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Ecology: Types, Significance, Practice Problems and FAQs

We live in an environment by interacting with the various abiotic and other biotic (plants, microorganisms etc.) components. We all are a part of nature and nature consists of complex, interdependent and interrelated entities. All these interactions are necessary for sustaining life on the Earth.

Environment means the surroundings of an organism in which it lives. It is considered as the sum total of all abiotic (non-living) and biotic (living) factors that surround and influence an organism. The organism can survive only in an appropriate environment. Ecology deals with the various principles that govern the relationships between organisms and their environment. Ecosystem is a segment of nature which consists of a biological community integrated with its physical environment through transfer of energy and cycling of nutrients. For example, in India, there are different types of ecosystems present, such as grasslands, rivers, ponds, deserts, lakes, and many more.

Fig: Global ecosystem

Have you ever thought about what the study of an ecosystem is called or why do we study the ecosystem?

Yes, the study of ecosystems is known as Ecology. We study ecology to gain knowledge of interdependence between organisms and nature. It is required to maintain a balance on Earth which can in turn sustain life on Earth. There are different types of ecology which we are going to discuss in this article. So, let’s take a deep dive into the details of ecology, its types and gain more information about it.

Table of contents

  • Ecology
  • Biotic and abiotic components
  • Types of ecology
  • Significance of ecology
  • Practice Problems
  • FAQs


Human science, population, community, ecosystem, and biosphere are all included in the scientific field of ecology. Ecology is the study of species, their environments, and the interactions that occur between them. It is studied on many different scales, including the organism, population, community, biosphere, and ecosystem. The main objective of an ecologist is to gain a better understanding of how an organism functions, their adaptations, environments, interactions, and biodiversity.

The term ‘Ecology’

The term ecology was introduced by a German biologist Ernst Haeckl in 1866. Ecology is formed from two Greek words. ‘Oikos’ in Greek means ‘place to live or house’, ‘logos’ means ‘to study or discourse’. Ernst Haekel is the father of ecology. He provided the first definition for ecology which states that “ by ecology we mean the body of knowledge concerning the economy of nature - the etotal relations of animals to both its inorganic and organic environments”

Biotic and Abiotic components

The primary goal of ecology is to understand how biotic and abiotic components are distributed in an environment. The living and nonliving elements, as well as their interactions with the environment, are included in the biotic and abiotic factors.

Biotic components

Biotic components include all living organisms, such as plants, animals, man, algae, fungi, bacteria, viruses, etc., and their waste materials. The biotic components are further classified into three categories as follows:

  • Producers
  • Consumers
  • Decomposers

Fig: Biotic components of the environment


Producers are autotrophic organisms that prepare their own food. Producers like plants prepare their own food through the process called photosynthesis. The producers include phytoplankton, cyanobacteria, algae and green plants. The food chain starts from the producers. They occupy the first trophic level in the food chain and need mostly solar energy to prepare their food. Examples include plants, photoautotrophs, and phytoplanktons.

Fig: Producers


They are also known as heterotrophs. Consumers include those organisms that directly or indirectly depend on producers for their food. They are further categorised into various groups such as herbivores, carnivores, omnivores, scavengers and parasites.

Fig: Consumers


Herbivores are those organisms that rely only on plants for their food. They exist in the range of tiny insects to the large elephant. Herbivores are known as primary consumers. Examples include deer.

Fig: Deer


The organisms that eat other organisms are known as carnivores. They eat meat or flesh of other organisms. Carnivores eat herbivores or other small animals. Examples include lions, tigers etc.

Fig: Tiger


The organisms that consume plants, as well as animals, are known as omnivores. Examples include human beings, dogs, bears, and many more.

Fig: Human being


A parasite is an organism that lives on or inside a host organism and obtains nutrition from or at the expense of the host. Parasitism is the type of population interaction here. The organism that is benefitted is called the parasite, while the one that is harmed is called the host. Examples includeticks (parasites) on dogs (host).

Figure : Ticks on dog


Scavengers are those living organisms that feed on dead biomass, such as meat or rotting plant material.These form the first level of the detritus food chain.Examples include jackals, hyenas, and wolves.

