Cycles of nature.ppt elevate science grade 6

Cycles of nature.ppt elevate science grade 6

1. Cycles of NatureCycles of Nature

2. Water isn’t the only thing that flows Water isn’t the only thing that flows
between land and the atmospherebetween land and the atmosphere. .

MatterMatter in the form of nutrients also flow in the form of nutrients also flow
throughout the land and atmosphere.throughout the land and atmosphere.

The flow of this matter is known as The flow of this matter is known as cyclescycles..

The reason that we use the term cycles is The reason that we use the term cycles is
that matter in the universe is neither that matter in the universe is neither
created nor destroyed it merely changes created nor destroyed it merely changes
form. ( Law of conservation of matter)form. ( Law of conservation of matter)

3. Different types of cyclesDifferent types of cycles

There are many different types of There are many different types of
cycles in nature.cycles in nature.

From these cyclesFrom these cycles



The water cycleThe water cycle

The carbon cycleThe carbon cycle

The nitrogen cycleThe nitrogen cycle

4. Carbon CycleCarbon Cycle

Carbon and oxygen are critical for life on Earth, Carbon and oxygen are critical for life on Earth,
and their cycles are tied closely together.and their cycles are tied closely together.



Just as with water, these are both cycled so Just as with water, these are both cycled so
organisms always have a supply available.organisms always have a supply available.

The The carbon cyclecarbon cycle is the continuous movement of is the continuous movement of
carbon from the nonliving environment into living carbon from the nonliving environment into living
things and backthings and back..

5. 
The atmosphere; carbon dioxide gas The atmosphere; carbon dioxide gas
is one form of carbon in the air. is one form of carbon in the air.
Where is the Carbon?Where is the Carbon?

6. 
Photosynthesis- Plants use carbon Photosynthesis- Plants use carbon
dioxide in photosynthesis. In dioxide in photosynthesis. In
photosynthesis, the sun’s energy is photosynthesis, the sun’s energy is
used to make high-energy carbon used to make high-energy carbon
molecules. molecules.
Where is the Carbon?Where is the Carbon?

7. 
Wastes- Plants and animals release Wastes- Plants and animals release
carbon dioxide gas during carbon dioxide gas during
respiration.respiration.
Where is the Carbon?Where is the Carbon?

8. 
Organisms- use high-energy carbon Organisms- use high-energy carbon
molecules for growth. A large molecules for growth. A large
amount of the world’s carbon is amount of the world’s carbon is
contained in living things. contained in living things.
Where is the Carbon?Where is the Carbon?

9. Where is the Carbon?Where is the Carbon?

10. 
Fuel- Over millions of years, the Fuel- Over millions of years, the
remains of dead organisms are remains of dead organisms are
converted into fossil fuels, such as converted into fossil fuels, such as
coal, gas, and oil. These fuels coal, gas, and oil. These fuels
contain carbon molecules. contain carbon molecules.
Where is the Carbon?Where is the Carbon?

11. 
Pollution- combustion of fossil fuels Pollution- combustion of fossil fuels
and wood releases carbon dioxide. and wood releases carbon dioxide.
Where is the Carbon?Where is the Carbon?

12. 
Starting with Starting with
atmospheric carbon atmospheric carbon
dioxide, the carbon cycle dioxide, the carbon cycle
begins with plants begins with plants
absorbing COabsorbing CO
22 and and
converting into usable converting into usable
sugars and starches.sugars and starches.

This process is known as This process is known as
photosynthesisphotosynthesis..
The Carbon CycleThe Carbon Cycle

13. 
Animals then eat Animals then eat
these plants.these plants.

They break down They break down
the sugars & the sugars &
starches made by starches made by
plants and release plants and release
energy. energy.

In the process, they In the process, they
release COrelease CO
22 back back
into the into the
atmosphere.atmosphere.

This process is This process is
called called cellular cellular
respirationrespiration..
The Carbon CycleThe Carbon Cycle

14. The Carbon CycleThe Carbon Cycle

All life, plants, animals & everything else, All life, plants, animals & everything else,
eventually dies. eventually dies.

When it does it is broken down , decays, and When it does it is broken down , decays, and
collects as fossil fuels.collects as fossil fuels.
•Fossil fuels, like
oil and gasoline,
accumulate after
millions of years
of this process of
death and decay.

15. The Carbon CycleThe Carbon Cycle

The burning of The burning of
this fuel, called this fuel, called
combustioncombustion, ,
also releases also releases
carbon dioxide carbon dioxide
back into the back into the
atmosphere.atmosphere.

