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Introduction to Natural Ecosystems

Environmental degradation is a major issue of our time. A basic environmental building block is the ecosystem.

This article is intended to provide a resource for people who want to learn more about what ecosystems are and how they work. When I was working on a project on this same subject, I couldn't find any resources that offered a basic, thorough overview, so I decided to provide one myself!

Along the way, we'll look at:

  • Natural vs. artificial ecosystems
  • The different types of natural ecosystems
  • How an ecosystem functions
  • Human impacts

The Definition of "Ecosystem"

An ecosystem is a combination of two words: "ecological" and "system." Together, they describe the collection of biotic and abiotic (living and non-living) components and processes that comprise a defined subset of the biosphere. (The "biosphere" is the area of Earth that contains life, whether on the planet's surface or in the air.)

Natural vs. Artificial Ecosystems

  • Natural ecosystems may be terrestrial (such as a desert, forest, or meadow) or aquatic (a pond, river, or lake). A natural ecosystem is a biological environment that is found in nature (e.g. a forest) rather than created or altered by man (a farm).
  • Humans have modified some ecosystems for their own benefit. These are artificial ecosystems. They can be terrestrial (crop fields and gardens) or aquatic (aquariums, dams, and manmade ponds).

This article focuses on types of natural ecosystems, how they work, and what we can do to protect them.

Cultivated farms and gardens are types of artificial (human-made) ecosystems.

Cultivated farms and gardens are types of artificial (human-made) ecosystems.

Types of Natural Ecosystems

There are two main types of natural ecosystems, aquatic and terrestrial.

  • In aquatic ecosystems, organisms interact with water. (The prefix "aqua" means water.)
  • In terrestrial ecosystems, organisms interact with land. (The prefix "terra" means land.)
Aquatic ecosystems include oceans, rivers, and lakes.

Aquatic ecosystems include oceans, rivers, and lakes.

Aquatic Ecosystems

Aquatic ecosystems cover 71% of the earth's surface. There are three different varieties, defined by the kind of water in which the system's organisms interact.

  • Freshwater: This type includes lakes, rivers, ponds, streams, and some wetlands, and makes up the smallest percent of the earth's aquatic ecosystems.
  • Transitional communities: These are places where freshwater and saltwater come together, such as estuaries and some wetlands.
  • Marine: More than 70% of the earth is covered by marine (also called saltwater) ecosystems. These include shorelines, coral reefs, and open ocean.
Mountains, forests, deserts, and grasslands are types of terrestrial ecosystems. Text

Mountains, forests, deserts, and grasslands are types of terrestrial ecosystems. Text

Terrestrial Ecosystems

The four terrestrial ecosystems are classified by the type of land or terrestrial area in which organisms interact.

  • Forest: These ecosystems feature dense tree populations, and include boreal and tropical rain forests.
  • Desert: Deserts receive less than 25 cm of rainfall per year.
  • Grassland: These ecosystems include tropical savannas, temperate prairies, and arctic tundra.
  • Mountain: Mountain ecosystems include steep elevation changes between meadows, ravines, and peaks.

How Ecosystems Work

Energy and the Food Chain

Life is based on energy. On Earth, the sun is the primary source of energy. Plants turn sunlight into chemical energy through a process called photosynthesis.

Plants and trees are the energy producers. Herbivores (plant eaters) and carnivores (meat eaters) are energy consumers. They take in the chemical energy from sunlight through the food they eat. With that energy, they carry out all the processes of life.

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The food chain illustrates this energy relationship.

When an insect eats a plant, the insect takes in some of the sun's energy. If a bird eats the insect, the energy is transferred again. When a mammal, like a wildcat, eats the bird, then the energy is transferred one more time. This is how energy flows through an ecosystem.

Global Interdependency

All organisms and ecosystems on Earth are linked to one another. They are said to be "interdependent."