Fig: Hyenas waiting for leftover meat


These are a type of organisms that feed on the dead and decaying matter for their nutrition. They are heterotrophic organisms that convert organic substances into inorganic molecules and form nutrient-rich soil. These are normally microscopic organisms which help in chemically breaking down the complex organic compounds in freshly deposited detritus or fragmented detritus to simpler inorganic minerals or turning them into organic humus. Examples of decomposers include bacteria and fungi.

Fig: Fungi


These are animals which feed on freshly deposited detritus and fragments left over by scavengers and help in fragmenting and pulverising it. These include millipedes, earthworms, beetles, etc.

Fig: Earthworm

Abiotic components

Abiotic components include all non-living things present in the environment, such as air, water, soil, humidity, temperature, etc. These are essential for the survival of biotic components. Both biotic and abiotic components interact with each other to form an ecosystem.

Fig: Abiotic components of the environment

Types of ecology

It is difficult to research and understand how biotic and abiotic components interact, as a result, there are various ecological study levels that are formed according to their benefits and uses. The various types of ecology are listed below:

  • Global ecology
  • Landscape ecology
  • Ecosystem ecology
  • Community ecology
  • Population ecology
  • Organism ecology
  • Behavioural ecology
  • Deep ecology
  • Human ecology
  • Molecular ecology

Global ecology

Global ecology deals with the Earth’s ecosystem. The study of how ecosystems on Earth interact with the geosphere, hydrosphere, and atmosphere is known as global ecology. To understand how to lessen the effects of human activity on the planet, it is essential to understand global ecology. An example of global ecology would be the summertime wildfires in the United States, which are frequently happening due to camping or lightning. In addition to destroying habitats, extensive fires burn a large amount of land, which results in air pollution that extends far beyond the borders of the fire. This type of ecology primarily focuses on comprehending large-scale interactions within a broader context.

Advantages of global ecology

The following are the major advantages of studying global ecology:

  • This type of ecology is crucial because it expresses the effects of climate change.
  • The kind of plants that can grow in a region change as a result of increased greenhouse gas emissions. As a result, this alters the types of species that can inhabit the area.
  • The Earth is steadily growing warmer as it gets closer to the poles. Arctic ice formation has decreased significantly from earlier times. All this information is available because of global ecology.
  • It helps in better survival on the Earth.

Fig: Global ecology

Landscape ecology

It deals with the flow of materials, organisms, energy, and other ecological byproducts. The influence of human activity on the structures and functions of the landscape is highlighted by landscape ecology. It involves the interaction between the spatial and temporal aspects of the landscape and the organisms living within it. This helps in understanding the distribution of fauna and flora.

Fig: Landscape ecology

Ecosystem ecology

The study of the components of ecosystems and their interactions is referred to as ecosystem ecology. In a nutshell, the study of interactions between biotic (living) and abiotic (non-living) elements within an ecosystem framework is known as ecosystem ecology. An ecosystem is composed of different structural components, such as organisms and their physical environment. These components interact among themselves through several processes, such as energy flow and cycling of materials. These interactions between biological and physical components accomplish the goal of the continuance of life. Each ecosystem depends on the other in some way, thus none of them are independent.

Fig: Ecosystem ecology

Two main processes in the ecosystem

The components of the ecosystem interact through two main processes as follows:

  • Food chains
  • Biogeochemical cycles

Food chains

Food chain is described as a chronological series of organisms each depending on other organisms for food. It describes which organism in an ecosystem consumes other organisms. In a food chain, nutrients and energy are passed from one creature to the next in a sequential order. This occurs when one animal eats another. The food chain starts with the producer and ultimately ends with the decomposer. A trophic level describes the successive stages of a food chain, starting with producers at the bottom and moving up to primary, secondary, and tertiary consumers. Therefore, we can say that the trophic level is any point in the food chain. Examples include grazing food chain or GFC and detritus food chain or DFC.

