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Key concepts

In this session we will focus on summarising what you need to know about:

  • Concept of an ecosystem
  • Structure and ecosystem function related to abiotic factors and biotic factors
  • Factors that influence terrestrial and aquatic primary production


Ecosystem - a community plus the physical environment that it occupies at a given time

Abiotic factors – non-living factors . Eg soil, air.

Biotic factors – living factors. Eg trees, insects.

Producer – organism that manufactures food by photosynthesis.

Herbivore – an organism that feeds on plants only.

Carnivore – an organism that feeds on animals only.

Omnivore – an organism that feeds on both plants and animals.

Saprotroph – an organism that feeds on dead and decaying matter. (fungi)

Decomposers – an organism that causes the decay of dead and dying organisms. (bacteria)

Scavenger – an organism that feeds on remains of animals.

Predator – an animal that hunts for its food.

Prey – an animal that is hunted and is food for the predator.

Food chain – a chain showing feeding relationships between organisms.


An ecosystem is a community of living organisms interacting with each other and their environment. Ecosystems occur in all sizes. A tidal pool, a pond, ariver, and a yellowwood forest are all examples of ecosystems. The living organisms (plants and animals) are referred to as biotic factors.The non-livingcomponents make up the abiotic factors. Organisms living in a particular ecosystem are adapted to the prevailing abiotic and biotic conditions.

Abiotic components

Abiotic factors may be grouped together as:

  • Physical / Climatic factors: sunlight, water, temperature and gases.
  • Edaphic factors: soil type, soil pH.
  • Physiographic factors: slope, aspect and altitude and latitude.

Climatic factors:


  • Light is a fundamental necessity.
  • The amount of sunlight an ecosystem receives is called insolation. This is critical for plant survival, especially in aquatic ecosystems. Light decreasesand water depth increases.
  • Amount of light changes from season to season.
  • In summer – days are longer, ecosystems gets more hours of sunlight than during short winter days.
  • The amount of sunlight affects other features of the ecosystem such as temperature, and the types of plants and animals that are found there.


  • Temperature increases with an increase in both latitude and altitude.
  • Temperature affects the rate at which photosynthesis, respiration and decomposition take place. The higher the temperature, the faster the processes.


  • Water is one of the most important factors in the ecosystem.
  • It is the main component of living cells and is essential for all living organisms.
  • About 80% of the human body and 90% of the plant body consists of water.
  • Water is evenly distributed over the earth.
  • It is abundant in aquatic ecosystems and least in deserts
  • Plants are adapted to the available amount of water in the following ways:
    • Xerophytes are plants that are able to live in dry habitats, or in regions with low annual rainfall. These plants are resistant to drought, have to cope withshortage of water, high temperatures and light intensities and dry warm winds. ie Cactus, Aloe
    • Hydrophytes are plants that are able to live entirely or partially in submerged water ot in very wet soil. These plants have to cope with a water surplus. ieWater lily, Water hyacinth
    • Mesophytes are plants that need an average, regular supply of water. ie Fruit trees, wheat

Questions & Answers

Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
why and for what was five kingdom of classification of organisms introduced
give the ans as fast as possible
Comment on the ozone depletion over the period of 1982 to 1996
Mpho Reply

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Source:  OpenStax, Siyavula: life sciences grade 10. OpenStax CNX. Apr 11, 2012 Download for free at http://cnx.org/content/col11410/1.3
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