16. COMBUSTION
Man also
plays a role.
We are
responsible
for burning
fossil fuels,
eating,
releasing
carbon
dioxide, and
dying.
These all
contribute to
the cycling of
carbon.
People contribution to People contribution to
carbon cyclecarbon cycle

17. Nitrogen CycleNitrogen Cycle

Nitrogen, another essential element, must also be Nitrogen, another essential element, must also be
cycled.cycled.

Importance of NitrogenImportance of Nitrogen
•To make chlorophyll in plants.To make chlorophyll in plants.
•To make protein and DNA in animals.To make protein and DNA in animals.

18. Nitrogen CycleNitrogen Cycle

Nitrogen, another essential element, must also be Nitrogen, another essential element, must also be
cycled.cycled.

The nitrogen cycle is all about getting The nitrogen cycle is all about getting
the nitrogen in the atmosphere into the nitrogen in the atmosphere into
forms that can be used by organisms. forms that can be used by organisms.

The The nitrogen cyclenitrogen cycle is the process in which is the process in which
nitrogen circulates among the air, soil, water, and nitrogen circulates among the air, soil, water, and
organisms in an ecosystemorganisms in an ecosystem..

19. How nitrogen existsHow nitrogen exists

Free formFree form, Nitrogen , Nitrogen
makes up about 78% of makes up about 78% of
our atmosphere. (Nour atmosphere. (N 22))

It is not usable to It is not usable to
humans and animals in humans and animals in
this form. However, it this form. However, it
takes takes lightninglightning and and
certain certain bacteriabacteria to to
convert nitrogen into a convert nitrogen into a
usable form. usable form.

20. How nitrogen existsHow nitrogen exists

FixedFixed form in the soil. form in the soil.

Free Nitrogen is fixed into the soil by Free Nitrogen is fixed into the soil by
lighteninglightening or or bacteriabacteria through a through a
process called process called Nitrogen fixationNitrogen fixation. .

21. •Nitrogen-fixing bacteria
live in the soil and on the
roots of some plants.
•In a process called nitrogen
fixation, bacteria convert nitrogen
gas, N
2
, into ammonia, NH
3
.
•N
2
 Nitrogen Fixation (Bacteria)  NH
3
Nitrogen CycleNitrogen Cycle
How
atmospheric
nitrogen gets
into the soil so it
can be accessed
by living things.

22. 
Also nitrogen gets into the soil Also nitrogen gets into the soil
through adding through adding fertilizersfertilizers for plants for plants
that supply plants with nitrogen.that supply plants with nitrogen.

23. •During
ammonification,
nitrogen from
animal waste or
decaying bodies
is returned to
the soil as
ammonia by
bacteria and
decomposers.
Nitrogen CycleNitrogen Cycle
How
atmospheric
nitrogen gets
into the soil so it
can be accessed
by living things.

24. •During
nitrification,
ammonia, NH
3
, is
converted to
nitrite and then
nitrate NO
3
.
Nitrogen CycleNitrogen Cycle

25. •Assimilation is the
process in which
plants absorb
nitrogen. When an
animal eats a plant,
nitrogen compounds
become part of the
animal’s body.
Nitrogen CycleNitrogen Cycle
Forms of
nitrogen that
can be
accessed by
living things

26. •During denitrification,
nitrate, NO
3
, is changed
to nitrogen gas, N
2
, which
returns to the
atmosphere.
Nitrogen CycleNitrogen Cycle

27. Nitrogen Cycle: On your handouts, label the parts Nitrogen Cycle: On your handouts, label the parts
of the cycle.of the cycle.

28. Nitrogen CycleNitrogen Cycle

30. How humans affect Nitrogen cycleHow humans affect Nitrogen cycle

Humans contribute extra Nitrogen in the cycle Humans contribute extra Nitrogen in the cycle
due to due to fertilizers fertilizers and and animal waste animal waste (hog (hog
lagoons) that runoff into in the lakes and rivers. lagoons) that runoff into in the lakes and rivers.

••Extra Nitrogen in the groundwater can Extra Nitrogen in the groundwater can
interfere with blood/oxygen levels and cause interfere with blood/oxygen levels and cause
blue-baby syndrome. blue-baby syndrome.

••Excess Nitrogen can cause Eutrophication Excess Nitrogen can cause Eutrophication
which causes aquatic life to die due to the low which causes aquatic life to die due to the low
levels of oxygen. (fish kills) levels of oxygen. (fish kills)

••High levels of ammonia is also toxic to animals High levels of ammonia is also toxic to animals

31. Role of decomposersRole of decomposers
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32. Role of decomposersRole of decomposers
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