Fig: Grazing food chain (GFC)

Biogeochemical cycles

Nutrient cycle is also termed asbiogeochemical cycle. It is the movement of nutrients through various components like living and nonliving parts of an ecosystem. The nutrient cycle is of two types based on their major reservoir as follows:

  • Gaseous cycle
  • Sedimentary cycle

Gaseous cycle

The reservoir of thegaseous cycle is present in the atmosphere. Examples include carbon, oxygen and nitrogen cycles.

Sedimentary cycle

On the other hand, the reservoir of thesedimentary cycleis present in the Earth’s crust. Examples include phosphorus and sulphur cycles.

Fig: Types of nutrient cycles based on their major reservoir

Community ecology

It focuses on how interactions between living things alter community structure. An ecology community is made up of two or more populations of various species that are localised in a particular geographical area. For example, the different species of plants and animals in a pond or lake form one biotic community. Similarly, several species of plants and animals in a particular forest constitute another biotic community.

Fig: Community ecology

Types of communities

There are primarily two types of communities as follows:

  • Major community
  • Minor community

Major community

It is a large community that functions as a self-governing, self-sustaining, and independent unit and includes a number of smaller communities. Examples include a pond, a lake, a forest, a desert, a grassland, and a meadow. Each of these major communities includes various minor communities.

Fig: Pond ecosystem

Minor community

It is a more compact community, not a self-sustaining entity. It cannot exist without the assistance of other communities. For example, there are three main minor communities in the forest main community. It includes the plant community (the various plant populations of the forest), the animal community (the various animal populations of the forest), and the microbiological community (the various bacteria and fungi populations of the forest).

Fig: Minor communities in a forest main community

Characteristics of a community

A community possesses the few characteristics as follows:


The density, frequency, and abundance of species can be used to study the structure of a community.


Typically, a community has one or more abundant species. These are known as dominating species, and the community is frequently named after them. For example, in a grassland, the dominant species include grasses.

Fig: Grassland


The community is made up of several species of both large and small plants and animals. There are different life forms but all are growing in the same general environment.


This includes the study of the different life processes (respiration, growth, reproduction, etc.) carried out by the dominant species in a community throughout the various seasons of the year. Periodicity is defined as the recurrence of these crucial biological processes at regular intervals throughout the year and their manifestation in nature.

Fig: Reproduction


It is the vertical distribution of species at different levels in an ecosystem. In natural forest communities, there are several strata or layers based on the height of the plants. For example, if you consider a forest, then trees occupy the top vertical strata. Shrubs occupy the second level, herbs occupy the next level and grasses occupy the bottom layer.

Fig: Stratification in the forest ecosystem

Ecotone and edge effect

The changes in population or community structures that normally occur at the boundary of two habitats is called ecotone. For example, the region of vegetation that runs between or separates two distinct types of ecosystems. These are clearly identifiable peripheral zones. Ecotones typically have a greater variety of one species than any of the nearby groups. The number of species and the population density of some of the species in the ecotone is much greater than either community in certain cases. This is called the edge effect. This occurs due to the reason that there are environmental conditions in this region that are ideal for growing plants.

Fig: Edge effect

Population ecology

Population ecology deals with the processes that affect the distribution and abundance of populations of different species, such as plants and animals. A population is defined as a set of individuals of the same species living in the same geographical area at a particular time.

Fig: Population ecology

Factors affecting population

There are four main factors that increase or decrease the population size. These are listed below:

  • Birth rate
  • Immigration
  • Death rate
  • Emigration

Birth rate

Birth rate refers to the per capita births in a population. It is also known as natality.

Birth rate (b) =Number of individuals added/Initial population

For example, if in a pond 20 lotus plants were present last year and 8 new plants are added through reproduction, taking the current population to 28,

= 8/20

= 0.4 offspring per Lotus per year.


It is the number of individuals of the same species that have come into the habitat from elsewhere during the time period under consideration..

Death rate

Death rate refers to the per capita deaths in a population. It is also known as mortality.

Death rate (d) = Number of individuals died/Initial population

For example, if in a laboratory population of 40 fruit flies, 4 flies died within a week,

= 4/40

= 0.1 individuals per fruit fly per week.


It is the number of individuals of the population that have left the habitat and gone elsewhere during the time period under consideration.