The principles of ecological interdependency are:

  • All species are dependent upon one another, either directly or indirectly.
  • When one is removed, whether through extinction or for human use, other species are affected, however indirectly.
  • The impact of one species' extinction can slowly cause the extinction of other species.

An example of these principles is the relationship between sea otters, kelp, and sea urchins. Each species depends on the others. Sea urchins eat kelp and sea otters eat sea urchins. Each of these species are harvested by humans, which can upset the balance among the three. When humans hunt sea otters, their populations decline. When the sea otters are killed or adapt by moving away, then sea urchins increase, potentially devouring entire stands of kelp. If humans harvest too many sea urchins, they can cause a decline in the sea otter populations that rely on those urchins. In response, the sea urchins can rebound in extreme numbers, denuding the kelp forest and discouraging sea otters from returning.

Human Impacts

Without human efforts to conserve natural resources, as well as recycling and reusing those we have already harvested, some of those resources will be gone forever. If we do not take care of our planet's delicate balance of ecosystems, then that will be the end of us and our world.

Ecosystems require balance to thrive. When one element increases or decreases, the ecosystem must adapt to the change. For example, if a meadow or forest ecosystem receives less moisture than is normal, the fruit-bearing plants may not produce as much food for native animals. In turn, those animals will reproduce at a lower rate.

Humans have had a disproportionate impact on the earth's ecosystems. The fertilizers used in farming, for example, often run off into streams and lakes, causing more algae than usual to grow. The increased algae kills off plants and animals in the lake, throwing the lake's ecosystem out of balance.

Human behavior has introduced pollution into the earth's ecosystems through the air, water, and soil. Also, our use of natural resources, especially fossil fuels, is altering the environment in serious and alarming ways.


luis on February 19, 2020:


matias cardoso on February 19, 2020:

very useful

Halemane Muralikrishna from South India on August 18, 2019:

Good ecology Hubpage. Very informative

Khushi on July 03, 2019:


Little Wolf on September 22, 2018:

This has been so helpful for school I can finally finish my extra credit presentation

hima on June 29, 2018:

This article is very helpful.Thank you so much.

anotida nyabadza on May 14, 2018:

Thanks you so much ,this information has helped me a lot in my studies

khamala Diana on April 04, 2018:

good work indeed clearly explain thanks

khan on November 25, 2017:

thanks uuu so much..this would be enough for my assighnment

l on November 14, 2017:

iam so lost and late if any one happened to stumble opon this comment please be very kind and help me findout how much ecosystems are there and please suscribe to my channel if i get 20 i wil make my first video o and my channel name on youtube is Eshauna M cQuilkin love ypu guys and thanks anyway if you dont but i will really love for you to help me to find my information for skool and to suscribe

maria lesiel on November 30, 2016:

this is a big help for me. it gives me additional knowledge on my studies especially on my exam... thanks a lot, more power and God bless...

JUBLES on November 03, 2016:


LOL on October 18, 2016:

thanks it works

Ayush Sinha on September 30, 2016:

It's very helpful thanx I got the appropriate answer for my exam

thaddaeus on June 18, 2016:

this is really helpful for my mid report

ashi on March 04, 2016:


fish on February 05, 2016:

this was h elp ful my essay thing said what are benefits of your ecosytem (desert) i put less than 25 cm of rain fall a year . :)

Bharath on November 12, 2015:

Thankyou for my exam

Jessy Villa on November 02, 2015:

Thank you very much ! It helps me to do my project !

mallika on July 07, 2015:

I like my environment some people destroy the nature like cutting the trees that should be avoided

H on May 24, 2015:

very nice note related environment. thanks lot.

abing sumpi kago on May 22, 2015:

Thank is really wonderful da way this article describe ecosystem. It help me a lot.....

bakhtawar on May 02, 2015:

I like it

Ronald sowan on April 08, 2015:

thank u 2 help me sir

rasika on February 23, 2015:

was very helpful osome

tanishka on February 08, 2015:

