Phys 102: Natural Systems

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Phys 102 Natural Systems
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The Atmosphere
Lecture 4
Phys 102 Natural Systems
The Atmosphere
The atmosphere is a mixture of nitrogen (78),
oxygen (21), and traces (remaining 1) of carbon
dioxide, argon, water vapor and other components.
Although the atmosphere is approximately 1,100 km
high, the stratosphere (10 to 50 km) and the
troposphere (less than 10 km) are the main
atmospheric interactors of the biosphere.
Vincent Conrad
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The Lithosphere
Lecture 4
Phys 102 Natural Systems
The Lithosphere
The lithosphere is the thin crust between the
mantle and the atmosphere. Although the
lithosphere is around 100 km thick, only 1 km of
it can be considered in interaction with the
biosphere.

• Main constituents are
• oxygen (47)
• silicon (28)
• aluminum (8)
• iron (5)
• calcium (4)
• sodium (3)
• potassium (3)
• magnesium (2)

The lithosphere is the main source of pollutants.
Some are naturally released through sources like
volcanic eruptions, while others like fossil
fuels are the result of artificial extraction and
combustion.
Vincent Conrad
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The Hydrosphere
Lecture 4
Phys 102 Natural Systems
The Hydrosphere
Water covers around 71 of the earth's surface
and is an important accumulator of pollutants.

• The hydrosphere is the accumulation of water in
  all its states (solid, liquid and gas) and the
  elements dissolved it in (sodium, magnesium,
  calcium, chloride and sulphate).
• 97 of the water forms the oceans
• 2 is ice (north and south poles)
• 1 forms rivers, lakes, ground water and
  atmospheric vapor.

The water cycle is essential to life on earth
(and elsewhere?)
Vincent Conrad
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The Hydrological Cycle
Lecture 4
Phys 102 Natural Systems
The Hydrological Cycle
All rivers run into the sea, yet the sea is not
full Unto the place from which rivers come,
thither they return again. Ecclesiastes 17
The hydrological cycle describes the circulation
of water as it evaporates, condenses and
precipitates.

• Water is essential to life (Earth is the only
  known place with lots of liquid water).
• 1404 million cubic km of water on Earth.
• The hydrological cycle constantly rejuvenates and
  purifies this water supply.

Vincent Conrad
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The Hydrological Cycle
Lecture 4
Phys 102 Natural Systems
The Hydrological Cycle
The cycle supplies fresh water to land masses,
and also helps maintain inhabitable climate on
earth by moderating temperature fluctuations.

• The cycle is dependent on phase changes of water
  -
• evaporation (liquid to gas below boiling)
• condensation (gas to liquid)
• sublimation (solid to gas)

From last weeks thermodynamics, why does this
help maintain temperature?
Humidity is the amount of water vapor in the air.
Hot air can hold more vapor the cold air and is
less dense. How does this help move water
around the planet?
Vincent Conrad
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The Biosphere
Lecture 4
Phys 102 Natural Systems
The Biosphere
The biosphere is the set of all living organisms.
It exists in a very complex set of
relationships with the atmosphere, hydrosphere
and lithosphere.

• Plants produce oxygen as waste, some of this
  makes ozone in the atmosphere, regulating the UV
  exposure on the lithosphere. (Average temperature
  on earth without the biosphere - 250 C)
• Plants take energy from the sun, converting it to
  structure - less extreme temperature
  fluctuations.

The ecosphere is the biosphere and the non-living
environment considered as one system. (Gaia)
Vincent Conrad
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Temperature Stability the Biosphere
Lecture 4
Phys 102 Natural Systems
Temperature Stability The Biosphere
Evapotranspiration (evaporation and transport) is
done by plants and has a major effect in certain
biomes.
Plants absorb ground water which evaporates from
the leaves, returning water to the hydrological
cycle.

• Evapotranspiration helps regulate the
  hydrological cycle. (75 of precipitation in
  rainforests)
• Ozone layer deflects UV, creating temperature
  gradient in the stratosphere. This effects
  convection in the troposphere, stabalising T.
  (Thanks plants)
• Life converts power from the sun into stored
  energy. (information?) - Fossil fuels are
  dangerous.

Biome A broad regional type of ecosystem
characterized by distinctive climate and soil
conditions, and a distinctive biological
community adapted to those conditions. e.g.
tropical rainforest, tundra,
Vincent Conrad
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Phys 102 Natural Systems
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Terms and Concepts
Lecture 4
Phys 102 Natural Systems
Terms and Concepts
Biodiversity the diversity of life on Earth,
including species diversity and genetic
diversity
Environment The surroundings which include all
the factors that affect the life of an organism.
These factors can be divided into two
categories Abiotic which includes all non-living
components of the environment such as
temperature, water, light etc... Biotic
which includes organisms and the products of
organisms (secretions wastes etc..) that are
components of the environment. Examples might
include predator or prey distributions.
Vincent Conrad
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Terms and Concepts
Lecture 4
Phys 102 Natural Systems
Terms and Concepts
Population a group of individuals of the same
species living and interacting in the same
geographic area.
Genetic diversity the diversity within a given
population, evidenced by different appearance
and behavior.
Habitat the place or space where a population (or
organism) lives.
Biological Community An area where different
species and populations interact -- e.g. a
wetland, a meadow, a cedar swamp, a hardwood
forest.
Ecosystem A community and its members (including
humans) interacting with each other and their
non-living (physical) environment. Ecosystems
vary in size and composition. The term may be
applied to a unit as large as the entire
ecosphere or to smaller divisions like the
Arctic or even small lakes.
Vincent Conrad
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Terms and Concepts
Lecture 4
Phys 102 Natural Systems
Terms and Concepts
Organism An organization of cells,
tissues, organs and body systems that combine to
create a living thing. (Bacteria to Gaia.)
Species Literally means kind. Refers to all
organisms that are genetically similar. A
practical definition is organisms that can breed
and produce viable off spring.
Species diversity the number of different species
and their relative abundance in different
habitats of the Earth.
Niche the functional role of an organism/species
in its community (e.g. insect feeder,
pollinator, etc)
Vincent Conrad