Immigration and emigration assume importance only under special conditions. For instance, when a new habitat is just being colonised, immigration may contribute more significantly to population growth than birth rates. The number of births and deaths in a population depend on various factors like fertility rate, food availability, environmental conditions etc. and are not necessarily equal.

Organism ecology

The study of an individual organism's behaviour, morphology, physiology, etc., in response to environmental conditions is known as organism ecology. It examines the interactions between certain species and biotic and abiotic elements. Ecologists study how organisms adjust or adapt to these living and non-living elements of their environment. Pheromones that aid in the attraction of female insects, the existence of a symbiotic partner that aids in the acquisition of energy and nutrients, or a feature that aids a species in adapting to climate change are examples of these adaptations.

Fig: Organism ecology


Adaptation is an attribute of an organism that allows the organism to survive and reproduce in its environment. There are three types of adaptations as follows:

  • Morphological adaptations
  • Physiological adaptations
  • Behavioural adaptations

Morphological adaptations

It is described as a structural change that gives an organism a greater chance of survival in its habitat. Some desert plants like Cactus orOpuntiapossess modified flat stems called phylloclade to carry out photosynthesis. Their leaves are reduced into spines to prevent water loss by transpiration.

Fig: Morphological adaptations in desert plants to prevent water loss

Physiological adaptations

Internal organs, tissues, and cells are all included in the term ‘physiological adaptations’. An organism's cellular structure, internal organs, hormone fluctuations, mood swings, and other characteristics aid in this sort of adaptation by enabling it to survive, adapt, and react to environmental changes. Examples include altitude sickness, in which a person is not getting enough oxygen due to high altitude and low atmospheric pressure. The symptoms of this situation include nausea, fatigue, and heart palpitations. The body compensates for this situation by increasing the production of red blood cells and breathing rate.

Fig: Comparison of density of air at sea level and mountain top

Behavioural adaptations

This type of adaptation is described in a way an organism reacts to its environment that helps in its survival. Desert lizards have behavioural adaptations to keep a steady body temperature throughout the day since they are unable to acquire physiological adaptations to withstand the scorching desert climate. When their body temperature begins to drop below what is comfortable for them, they go outside in the morning to warm up in the sun. However, when the temperature outside gets too hot, they migrate indoors or under covers. When the surface temperature rises too much due to the heating of the sand, some desert animals frequently hide in burrows.

Fig: Behavioural adaptations seen in desert lizard

Behavioural ecology

It studies the different ways by which an organism evolves and adapts to changes in their habitat. It includes studies related to the food source of the organism, its reproduction, its predators and the characteristics of its habitat. It also includes studying the mating patterns or the characteristics female and male animals use when going to reproduce such as bird songs or plumage related to mating patterns. For example, Wilson’s Bird of Paradise (Lophorina superba), shows mating dance.

Fig: Wilson’s Bird of Paradise (Lophorina superba)

Deep ecology

It is a new area of study. It proposes that human beings normally function as a part of the environment, not against it. This ecology is not dependent on the normal scientific method of studies like first asking a question, then proposing a hypothesis, and finally testing the proposed hypothesis. It is more related to political science and philosophy.

Human Ecology

This ecology focuses on the relationship between humans with their environment. It emphasises the impact of anthropogenic actions on the environment. It also gives information about how the environment can be improved by anthropogenic actions. This is required to improve the conditions of humans and the environment.

Fig: Human ecology

Molecular Ecology

The study of ecology focuses on the production of various molecules and how these molecules normally affect the organisms and their environment is called the molecular ecology. For example, DNA forms mRNA by transcription, from mRNA the proteins are formed then by translation. This is called central dogma. Now these proteins help the organisms to interact with each other and with the environment.

Fig: Central dogma

Significance of ecology

There are different reasons that explain the importance of ecology as follows:

  • Conservation of environment
  • Resource allocation
  • Energy conservation
  • Eco-friendliness

Conservation of environment

Ecology enables us to understand how human behaviour impacts the ecosystem. It demonstrates the depth of the environmental harm we cause to the environment. The environment and the land have deteriorated as a result of a lack of ecological knowledge. A few species have also become extinct or are in danger as a result of it.

