Food (chemical energy) is needed
for your cells to produce ATP
(cellular energy).
- Also supplies raw materials for
your body to build and repair.
When food is burned, most energy is released as
heat, which is measured in “calories”.
Energy in food molecules is released during
cellular respiration and used to produce ATP to
power cellular activities.
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Energy can be extracted from almost any type
of food
So why does it matter what foods you eat?
Not all materials needed for life processes can be made by the
body- we must eat ALL of the elements and molecules that the
body needs!
Examples of molecules made from raw food materials: enzymes,
lipids in cell membranes, DNA
A healthy diet provides all of the necessary raw
materials your body needs.
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Nutrients- molecules (matter) ingested from
the environment that are needed for metabolic
processes
Nutrients your body needs include: water,
carbohydrates, fats, proteins, vitamins, and
minerals.

Carbs are the main source of energy for the body

Simple Sugars (mono and disaccharides)


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Complex Sugars (polysaccharides)


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Fruits, honey, sugar cane
Used first for energy
Grains, potatoes, vegetables
Broken down into simple sugars to the be used for energy
In animals, excess blood sugar is
converted into glycogen which is stored in
the liver and skeletal muscle.

Additional excess sugar can also be converted to and stored as
body fat

A balanced diet provides nutrients in
adequate amounts and enough energy for a
person to maintain a healthful weight.
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If you undergo prolonged starvation, what
order will you use the following organic
compounds to obtain energy?
Choices: glucose, ATP, proteins, fats,
complex carbohydrates
Complex
carbs
ATP
Glucose
___________→
___________→
___________
Proteins
Fats
→_____________→
_______________
Why are proteins broken down for energy last?

They must first be turned into sugar. They are also
necessary for structure and processes so are saved as
long as possible.
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CHON
Make up:
Water
 Carbs
 Lipids
 Nucleic acids
 proteins

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Energy flows in a one way direction starting
from the sun (it is not recycled)
Matter is recycled through the biosphere


This is different than the one-way flow of
energy through an ecosystem
Biogeochemical Cycles- process in which
elements, chemical compounds (water and
nutrients), and other forms of matter are
passed from one organism to another and from
one part of the biosphere to another.
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respiration, photosynthesis, decomposition,
Biological- Cellular
nitrogen fixation, etc.
Geological- Erosion, rock formation, heat and pressure from the
earth
Chemical- formation of
clouds/precipitation
Physical- flow of running water
Logging, deforestation, burning fossil fuels,
Human Activity- wastes, fertilizers


Energy powers the cycles of matter
Matter is transformed, never created or
destroyed
• Water moves between oceans,
atmosphere, and land
• Can be inside or outside of organisms

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
Evaporation
Transpiration
Combustion
Respiration

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Condensation
Precipitation
Runoff
Groundwater
Also use evaporation

The cycling of carbon, nitrogen, and
phosphorus through organisms and the
environment are especially important

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Carbon is a major
component of all
organic compounds.
found in some inorganic
compounds
Example: calcium
carbonate (CaCO3) –
molecule that is part of
animal skeletons
Example: carbon
dioxide (CO2) - major
part of the atmosphere
and necessary for
photosynthesis.

Oxygen often cycles with carbon
through the biosphere, particularly due
to photosynthesis and cellular
respiration.

Fossil Fuels: Energy rich fuels (coal, oil, and
natural gas) created from carbon-containing
compounds of ancient, dead forests, marine
organisms, or other animals have been buried
and transformed by pressure and heat.

Major reservoirs (locations of large amounts) of
carbon in the biosphere include the:
Atmosphere
 Oceans
 Rocks
 Fossil Fuels
 Forests


Use your knowledge and the carbon cycle
diagram in the notes packet to complete the
questions on pg. 7 of the notes.

Nitrogen is required to make amino acids and
nucleic acids
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Different forms of nitrogen occur naturally in
the biosphere.
Nitrogen gas (N2)makes up 78% of earth’s
atmosphere.
Ammonia (NH3), nitrate ions (NO3-), nitrite
ions (NO2-) are found in soil, in the wastes
produced by many organisms, and in dead and
decaying organic matter.
Dissolved nitrogen exists in several forms in
the ocean and other large water bodies
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Only a handful of organisms – certain types of
bacteria – can use this form directly.
They “change” (=fix) the nitrogen into usable
forms
The usable forms can then be used by other
organisms
Thus, nitrogen-fixing bacteria are an essential
part of the nitrogen cycle.
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Nitrogen Fixation: The conversion of Nitrogen
Gas (not usable) into Ammonia, Nitrates, and
Nitrites (usable) by bacteria.
Some of these bacteria live in the soil whereas
others live on the roots of certain plants called
legumes (ex. peanuts, peas, soybeans).
Bacteria are the driving force of the nitrogen cycle!
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Once these forms of nitrogen are available,
primary producers can use them to make
proteins and nucleic acids.
Consumers eat the producers and reuse
nitrogen to make their own nitrogencontaining compounds (and so on through the
food web).

Eutrophication: excess
growth of algae due to
increased levels of fertilizers
in the water.


Creates an algal bloom
Algae takes oxygen from other
organisms and may release
toxins

Competition- when organisms attempt to use
the same limited ecological resource in the
same place at the same time.
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Predation: an interaction in which one animal
(the predator) captures and feeds on another
animal (the prey)
Predators can affect the size of prey
populations in a community and determine the
places prey can live and feed.
Give an example in our ecosystem
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Herbivory: an interaction in which one animal (the
herbivore) feeds on producers (such as plants)
Herbivores can affect both the size and
distribution of plant populations in a community
and determine the places that certain plants can
survive and grow.
Give an example in our ecosystem
What is shown in this graph?
Use the graph to answer the two questions
below it in the notes.

Keystone Species: a single species that is not
usually abundant in a community yet exerts
strong control on the structure of a community.

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A species whose presence is important for the
structure of a community
Example:
Kelp
Sea Urchin
Sea Otter
Due to
hunting
Provide shelter and
food for other animals
What will happen to this community?
Sea otters were a keystone species!
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Any relationship in which two species live
closely together is called symbiosis
Three main classes of symbiosis:
Mutualism
 Parasitism
 Commensalism

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A relationship in which
both species benefit
Example: clown fish live in
sea anemones.
 Clown fish are protected
from predators by hiding
inside the stinging
anemone
 The anemone is protected
from being eaten by the
clown fish who wants to
defend its home
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When one organism lives in or on another
organism and harms it by obtaining all or part
of its nutritional needs from the host organism.
Example: Fleas feed on blood and skin of their
hosts; cause discomfort and could transmit
disease

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One organism benefits and the other is neither
helped nor harmed
Example: barnacles (small ocean animals) live on
whales. They do not harm the whale but the whale’s
swimming allows the barnacles to get constant food
particles from the water.