Global Geography 12
Chapter 3 Notes # 1
Why is there life on Earth? Because of the Goldilocks Zone
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Earth’s life-sustaining conditions are possible because of its position in the _________________
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It is not too _____and not too ________ . If the Earth was any closer or further away from the
Sun, the planet could not support ________________________
What are other reasons why there is life on planet Earth?
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Earth’s rotation on its axis and orbit around the ________ helps distribute heat evenly around
the planet
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Earth’s _________________ field protects the planet from deadly radiation and particles
Earth’s gravitational field holds the atmosphere in place preventing oxygen, nitrogen, and carbon
dioxide from escaping into space
What are the Four Conditions for Life?
1. Stable Temperature Range
2. The Importance of Water
3. The Importance of Gases
4. The Role of the Atmosphere
Stable Temperature Range
stable temperature range (-50 to about +50 degrees Celsius) allows life to ___________ – the average
temperature has been between 10-20 degrees Celsius for _________billion years
The Greenhouse effect
The greenhouse effect allows for___________ in the atmosphere (carbon and water vapor) to be reradiated ____________ to Earth
Without proper water and carbon, the earth would be __________ degrees C.
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Plants play a significant role in creating a stable temperature through releasing ______________
and _____________________by the processes of photosynthesis and transpiration
Dark areas of vegetation absorb __________________ from the sun’s rays and limit the albedo effect –
heat being reflected back into space
Photosynthesis
The Importance of Water
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First water likely came from ________________ activity – water collected on the cooling surface
and as vapour in the atmosphere creating the water cycle
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Biologists believe earth first began in the oceans – blue-green algae
Oceans cover ___________ of the Earth – absorbs heat and distributes it around the world and controls
our ______________ patterns and climates
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Helps distributes nutrients to _______________and other organisms
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No living thing consists of less than ____________ water
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Water is the metabolizing agent that allows _________________ and ________________to
dissolve minerals and nutrients to create energy
The Importance of Gases
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_____ nitrogen, ______ oxygen, ______carbon dioxide - quite different than other planets in
the solar system
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The _________ have removed most of the carbon dioxide that originally existed and produced
lots of oxygen
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Without life on earth, carbon dioxide would _________________
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The production of carbohydrates, fats, and proteins require oxygen, carbon, and nitrogen atoms
from the atmosphere, and hydrogen from water
The Importance of the Atmosphere
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Layer of gases about _______________ kms thick – very thin compared to size of Earth
Helps maintain a consistent temperature
Shields earth from collisions with cosmic particles (meteors)
Oxygen levels at _______ allow for life, if they drop, animal life would not be possible, if it
exceeds _________ , most plants would be consumed by fire
Oxygen is produced by ___________ and consumed by ________________and the burning of
plants and fossil fuels
Atmosphere is thick enough to protect living things from the sun’s ultraviolet _______________
The 4 Speres
1. Lithosphere – earth’s__________ (soil, rocks, and minerals)
2. Hydrosphere – earth’s ____________
3. Atmosphere – the ______________ in the air
4. Biosphere – all _________________ (plants, bacteria, animals)
BIOSPHERE
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Encompasses all living organisms including __________________
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Divided into separate but interdependent units called _________________ – well defined
habitats hosting systems of interacting organisms
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Nutrient Cycle - Continuation of life depends on the constant recycling of chemical ingredients
called ___________________ (Example: plants and animals die and decompose)
Biosphere - The Carbon Cycle
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The movement of carbon from the atmosphere into plants, animals, and the __________ and
then back again
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Plants take carbon dioxide from the atmosphere to produce food through photosynthesis and
release _____________________ – animals breath oxygen and eat plants
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Dead animals and plants decay and return ___________________ to cycle
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Over production of carbon dioxide from factories and burning rainforests causes ______ change
Biosphere – The Nitrogen Cycle
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Most powerful element in the Earth’s _______________________
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Microscopic bacteria live on the roots of certain plants known as _______________ and
converts nitrogen to ammonia and nitrates which the plant absorbs and converts to
__________________ – food production
Biosphere - The Oxygen Cycle
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Oxygen produced by the respiration of plants – ________ of oxygen used is replaced by algae in
oceans
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__________________ created by photosynthesis
Biosphere –The Water Cycle
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Water must be _________________ through the atmosphere and back to the Earth’s surface
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Most from evaporation – some from _______________________; water drawn by plants and
released through their leaves
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Groundwater dissolves nutrients in the soil