Download The Nitrogen Cycle - MsPetersensScienceScholars

March 14, 2013
Q-2 Pg.
Daily Goal: We will be able to explain why we
never run out of carbon.
Homework: Complete your daily carbon cycle log
Science Starter:
1. What does the Law of Conservation of Matter tell us?
2. What are at least 2 processes that illustrate the Law of
Conservation of Matter.
3. List two ways that carbon dioxide enters the
atmosphere.
4. List two organisms that contain carbon as a solid.

The Nitrogen
Cycle – the
series of
processes which
shows how
nitrogen is
recycled
throughout the
environment
protein

Nitrogen is
important because
it makes
 amino acids and
 nucleic acids.
Scholarly Word Alert!
DNA – deoxyribonucleic acid
 80% of the
Earth’s
atmosphere is
nitrogen gas
(N2), but plants
and animals can’t
use it!

Nitrogen gas (N2)
must be broken
down by lightning,
fire, or bacteria
before plants &
animals can use it.

There are four forms of Nitrogen.
1. Nitrogen gas (N2)
2. Nitrite (NO2-)
3. Nitrate (NO3- )
4. Ammonium ion (NH4+ )

Plants and animals can only take in nitrate
(NO3- ) and ammonia (NH4+ ).

Nitrogen Fixation
–when bacteria
“fix” nitrogen from
the air so the plants
can use it
 What forms of nitrogen can plants
and animals use?
Nitrate and Ammonia

Bacteria, that live
on the roots of
some plants,
change nitrogen
into ammonia, a
form of nitrogen
plants can use.

Denitrification –
is when bacteria
recycle nitrogen
back to the
atmosphere.

Ammonia in the soil
is converted back
into nitrogen gas
(N2)

Animals
(including
humans) get
nitrogen by
eating plants.

All nitrogen
obtained by
animals can be
traced back to
the eating of
plants.

Ammonification When plants and
animals die, their
bodies decompose
and release
ammonia back into
the soil for plants to
use.

What else happens when living things
decompose? Hint: Think of another cycle
that we know.


Burning fossil fuels and
wood contributes to a
large amount of nitric
oxide in the
atmosphere.
Nitric oxide can
combine with oxygen
gas to form acid
rain. The acid can
damage trees and kill
fish.

Acid rain speeds up another process that we
learned about that is part of another cycle.
What process does acid rain speed up?

Nitrogen Cycle Skill Builder
Understand? Take a stand!
•
•
•
•
I will read a question.
When you know the answer, stand up!
ONLY STAND UP IF YOU HAVE AN ANSWER
READY.
I will call on students who are standing. If you
answer correctly, you will get a point. If you
answer incorrectly, sit down.
Where do animals get nitrogen?
By eating plants which
have nitrogen!
So where do the plants get nitrogen?
From the soil!
What 3 ways can nitrogen gas be breakdown
so that plants can use it?
By lightning, bacteria
and fire!
What is it called when bacteria recycle
nitrogen back into the atmosphere?
Denitrification!
EXIT TICKET

Choose and answer 3 of the questions
on the following slide. Be sure to write
the QUESTION and the answer.
1.
Explain two ways that nitrogen gas in the
atmosphere is changed into nitrogen compounds
that plants can use.
2.
Compare and contrast the carbon cycle and the
nitrogen cycle. List at least one way that they are
similar AND one way that they are different.
3.
List at least two ways in which nitrogen can get into
the ground.
4.
Does the nitrogen cycle ever end? Explain your
answer in at least two complete sentences.
5.
Without bacteria, what would happen to the
nitrogen cycle? Explain why.