interaction
Goby fish and Shrimps’ interaction

Both species will spend most of their time together. The shrimps maintain burrows in the sand in which both reside. When predators come near, the fish touches the shrimp with its tail as a warning. Then, both retreat to burrow until the predator has gone. The shrimp gets a warning of approaching danger. The fish get place to lay eggs.

Commensalism: A commensalism is a form of relationship between two living organisms in which one organism will benefit from others without harming it.

Clown fish and Sea anemone interaction
Clownfish and Sea anemone interaction

Clownfish get protection from the sea anemone and the anemone is unaffected.

Another example is hermit crabs use the shell of dead snails for homes.


It’s a symbiotic relationship in which one species benefits (the parasite) while the other (the host) suffers.

Some parasites live on the host’s surface. Others make their home within their host.

They can get into the body of the host through a crack in the skin, food, or water. Roundworms, for example, are parasitic worms that infect mammals such as people, cats, and dogs.

Mosquito bite to Human
Mosquito bite to Human

Some parasites kill their host. If parasites kill its host, the parasite will also die. Generally, the worm produces large numbers of eggs that are passed to the host`s feces to the environment.

Competition: It is the struggle between organisms for the same resources such as food, water, or space in the same location.

When both organisms try to get the same resources in the same place at the same time, they are competing. Both creatures are likely to interact.

Two categories of competition: Interspecific and intraspecific competition

  1. Intraspecific competition occurs when members of the same species compete with one another. Two male birds of the same species, for example, may compete for mates in the same area.
  2. Interspecific competition occurs when members of different species compete with one another. Predators of various species, for example, may compete for the same prey.

Interspecific Competition and intraspecific Interaction

Interspecific Competition and intraspecific Interaction
Interspecific Competition and intraspecific Interaction

Ecological niche:

An ecological niche is the role and place of a species in its individual environment.

It describes the functional position of an organism in its environment, including the habitat in which it lives, the time when it is active, and the resources it uses.

A species niches includes interactions of all biotic and abiotic factors.

It is advantageous for species to occupy a distinct niche in an ecosystem because it reduces the competition for resources.

Ecological niches have distinct qualities that influence how a species survives and reproduces, such as nutrient availability, temperature, topography, sunlight, and predators.

Dung beetle
Dung beetle

The dung beetle consumes dung both in larval and adult form.

It stores dung balls in burrows, and females lay eggs within them.

This permits hatched larvae direct access to food.

The dung beetle, in turn, has an impact on the environment by aerating the soil and redistributing useful nutrients. As a result, the dung beetle plays a distinctive role in its surroundings.

How did the warbler partition their niche?

Dividing resources
Dividing resources

Here competition for food is reduced as each species of warbler prefers to feed in various regions of the tree.

It states that each warbler bird fills a different ecological niche within the forest ecosystem.

Relationships in Ecosystem


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