2. Cycles of Elements
Nutrients (water, nitrogen, carbon) are cycled through
the Earth in cycles called the BIOGEOCHEMICAL
CYCLES.
Law of Conservation of Mass
Matter cannot be created or destroyed in chemical
reactions it simply changes forms
No new sources of matter on Earth instead it continuously
cycles through
Matter simply changes in the way that the elements are
bonded together
4. 5 Main Processes of the Water
Cycle
1) Evaporation: Water turning from a
liquid into a gas.
Liquid water from
oceans, lakes or other
bodies of water,
changes into water
vapor (gas) and is
released in the
Water Cycle
5. 2) Transpiration:
when liquid water in
plants changes into
water vapor (gas) and
is released into the
atmosphere
Part of photosynthesis
3) Condensation:
water vapor (gas)
changes into liquid
•Ex. Cloud formation,
dew
6. 4) Precipitation: when
water returns to the
Earth’s surface
Water droplets get too
large, they fall out of the
air.
Ex. Rain, snow, hail
5)Runoff- water moving
from a higher elevation
(mountains, etc.) to a
lower elevation (oceans,
lakes, seas, etc.)
8. II. Nitrogen Cycle
Nitrogen gas (N2) is naturally found
in the atmosphere
It is the most abundant gas in our
atmosphere.
N2 is
unusable to
most living
things
9. Some bacteria and lightning are able to
change nitrogen gas (N2) into chemicals
called nitrates (NO3), which are usable by
plants.
16. Carbon is found in the atmosphere as
Carbon Dioxide (CO2)
CO2 is used by plants during
photosynthesis to make food and give
off O2.
17. Animals eat food (plants) for energy.
During cellular respiration (that takes place
in plants and animals), the organism takes in
O2 gives off CO2.
This releases the CO2 back into the
atmosphere (respiration).
18. Some carbon is trapped in dead creatures
and changed into a fossil fuel (coal or oil).
The decomposition of dead organisms
releases carbon back to the atmosphere.
19. Burning of plant material or fossil
fuels, also returns carbon as CO2
back to the atmosphere.
21. Greenhouse Effect
Naturally occurring gasses in the Earth’s
atmosphere that trap heat. They keep the Earth’s
temperature about 60° warmer than it would be
otherwise.
Human Impact:
Change: Increased level of greenhouse gases (such
as CO2, methane, & water vapor)
Cause: Burning of fossil fuels and deforestation
Effect: Global warming
22.
23. Ozone Layer
The ozone layer is a naturally occurring layer of the
stratosphere that absorbs large amounts of
ultraviolet rays.
Human Impact:
Change: Reduction of ozone (O3) detected near
poles
Cause: Release of chlorofluorocarbons (CFC) that
catalyze reactions with ozone molecules
Effect: Increased ultraviolet radiation at the Earth’s
surface
Notes de l'éditeur
Use this slide to discuss cycle, students don’t need to write down yet
Draw a stick-figure example of this slide on the board. Add fossilization and skip detritus. Separate trees burning and burning of fossil fuels.