Transcript Lesson 3.3 Earth`s Spheres

CHAPTER
3
Earth’s Environmental Systems
Lesson 3.2 Systems in Environmental Science
Positive feedback loops can help
erosion turn a fertile field to desert in
just a few years.
Dust storm, Stratford
Texas, 1930s
Lesson 3.2 Systems in Environmental Science
Interacting Systems
• Inputs into Earth’s interconnected systems include energy,
information, and matter.
• Feedback loops regulate systems.
Negative feedback loop
• Negative feedback
loops: Result in
stabilization
of a system
• Positive feedback
loops: Result in a
system moving
to an extreme
Did You Know? Predator-prey cycles are negative feedback loops.
If prey populations rise, predator populations can rise in response,
causing prey populations to fall. Then predator populations may
decline, allowing prey populations to rise again, and so on.
Lesson 3.2 Systems in Environmental Science
Spheres of Function
Pg. 75 in book
draw out, label,
and color layers
• Earth can be divided into spheres that are defined
according to their location and function.
Lesson 3.3 Earth’s Spheres
The movement of Earth’s plates has
formed the deepest ocean trenches
and the highest mountains.
Lesson 3.3 Earth’s Spheres
The Geosphere
• Rocks and minerals on and below Earth’s surface:
• Crust: Thin, cool, rocky outer
“skin”
• Mantle: Very hot and mostly solid
• Core: Outer core is molten metal,
inner core is solid metal
Rock formation, Ouray National Wildlife Refuge, Utah
Lesson 3.3 Earth’s Spheres
Plate Tectonics
• Crust and mantle are divided
into:
• Lithosphere: Crust and
uppermost mantle; divided into
tectonic plates
• Asthenosphere: Soft middle
mantle; heated by outer core
• Lower mantle: Solid rock
• Convection currents in the
asthenosphere move tectonic
plates.
• Collisions and separations of
the plates result in landforms.
Volcano lava
Lesson 3.3 Earth’s Spheres
Tectonic Plates
• There are three major types of plate boundary:
• Divergent
• Transform
• Convergent
Lesson 3.3 Earth’s Spheres
Divergent and Transform Plate
Boundaries
• Divergent boundaries:
Rising magma pushes
plates apart.
• -mid ocean ridges
Divergent plate boundary
• Transform boundaries:
Plates slip and grind
alongside one another.
• -Earthquakes (San
Andreas Fault)
Transform plate boundary
Lesson 3.3 Earth’s Spheres
Convergent Plate Boundaries
• Plates collide, causing one of two things to happen:
• Subduction: One plate slides beneath another. (Mount St.
Helens in Washington)
• Mountain-building: Both plates are uplifted. (Himalayas)
Lesson 3.3 Earth’s Spheres
The Biosphere and Atmosphere
• Biosphere: The part of Earth in which living and
nonliving things interact
• Atmosphere: Contains the gases that organisms
need, such as oxygen; keeps Earth warm enough
to support life
Earth’s atmosphere, seen from space
Lesson 3.3 Earth’s Spheres
The Hydrosphere
• Consists of Earth’s water
Greenlaw Brook, Limestone, Maine
• Most of Earth’s water
(97.5%) is salt water.
• Only 0.5% of Earth’s
water is unfrozen fresh
water usable for drinking
or irrigation.
• Earth’s available fresh
water includes surface
water and ground water.
Did You Know? If it is depleted, groundwater
can take hundreds or even thousands of years
to recharge completely.
Lesson 3.3 Earth’s Spheres
The Water Cycle
Lesson 3.4 Biogeochemical Cycles
A carbon atom in your body today may have
been part of a blade of grass last year, or a
dinosaur bone millions of years ago.
Fossilized bones in a
Colorado dig.
Lesson 3.4 Biogeochemical Cycles
Nutrient Cycling
Did You Know? Organisms require
several dozen nutrients, such as nitrogen,
phosphorus, and carbon, to survive.
• Matter cycles through the
environment.
• Law of Conservation of MatterMatter can be transformed, but
cannot be created or destroyed.
• Nutrients, matter that organisms
require for life process, circulate
throughout the environment in
biogeochemical cycles.
• Macronutrients- needed in large
amounts
• Micronutrients in small amounts
Biogeochemical Cycles
• Nutrients circulate endlessly throughout the
environment in complex cycles
• Carbon, Oxygen, phosphorous Nitrogen.