Resource allocation

Ecology enables us to understand which resources are essential for the existence of various organisms. Lack of ecological knowledge has caused these resources to be restricted and exploited, which has increased competition.

Energy conservation

Energy is necessary for all living things to grow and develop. Lack of ecological knowledge results in the overuse of energy resources like light, food, and radiation, which causes their depletion. Proper understanding of ecological requirements helps to conserve energy for future uses by preventing excessive use of energy resources.


Ecology encourages harmony within the species, with other species and with the environment. The adoption of a better and balanced lifestyle always protects the environment and sustains life on Earth.

Practice Problems

  1. Determine the closely related statement with ecological diversity?
  1. Numerous species present in a large population
  2. A country or other huge geographical mass with a variety of habitats, including desert, rainforest, and mangrove
  3. Species from several geographic areas are present in an ecosystem
  4. Few species occupying an area

Solution: The term ‘ecological diversity’ refers to the wide variety of ecosystems that can be found within a very large geographical area. For instance, India is home to a variety of habitats, including deserts, tropical rainforests, mangroves, wetlands, coral reefs, estuaries, and more. India is therefore claimed to have more ecological diversity than a Scandinavian nation, which is primarily home to frigid, subpolar habitats. Hence, the correct option is b.

2. Ecology is defined as the study of relationship between ______________

  1. Members of a family
  2. Man and environment
  3. Organisms and environment
  4. Soil and water

Solution: Ecology is the study of species, their environments, and the interactions that occur between them. It is studied on many different scales, including the organism, population, community, biosphere, and ecosystem. The main objective of an ecologist is to gain a better understanding of how an organism functions, their adaptations, environments, interactions, and biodiversity. Hence, the correct option is c.

3. Which is the basic unit of ecological hierarchy?

  1. Population
  2. Organism
  3. Community
  4. Ecosystem

Solution: The individual organism is the fundamental unit of the ecological hierarchy. Populations are involved in the second level. A population is a collection of members from the same species living in the same region and interacting with one another. The community occupies the third level of the ecological hierarchy. The relationship between various species within a community is given main emphasis at the community level. Ecosystems are the next level up. An ecosystem is made up of both living and nonliving elements that interact with one another and with the nonliving elements. A solitary lake, a forest, or a mountain are examples of ecosystems. Hence, the correct option is b.

4. How species diversity is different from ecological diversity?

Answer: The phrase ‘species diversity’ refers to the variety seen at the species level in an ecosystem or area in consideration. It shows the actual abundance of various species in a region. On the other hand, the word ‘ecological diversity’ refers to the variety of ecosystems (such as deserts, forests, grasslands, wetlands, and oceans) within a given geographic area.


  1. How are new species formed?

Answer: A new species emerges when a species is dispersed across a wide geographic area but only reproduces with nearby species or when individuals split off into smaller groups due to various reasons and create a new species.

  1. Why do organisms show different types of behaviour?

Answer: Animals develop a variety of behaviours to adjust with their environment or habitat These behavioural actions assist them for better survival or reproduction. For example, frogs and toads produce mating calls by crocking with vocal sacs during the breeding season. The males frogs are more vocal and louder than the female frogs.

GIF: Male frog making mating calls

  1. How are humans responsible for destroying the ecosystem?

Answer: Numerous human activities such as overpopulation, pollution, the burning of fossil fuels, and deforestation have an adverse effect on the physical environment. These types of modifications have led to climate change, soil erosion, poor air quality, and non potable water.

  1. Which ecosystem is the largest ecosystem on the Earth?

Answer: The ocean is the largest ecosystem on the earth. It covers 71% of the Earth’s surface.

Fig: Ocean ecosystem

Related Topics

Food chain: Trophic levels, Types of the food chain, 10% law, Grazing food chain vs detritus food chain, Food web, Practice Problems and FAQs
Nutrient cycling: Carbon cycle and Phosphorus cycle, Practice Problems and FAQs
The Ecosystem - Components, Structure and Functions, Practice Problems and FAQs
Biomass, Primary Productivity, Secondary Productivity, Practice Problems and FAQs
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