3.4 - Cycles of Matter - Lake Central High School

3.4 - Cycles of Matter

 Energy travels in a one-way flow through the trophic levels of a food chain.

 Matter, unlike energy, is recycled within and between ecosystems.

 Living organisms are composed mostly of four elements:
- oxygen
- carbon
- hydrogen
- nitrogen
(there are a few other elements, such as phosphorus & sulfur)

 These elements are the basis of life’s most important compounds:
- water
- carbohydrates
- lipids
- nucleic acids
- proteins

 Organisms cannot make these elements and do not use them up – they are recycled
through the biosphere

 Matter can cycle through the biosphere because biological systems do not use up matter;
they only change it.

 Matter is passed from one organism to another and from one part of the biosphere to
another part through biogeochemical cycles

 These cycles connect biological, geological, and chemical processes.

The Water Cycle

 Living things require water to survive.
- used to carry out many important and complex chemical reactions in organisms
- carries nutrients to varies parts of organisms and carries waste away for different parts
of organisms

 The water found within your body has been used, and re-used by organisms throughout
the history of Earth.

 Water cycles between the ocean, atmosphere, and land.

Important terms used in the Water Cycle:
 EVAPORATION: process by which water changes from a liquid to a vapor

 TRANSPIRATION: the evaporation of water from plant leaves.

 CONDENSATION: Condensation is the process in which water vapor in the air is changed into
liquid water. Condensation is crucial to the water cycle because it is responsible for the
formation of clouds.

 PRECIPITATION: when water in the atmosphere condenses and falls to Earth’s surface.
Examples are rain, freezing rain, sleet, snow, or hail

 RUNOFF: precipitation that flows along Earth’s surface. When rain hits saturated or
impervious ground(such as blacktop or concrete) it begins to flow overland downhill until it
enters streams, rivers, lakes and oceans.

1. Water evaporates from lakes and ocean surfaces. The evaporated water
condenses and form clouds that may travel over vast distances.

2. Precipitation as mist, rain, snow or ice falls over the land and the sea.

3. Some groundwater may emerge as a spring or may enter lakes and
oceans.

4. Some water sinks into the ground, becoming part of the groundwater.

5. Plants and animals use water and return it to the environment through
transpiration, perspiration, or urination.

6. Surface water runoff enters streams, rivers, lakes and oceans.

The Carbon Cycle

 Carbon is an important element to living things.
 Although the most abundant substance in organisms is water, the second

most abundant substance is carbon.


 During photosynthesis, plants combine carbon dioxide from the air and

hydrogen from water to make carbohydrates.

o Some of these carbohydrates are stored in the tissues of the
plant.

o Others are used by the plant for energy.

 When that plant is eaten, the cells of the animal(or human)break down the
plant's tissues during digestion.

o This releases the stored carbon and other nutrients into the
animal's system.

 As the animal breathes out (exhales), carbon dioxide is released into the air
(atmosphere) and the cycle can begin again. This is known as respiration.

 Respiration is not the only way carbon makes it into the air (atmosphere).
o Carbon and/or carbon dioxide is also released when dead
plants and animals are decomposed
o Human Activity such as the burning of fossil fuels

 When plants and animals die, much of their carbon is returned to the
atmosphere as the organisms decompose.

 Every so often, a plant or animal does not decompose right away.

o Trapped in locations where decomposition cannot take place,
most commonly at the bottom of oceans and seas

o life forms become buried by sand and becomes fossilized in rock
o Plants that die and are buried may turn into fossil fuels made of

carbon such as coal

Human Disturbance to the Cycle

 As rocks weather, this carbon is slowly released back into the atmosphere,
creating a balance
o for millions of years the amount being released by
weathering rocks was almost perfectly balanced

 This important balance has been altered significantly in the past century, as
humans have begun using fossil fuels to produce energy.

 By releasing more carbon into the atmosphere than is being locked up, we
risk causing damage to the delicate carbon cycle.

 In the atmosphere, carbon is attached to some oxygen in a gas called
carbon dioxide.
o Carbon dioxide is a greenhouse gas and traps heat in
the atmosphere
o Without it and other greenhouse gases, Earth would be
a frozen world.
o humans have burned so much fuel that there is about
30% more CarbonDioxide in the air today than there
was about 150 years ago.
o As a result, Earth is becoming a warmer place

THE CARBON CYCLE

Important terms used in the Carbon Cycle:
 PHOTOSYNTHESIS: process used by plants and other autotrophs to capture light
energy and use it to power chemical reactions that convert carbon dioxide
and water into oxygen and energy-rich carbohydrates such as sugars and
starches.
 GREENHOUSE EFFECT: process in which certain gases (carbon dioxide,
methane, water vapor) trap sunlight energy in Earth’s atmosphere as heat
 CARBONATE ROCK: class of sedimentary rock composed primarily of carbonate
minerals.
 CELLULAR RESPIRATION: process that releases energy by breaking down glucose
and other food molecules in the presence of Oxygen
 CARBOHYDRATE: compound made up of Carbon, Hydrogen, and Oxygen
atoms; type of nutrient that is the major source of energy

Nitrogen Cycle

 80% of the air in our atmosphere is made of Nitrogen
 Body does not use the nitrogen it inhales: Nitrogen in its gaseous form is

almost entirely unusable to life forms.

 For life forms to use Nitrogen, It must first be converted or ‘fixed’ into a more
usable form.
o The process of converting N2 into Ammonia (NH3) is
called Nitrogen Fixation
o There are specialized bacteria whose function it is
to fix nitrogen, converting it, so that it can be used
by plants.

 Other soil bacteria obtain energy by converting nitrates into nitrogen gas (N2)
which is released into the atmosphere in a process called DENITRIFICATION

 After nitrogen is fixed, it can be absorbed, and used by plants, and
subsequently by animals.

 The process of nitrogen being fixed, used by plants and animals, and later
returned to the atmosphere is referred to as the NITROGEN CYCLE

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