• Water plays a part in all cycles
Lesson 3.4 Biogeochemical Cycles
The Carbon Cycle
Producers
Primary Producers- Organisms that
make their own food (Plants & Algae)
Photosynthesis- producers pull CO2 out
of the environment and combine it with
water in the presence of sunlight to
produce carbohydrates (sugar) and
oxygen
Consumers & Decomposers
• Consumers- organisms that must eat other organisms
to obtain nutrients
• Decomposers- organisms such as bacteria and fungi
that break down wastes and dead organisms
• Role in Carbon Cycle: Carbon in the producer may be
eaten by consumer or broken down by decomposer
and released back into environment
Cellular Respiration
• Process by which organisms use oxygen to release
chemical energy of sugars and release CO2 and
water.
• -Releases Carbon back into atmosphere
• -Opposite of Photosynthesis.
Carbon Sinks
• Not all carbon organisms take in is released it is used
for life processes
• Plants make so much carbon  Carbon sink
• Reservoir of a substance that accepts more of that
substance than it releases.
Carbon in Sediments
• Organisms die in water- settle on ground. Layers of
sediment accumulate above it.
• Soft tissue organisms can become fossil fuels over
long periods of time.
• Shells and skeletons- Sedimentary rocks (limestone)
TONS of Carbon
• -Releases Carbon through volcanic eruption and
erosion. Burning fossil Fuels.
Carbon in Oceans
• Second largest carbon reservoir
• Absorb carbon from atmosphere, runoff, undersea
volcanoes, and wastes and remains of organisms.
Human Impacts
• Extracting fossil fuels
• Burning them
• Cutting of forests and burning of forests to plant farm
fields
• **Producers cannot absorb enough carbon to keep up
with human activities.**
Missing Carbon Sink
• Scientists have measured the amount of CO2 that
humans have released into the atmosphere and
oceans, tons of carbon is unaccounted for.
• They believe it is taken up by the northern forests
Lesson 3.4 Biogeochemical Cycles
The Nitrogen Cycle
Nitrogen Cycle
• Makes up about 78 % of our atmosphere
• Essential ingredient in the proteins, DNA, RNA that
build our bodies
• Essential for plant growth
• Nitrogen gas cannot cycle out of the atmosphere
lithosphere, hydrosphere, and in organisms. Chemical changes need to occur- in order for it to
become useable
Nitrogen Fixation
• N2 or Nitrogen gas- Fixed into a usable form
(ammonia)
• Can occur through intense energy of lightning strike or
when air in the top layer of soil comes in contact with
particular nitrogen fixing bacteria.
• Nitrogen fixing bacteria- live freely in soil (soy beans,
legumes- Bacteria lives on roots)
Nitrification and Denitrification
• Some bacteria living in soil use ammonium ions from
nitrogen fixation or from the waste of decomposers to
perform nitrification
Nitrification- process where ammonium ions are
converted into nitrite ions and then into nitrate ions.
Plants can take up nitrate ions.
Denitrifiying bacteria- convert nitrates in soil or water
back to nitrogen gas.
Human Impacts
• Natural nitrogen fixation is slow so it limits flow of
nitrogen out of atmosphere and into biosphere
• Humans can fix nitrogen through the Haber-Bosch
process.  increases plant productivity.
Burning forests atmospheric nitrogen
Burning fossil fuels increase rate of nitric oxide
formation goes into atmosphere acid rain.
Fertilizer Eutrophication
Lesson 3.4 Biogeochemical Cycles
The Phosphorus Cycle
Phosphorous Cycle
• Involves mainly the lithosphere and the oceans
• Key component of cell membranes, DNA, RNA
• Most phosphorous is in rocks, soil, sediments, and
oceans
• Released by rocks being worn down by water or wind
• Low amount available
Organisms in the Phosphorous
Cycle
• Plants take up phosphorous through roots
• Consumers acquire it through water and other
organisms they eat
• Waste of consumers contains phosphorus and
decomposer return to the soil
Human Impacts
• Mining phosphorous fertilizer
• Release phosphorous rich waste water from houses
and businesses (Detergents- have it to improve
cleaning power).
• Runoff with wastewater and fertilizer go into
waterways
• Eutrophication occurs addition of phosphorus to
bodies of water can lead to an overgrowth of
producers(algae) Lead to low levels of oxygen in
water (hypoxia) as decomposers break down all dead
producers