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Ecology

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Ecology

Have you ever stepped into your garden and noticed the incredible display of nature, from ladybirds crawling on leaves to worms burrowing in the soil to bees buzzing around flowers? Or have you been to the beach and seen the variety of marine organisms that are washed ashore, like crabs, barnacles, or seaweed? If yes, then you have witnessed ecology in action!

  • First, we'll discuss the definition of ecology and what it seeks to explain.
  • Then, we'll have a look at the different components of an ecosystem.
  • Finally, we will tackle ecological concepts you might encounter: ecological niche, population ecology, and ecological succession.
  • As a bonus, we will also touch on the concept of human ecology, a concept that was inspired by the biological concept of ecology and is popularly used in the social sciences.

Ecology Definition

Ecology is the branch of biology that helps us to understand everything from the surrounding organisms to the environment that they live in.

It helps us understand how these organisms interact with each other and the surrounding environment.

People who study, and research, ecology are called ecologists. Ecologists seek to explain:

  • Interaction between living organisms

  • How organisms interact with their habitats

  • Energy transfer between organisms

  • The distribution of living organisms in the world

Ecology System

A system in ecology means a specific community of biological and physical factors that interact with each other. These components are called biotic and abiotic factors, respectively. Ecological relationships depend on the dynamics between abiotic and biotic factors.

Biotic factors are living things within an ecosystem. They also include organisms that were once living. Examples of biotic factors include animals, fungi, plants, bacteria, and more.

Abiotic factors are non-living factors in the environment. This includes weather conditions, such as temperature, humidity, wind speed, and light intensity, among many other factors.

If you are eager to learn more about this, read our article on Biotic and Abiotic Factors!

A major part of ecology is to understand how and why living organisms live in the places they do or why their populations increase or decrease. Biotic factors and abiotic factors influence these patterns.

  • Biotic and abiotic factors both play crucial roles in the functioning of an ecosystem. Any changes in an area's biotic or abiotic factors will impact the ecosystem's dynamic.

To understand what biotic and abiotic factors are, let’s take the example of woodlice.

Woodlice prefer damp environments, such as moist soils. This is why you may find them crawling in the soil in your garden. Soil moisture is an example of an abiotic factor, a non-living component of the environment that affects how living organisms are distributed (spread).

In terms of feeding, woodlice feed on organic matter like plants. This is why woodlice are found in gardens. Plants are biotic factors, a living component of the environment that affects how living organisms are distributed.

Ecological Niche

Ecological niche describes the role that an organism plays within a community. This includes all biotic and abiotic factors that influence this organism.

When talking about the ecological niche of an organism, we have to consider factors such as:

  • The abiotic factors that an organism can tolerate, such as weather conditions, humidity, and more.

  • The resources that these organisms require. This could include water required by the organism, and food.

  • How this organism interacts with other organisms. This includes whether it competes with other organisms for resources, whether it acts as a pest or whether it is involved in a predator-prey or mutualistic relationship.

Competition can be interspecific or intraspecific. Interspecific competition refers to a situation where organisms have to compete with organisms of another species for resources. Intraspecific competition refers to a situation where organisms have to compete with organisms from their own species for resources.

There are many types of relationships behind organisms that we have to consider when thinking about an ecological niche. +/- relationships involve relationships where one organism benefits, whilst the other suffers. We call such relationships parasitic.

Examples of this would be predator/prey interactions or competition.

Another type of relationship is a +/+ relationship, which is a relationship where both organisms benefit. Such relationships are called mutualistic.

An example of this is the relationship between the spider crab and algae. Spider crabs live in shallow areas of the ocean floor, while greenish-brown algae live on the crabs' backs, camouflaging the crabs from predators by allowing them to blend into the ocean floor. By helping the crabs, the algae get a place to live.

The third type of relationship, +/O is where one organism benefits from one organism while neither benefitting nor harming the organism. Such relationships are called commensal relationships.

An example of this may be between barnacles and whales. Barnacles attach themselves to whales and use them as protection from predators.

Did you know that the difference between a parasite and a predator is the length of time in which they cause damage?

  • A parasite tends to have a longer effect on the host, draining resources and causing damage over time.
  • A predator, however, hunts and kills prey in a shorter period of time.
Both of these interactions are +/- relationships.

Population Ecology

Ecologists study ecology at six levels, increasing from small to large (see figure on levels of ecology). These are listed in the table below:

Table 1. Showing ecological hierarchy and the importance of each ecological level

Ecological Hierarchy
Definition
Ecological Importance
Individual
An individual is any organic, living system that functions as an individual entity.
Ecologists studying ecology at the organism level are mainly interested in how living organisms are adapted to live in their environment or habitat.
Population
A population is a group of living organisms of the same species that live together in the same area.
Ecologists who study populations are interested in the number of individuals in populations and how and why the size of populations changes over time.
Community
A biological community involves populations of different species living in the same area.
Ecologists study communities to find out why and how different populations interact with each other.
Ecosystem
An ecosystem includes all the living organisms in a biological community and their interactions with the environment.
Ecologists study ecosystems to find out how energy and nutrients are transferred amongst organisms in an ecosystem, as well as how different factors can affect the stability of ecosystems.
Biome
A biome is a life zone with communities of organisms with a particular adaptation to that area.
Ecologists study biomes to determine what kind of life inhabits a particular biome, like grasslands, deserts, lakes, etc. Abiotic conditions like water, air availability, and soil type help understand what kind of life exists in a biome.
Biosphere
The biosphere is the sum of all living organisms and ecosystems on Earth.
Ecologists study ecology at the biosphere level to explore migration (long-distance movement) patterns in animals, interactions between different ecosystems, as well as how global warming may affect different ecosystems.

