Systems
A Level Geography - Earth Life Support Systems -correct answer_A Level Geography -
Earth Life Support Systems How is water important in supporting life? -correct
answer_- Water provides a medium that allows organic molecules to mix and form
more complex structures. - Water helps to create benign thermal conditions on Earth.
For example, oceans (occupy 71% of Earth's surface) moderate temperatures by
absorbing heat, storing it and releasing it slowly. - Clouds made up of tiny water
droplets and ice crystals reflect a fifth of incoming solar radiation and lower surface
temperatures. - Water vapour absorbs long-wave radiation from the Earth helping to
maintain average global temperatures. What enables water to exist in liquid form on
Earth? -correct answer_The ubiquity of liquid water on Earth is due to the distance of
the Earth from the Sun: it lies in the 'Goldilocks zone', which is perfect for water to
exist in liquid form. How is water used for flora, fauna and people? -correct answer_-
Water makes up 65-95% of all living organisms and is crucial to their growth,
reproduction and other metabolic functions. - Plants need water for photosynthesis,
respiration and transpiration - Plants also require water to maintain rigidity and to
transport mineral nutrients from the soil. - In people and animals, water is the
medium for all chemical reactions in the body including the circulation of oxygen and
nutrients - Transpiration of water from leaf surfaces by evaporation cools plants. -
Sweating is the cooling process in humans - Water is also used to generate electricity,
irrigate crops, provide recreational facilities and satisfy public demand. It is also used
in food manufacturing, brewing, paper making and steel making. How is carbon
important for life on Earth? -correct answer_- Large molecules of carbon atoms such
as proteins, carbohydrates and nucleic acids are essential in life - Fossil fuels such as
coal, oil and natural gas power the global economy. - Oil is also used as a raw material
in the manufacture of products ranging from plastics to paint and synthetic fabrics. -
Agricultural crops and forest trees also store large amounts of carbon available for
human use as food, timber, paper, textiles and many other products. On a global scale,
in what system do carbon and water flow? -correct answer_In a closed system What
areas do carbon and water flow between? -correct answer_The atmosphere, oceans,
land, and biosphere How long does the cycling of water and carbon take? -correct
answer_Days to millions of years At the macro-scale, what three stores does the global
water cycle consist of? -correct answer_The atmosphere, oceans and land By what
processes does water move between stores? -correct answer_Precipitation,
evapotranspiration, run-off and groundwater flow How much carbon does long-term
storage in sedimentary rocks hold? -correct answer_99.9% of carbon on Earth What
are he main pathways that carbon takes when it moves between stores? -correct
answer_Photosynthesis, respiration, oxidation (decomposition and combustion) and
weathering What are systems? -correct answer_Systems are groups of objects and the
relationships that bind the objects together Define closed system -correct answer_A
system in which only energy can cross boundaries of the global water cycle and
carbon cycle. What are open systems? -correct answer_Where materials as well as the
Sun's energy cross system boundaries. Happens at smaller scales, e.g. drainage basin
or forest ecosystem What is a reservoir? -correct answer_A lake that stores water for
human use. How much water do the oceans contain? -correct answer_1,370,000 km
cubed * 10cubed What percentage of global water is in the oceans? -correct
answer_97% How much water does polar ice and glaciers contain? -correct
answer_29,000 km cubed * 10 cubed What percentage of global water is in polar ice
and glaciers? -correct answer_2% How much water does groundwater (aquifers)
contain? -correct answer_9,500 km cubed * 10 cubed What percentage of global water
is in groundwater? -correct answer_0.7% How much water do lakes contain? -correct
answer_125 What percentage of global water is in lakes? -correct answer_0.01% How
much water do soils contain? -correct answer_65 What percentage of global water is in
soils? -correct answer_0.005% How much water does the atmosphere contain?