Its osum!

sham on November 12, 2014:

supreb yaar u

kumar on September 16, 2014:

not easy to understand

Rjade!!.. on August 04, 2014:

Gosh!! Science so hard

nisheet zehbi on May 18, 2014:

nyc effort. but can b even better and elaborated. thanx anyways :)

rose on May 13, 2014:

i hate science bad

subhash kushwaha on April 05, 2014:

Very very thank u sir

sneha on March 20, 2014:

this helped me for my exams thanks........sir

Divya Kushwaha on March 12, 2014:


ELLAJOY on March 06, 2014:


Banita sinha on January 29, 2014:

Thnx for the vital information.... it has helped me in making my bio project...

zohaib farman on November 16, 2013:

plz add ecosystem its component and its types in one topic

brealiana5901 on November 06, 2013:

Tnx a lot for the info...

its very helpful...

save mother earth!..people

JANANISELVARAJU on August 11, 2013:


BAHO BOTO on July 22, 2013:

ANU YUN.......!!1

abra on June 23, 2013:

tnx a lot

angel roshani on May 27, 2013:

stop!!! stop !!! stop!!! pollution ........

Sadaf on March 24, 2013:

You May Include the Types Of Artificial Ecosystem With Main Points Clearly.

Forthefuture (author) from India on January 06, 2013:

thanks to all for commenting on my article..thank you.

innocent nhimbe on August 20, 2012:

the natural ecosystem they have no cultivation occurs

isagani taruc on July 04, 2012:

thamk...for the info...VERY helpful...for me!!!!!!!!

pota on June 25, 2012:

d ko maintindihan men

vladimere on June 11, 2012:


joseph on June 10, 2012:


soumya pandey on May 29, 2012:


sne khoza on May 26, 2012:

I need help about,how the animals interect in forest ecosystem

lana on May 06, 2012:

1-forest ecosystem

2-narine ecosystem

3-natural ecosystem

4-tundra eosystem

5-fresh water ecosytem

6-marine ecosytem

priyanka vyas on April 17, 2012:

It's good but you can include that how an aquarium made up

Mellissa on March 28, 2012:

This was AWESOME!!!!!!

Sharanya on March 06, 2012:

Hi ppl this info really helped me a lot in making my biology project. Thank You once again and keep giving people information about environment and ecosystem. Thanks guys!

kathryn on February 07, 2012:

tnx..i realy appreciate this

kahot ano on January 30, 2012:

ang hirap hnd ko maintindihan hay.................... naku bkt ganito

aLekhYa on January 15, 2012:


wednesday on November 16, 2011:

Hi guys this info really helped me a lot in making my bio project. Thank You once again and keep giving people information about environment and ecosystem. Thank You

Forthefuture (author) from India on October 21, 2010:

thanks 2uesday and dramatis.....thank you very much...!!!!

Kera from USA on October 21, 2010:

Hi this is a very nice hub. I'm new here too and just thought I'd drop by to say hi. I saw your comment posted in the forums. Hi.

2uesday on October 21, 2010:

Even though I try care about the environment it feels like a drop in the ocean when I look around at the waste and pollution that is considered acceptable. I hope you enjoy writing here on HubPages and I think you have made a good start with this page.

Forthefuture (author) from India on October 21, 2010:

thanks..thank you very much..!!! sir..!! I would like to say you sir.! thanks again.! and about environment there are too many people ( I am also include) they just say to care of environment.! but don't do anything..! huh...

amorea13 on October 21, 2010:

Hi Forthefuture - I liked this hub and learned a lot - I am interested in this subject now though I spent a lot of years not bothering about it!Guess I'm like a lot of people!

I am also interested, however, in how 'big business' and government are NOT (not really) interested in truly doing anything which will interrupt their income-streams. They TALK about it but don't want to really lose their profits. It's down to the 'ordinary' person - as it always has been. Thanks for this hub - great.

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