Ecological succession is the process by which biotic and abiotic factors change over time in an ecosystem. There are two main types of ecological succession:

  1. Primary succession

  2. Secondary succession

Primary Succession

In primary succession, a newly formed rock is colonized by living organisms for the first time. The first species that colonize the region is called the pioneer species. These species are specially adapted to living in very hostile environments with little soil depth, water availability, or other resources.

An example of primary succession is the succession that occurs after a volcanic eruption.

Secondary Succession

In secondary succession, an area that was previously already colonized is recolonized. An example of when secondary succession occurs is after a wildfire. Secondary succession happens much faster than primary succession, as the area used to be colonized before the new species appeared.

As succession progresses, the following trends happen:

  • Soil depth increases

  • Water availability increases

  • Biodiversity increases

  • Soil quality improves

The following trends happen up until a climax community is reached.

The climax community is the point where both biotic and abiotic factors can coexist in a stable environment.

There are two types of climax communities, a climatic climax, and a biotic climax.

  • A climatic climax is reached when abiotic factors determine the climax of the community

  • A biotic climax is the climax community reached when biotic factors determine the climax.

Human Ecology

So far, we have talked about important ecological concepts in Biology, but ecology is a concept that is not exclusive to this subject. Scientists from other disciplines have also taken inspiration from how biologists study the interactions between organisms and their environment. An example of this is human ecology.

Human ecology is a concept used in the social sciences. It looks at how the quality of natural resources and the existence of other humans influence the collective behaviour of humans, giving rise to different social systems and structures.

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Ecology - Key takeaways

  • Ecology refers to how living organisms interact with each other and their physical environment.

  • A biotic factor is a living component of the environment that affects how living organisms are distributed.

  • An abiotic factor is a non-living component of the environment that affects how living organisms are distributed.

  • Ecologists study ecology mainly at six levels: individual, population, community, ecosystem, biome, and biosphere.

  • Succession is the process by which biotic and abiotic factors change over time. There are two types of ecological succession: primary and secondary succession.

Frequently Asked Questions about Ecology

Ecology is the branch of biology that helps us to understand everything from the surrounding organisms to the environment that they live in.

Ecological validity refers to the practicality of whether the results of a study can be applied in real life or no.

Ecology is the branch of biology that helps us to understand everything from the surrounding organisms to the environment that they live in.

Example of ecology may include the relationship between barnacles and whales. 

Barnacles attach themselves to whales and use them as protection from predators. 


The purpose of studying ecology is to determine why and how living organisms interact with each other. 

Final Ecology Quiz

Question

What is ecology? 

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Answer

Ecology is the branch of biology that helps us to understand everything from the surrounding organisms to the environment that they live in.

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Question

Ecologists seek to explain how organisms interact with each other in a particular environment 

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Answer

True

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Question

What is ecology? 

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Answer

Ecology is the branch of biology that helps us to understand everything from the surrounding organisms to the environment that they live in.

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Question

What are biotic factors? 

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Answer

Biotic factors are living things within an ecosystem. They also include organisms that were once-living.

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Question

What are abiotic factors? 

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Answer

Abiotic factors are factors that are non-living.

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Question

Which of the following is NOT an abiotic factor?

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Answer

Bacteria 

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Question

A parasitic relationship is 

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Answer

 A relationships where one organism benefits, whilst the other suffers.

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Question

Predator/prey interaction is an example of

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Answer

Parasitic relationship

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Question

What is mutualism? 

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Answer

When both organisms benefit from each other, it is called a mutualistic relationship. 

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What is a commensal relationship? 

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Answer

A relationship where one organism benefits from one organism while neither benefitting nor harming the organism.

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Question

Name one example of a commensal relationship 

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Answer

Barnacles and whales 

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Question

An individual is? 

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Answer

An individual is any organic, living system that functions as an individual entity.


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Question

A population is? 

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Answer

A population is a group of living organisms of the same species that live together in the same area. 

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What is a community? 

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Answer

A biological community involves populations of different species living in the same area. 

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Question

What is an ecosystem? 

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Answer

An ecosystem includes all the living organisms in a biological community and their interactions with the environment. 

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Question

What is a biome? 

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Answer

A biome is a life zone with communities of organisms with a particular adaptation to that a

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Question

What is a biosphere? 

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Answer

The biosphere is the sum of all living organisms and ecosystems on Earth. 

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Question

The first species that colonizes a region is called 

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Answer

Pioneer species 

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Question

Climax community is the point where both biotic and abiotic factor can NOT coexist in a stable environment.

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Answer

False 

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What are the two types of community climax? 

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Answer

Climatic climax and a biotic climax

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Question

Ecologists study ecology at 7 levels 

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Answer

False

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