-correct answer_13 What percentage of global water is in the atmosphere? -correct
, answer_0.001 How much water do rivers contain? -correct answer_1.7 What
percentage of global water is in rivers? -correct answer_0.0001% How much water
does the biosphere contain? -correct answer_0.6 What percentage of global water is in
the biosphere? -correct answer_0.00004% According to the US Geological Survey
(USGS), how much water does the global water cycle circulate every year? -correct
answer_Estimated 505,000 km cubed of water is circulated in a year Describe the
inputs and outputs of water -correct answer_- Inputs of water to the atmosphere
include water vapour evaporated from the oceans, soils, lakes and rivers, and vapour
transpired through the leaves of plants. Together these processes are known as
evapotranspiration. - Moisture leaves the atmosphere as precipitation (i.e. rain, snow,
hail, etc.) and condensation (e.g. fog). Ice sheets, glaciers and snowfields release water
by ablation (melting and sublimation) - Precipitation and meltwater drain from the
land surface as run-off into rivers. Most rivers flow to the oceans through some, in
continental drylands like southwest USA, drain to inland basins. A large part of water
falling as precipitation on the land reaches rivers only after infiltrating and flowing
through the soil. - After infiltrating the soil, water under gravity may percolate into
permeable rocks or aquifers. This groundwater eventually reaches the surface as
springs or seepage and contributes to run-off. What are the stores of carbon? -correct
answer_- The Atmosphere - The oceans - Carbonate rocks - Fossil fuels - Plants - Soils
How much carbon does the atmosphere store? -correct answer_600 billion tonnes
How much carbon do the oceans store? -correct answer_38,700 billion tonnes How
much carbon do sedimentary rocks store? -correct answer_60,000-100,000,000
billion tonnes How much carbon do sea floor sediments store? -correct answer_6,000
billion tonnes How much carbon do fossil fuels store? -correct answer_4,130 billion
tonnes How much carbon do land plants store? -correct answer_560 billion tonnes
How much carbon do soils/peat store? -correct answer_2,300 billion tonnes What are
the two strands of the carbon cycle? -correct answer_The slow cycle and the fast cycle.
How does carbon stored in oceans operate in the slow carbon cycle? -correct answer_-
Carbon stored in rocks, sea-floor sediments and fossil fuels is locked away for millions
of years. - The total amount of carbon circulated by this cycle is between ten and 100
million tonnes a year. - Carbon dioxide diffuses from the atmosphere into the oceans
where marine organisms, such as clams and corals, make their shells and skeletons
by fixing dissolved carbon together with calcium to form calcium carbonate. On death,
the remains of these organisms sink to the ocean floor. There they accumulate and
over millions of years, heat and pressure convert them to carbon-rich sedimentary
rocks. What role do sedimentary rocks have in the slow carbon cycle? -correct
answer_- Typical residence times for carbon held in rocks are around 150 million
years, - Some carbon-rich sedimentary rocks, subducted into the upper mantle at
tectonic plate boundaries, are vented to the atmosphere in volcanic eruptions. Other
exposed at or near the surface by erosion and tectonic movements are attacked by
chemical weathering. What role does chemical weathering have on the slow carbon
cycle? -correct answer_Chemical weathering processes such as carbonation are the
result of precipitation charged with carbon dioxide from the atmosphere, which forms
a weak acid. The acid attacks carbonate minerals in rocks, releasing carbon dioxide to
the atmosphere, and in dissolved form to streams, rivers and oceans. What role does
partly decomposed organic material have on the slow carbon cycle? -correct
answer_On land, partly decomposed organic material may be buried beneath younger
sediments to form carbonaceous rocks such as coal, lignite, oil and natural gas. Like
deep-ocean sediments, these fossil fuels act as carbon sinks that endure for millions
of years. How much faster in the fast carbon cycle than the slow carbon cycle? -correct
answer_Carbon circulates most rapidly between the atmosphere, the oceans, living
organisms (biosphere) and soils. These transfers are between 10 and 1000 times
faster than those in the slow carbon cycle. What role do phytoplankton play in the fast
carbon cycle? -correct answer_- Land plants and microscopic phytoplankton in the
oceans are the key components of the fast cycle. - Through photosynthesis they
absorb carbon dioxide from the atmosphere and combine it with water to make
carbohydrates. Describe respiration in the fast carbon cycle -correct
answer_Respiration by plants and animals is the opposite process and results in the
release of carbon dioxide Describe decomposition in the fast carbon cycle -correct