Download L1 Biosphere

Global Systems
The Biosphere
Science 10
Science 10
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The biosphere...
Atmosphere
• is the thin layer of earth that supports life.
• is composed of three layers:
• lithosphere (solid portion)
• atmosphere (gas portion)
• hydrosphere (water portion)
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Atmosphere
Atmosphere
• About 80% nitrogen.
• About 20% oxygen.
• Less then 1% of other gases, such as CO ,
• In addition to gases, the atmosphere
contains:
• water vapour (usually considered part of
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the hydrosphere)
Ar, CH4, He.
• atmospheric dust (living and non-living)
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Atmosphere Layers
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Troposphere
• is the layer from the surface to an altitude
of about 10 km.
• Temperature decreases with altitude.
• Most of the mass of atmospheric gasses is
in the troposphere.
• Only layer that can support life (as we
know it).
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Stratosphere
Mesosphere
• is the layer from 10 km to about 50 km.
• Temperature increases with altitude.
• Most atmospheric O (g) is here, and
• is the layer from 50 km to about 80 km.
• Temperature decreases with altitude.
• Very thin atmosphere.
• Almost considered space.
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absorbs much solar radiation, especially UV
radiation (which causes sun burns and
melanoma).
• Human activity has reduced O (g) levels.
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Thermosphere
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Lithosphere
• is the layer from 80 km up.
• Temperature increases with altitude.
• Extremely thin atmosphere (essentially
• is the solid part of the earth’s crust.
• About 100 km thick.
• “Floats” on a semi-fluid mantle
• Is mostly warmed by the sun.
• Slight warming from the mantle.
none).
• Usually considered space.
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Lithosphere
Hydrosphere
• is all the water on earth.
• Almost all (about 97%) is salt water in the
oceans.
• The rest is fresh water in lakes, rivers, and
ice such as polar ice caps.
• Is mostly warmed by the sun.
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Components Interact
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Weather
• The various components of the biosphere,
• … is the conditions of temperature,
• Energy is transferred from one to the
• Example: Today the weather might be
the atmosphere, the lithosphere and the
hydrosphere all interact.
humidity, cloud cover, etc. at a particular
place at a particular time.
other.
cloudy and cold, while tomorrow it might
be warm and sunny.
• The interactions effect things such as
climate and weather.
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Climate
Your turn
• … is the average weather conditions over a
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long period of time.
• Time is usually at least 30 years.
• The weather today may be very different
than the weather one year ago, but the
climate is an average.
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Climate affects life
Climate affects life
• Average population density of
• NWT: about 0.04 people/km .
• Alberta: about 5 people/km .
• Indonesia: about 130 people/km .
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Warmer climates support more people.
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Alberta homes need to be able support a large
mass of snow on the roof.
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Tropical homes often need to withstand
extreme rainfall.
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People living in colder climates send more on
fuel for heating, and adequate clothing is
essential.
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Climate and adaptation
Climate and adaptation
• Different organisms have adapted to
different climates.
• Plants and animals in Alberta need to be
adapted to surviving long, cold winters.
• Plants and animals in Alberta need to be
adapted to surviving summers as well.
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Climate change
Weather vs. Climate
• is a change that occurs over long periods of
• Compare the average weather conditions
time (several decades at a minimum).
at a particular time of year (ie in April) to
previous years.
• This year might be very different than last
year, but that is weather not climate.
• But if those average conditions change over
decades, then the climate is changing.
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Evidence of change:
Past climate
• Anecdotal: reports from people about the
• Indirect evidence can tell us about climate
• Example: Farmers report that the growing
• Accurate temperature records have only
• Scientific: Data collected, often using
• Anecdotal and indirect evidence can give
weather and weather related events.
long ago, even time before people.
season starts earlier than it did years ago.
been kept for about 150 years.
instruments, that is accurate and unbiased.
clues to temperature hundreds of years
ago.
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Past climate
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Past climate
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Climate change
Climate change
• Evidence suggests that the average
temperature of the earth has risen quite
rapidly over the last 200 years.
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Climate change
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Climate change
• Climate is very complex, so determining
• Increase in atmospheric CO (g)
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why climate changes can be difficult.
concentration matches increase in average
global temperature.
• Atmospheric CO (g) concentration is
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considered the major cause.
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Climate change cause
Greenhouse Gas
• CO (g) tends to trap heat in the
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atmosphere.
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Melting ice caps
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Controversy
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