Download The environment is made up of chemicals that

The environment is
made up of chemicals
that can support or
harm living things
• Water is one of the
chemicals that is essential for
life.
 Life-supporting substances
dissolve in water and are
transported to all parts of
your body
 Water carries waste
materials to your kidneys
for removal
 Gases such as oxygen
dissolve in the water
The Nitrogen Cycle
Plants cannot use this “free” nitrogen
directly. It has to be “fixed” in compounds
with other elements
Nitrogen Fixation is the process of
changing free nitrogen so that nitrogen
atoms can combine with other elements to
form compounds
Certain types of bacteria do most of the
nitrogen fixation in the soil
Some located in the root nodules of specific
types of plants (beans, clover and alfalfa)
Lightning also converts nitrogen in the air to
nitrogen compounds
Step 2
Animals eat plants;
use the nitrogen in the compounds to make more complex
substances
Decomposers break down large nitrogen-containing molecules in dead
organisms and animal waste to simpler nitrogen compounds in the soil
The nitrogen can move from organisms and back to the soil several
times
Eventually some nitrogen-containing compounds are broken down further
by other bacteria (denitrifying bacteria)
Released back into the air
The
Nitrogen
Cycle
video
Fertilizer
• Is a substance that
enriches soil so that
plants will grow
better
• Described by the
major nutrient
element they contain
(Nitrogen,
phosphorus and
potassium)
“Up, Down, all around”
• First number helps the
plant grow up
• Second number helps
roots and produce
flowers
• Third number helps
overall heath of plant ,
helps build strong cells
Pesticides
– Chemicals that kill pests
Herbicides
– kill or control weeds
Insecticides
– Kill or control insects
Fungicides
– Kill fungi
Waste-waters
 Septic Tanks (Rural)
 Underground container
 Bacterial break down
the organic material
 Moved out into the soil
• Sewage Treatment
Plant (Urban)
 Treats wastes from
homes,
businesses,
industries and
institutions
 Also may treat
street drain waters
 Released into
rivers and lakes
 May contain
nitrogen and
phosphorus