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Chapter 3

Matter, Energy & Life

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Outline

• Elements of Life

• Organic Compounds and Cells

• Energy

Laws of Thermodynamics

Photosynthesis/Respiration

• Ecosystems

Food Chains

Ecological Pyramids

Material Cycles

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Elements of Life

• MATTER - everything that has mass and

takes up space

Solid - Liquid - Gas = 3 states of matter

• CONSERVATION OF MATTER: The idea

that matter cannot be created nor destroyed

but is simply transformed from one form to

another

• The atoms in your body may have been in a

dinosaur or a tree!

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Elements

• ELEMENTS - substances that cannot be

broken down into simpler forms by ordinary

chemical reactions

• All matter consists of elements.

• 118 elements, but just four (oxygen, carbon,

hydrogen and nitrogen) make up 96% of the

mass of living organisms.

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Elements of Life • All elements are composed of atoms.

• ATOMS - smallest particles exhibiting characteristics of the element

• Atoms are composed of:

PROTONS (positively charged +)

NEUTRONS (neutrally charged)

ELECTRONS (negatively charged -)

Protons &neutrons are in the nucleus

Electrons orbit the nucleus.

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Elements of Life ATOMIC NUMBER: Number of protons

ATOMIC MASS: Number of protons and neutrons in an atom. Average of all isotope masses

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Elements of Life

ISOTOPE - forms of an element differing in atomic mass due to the fact that isotopes have different numbers of neutrons

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Radioactive Isotopes

Unstable isotopes release energy and/or particles: Alpha, Beta or Gamma rays

Decay ends as a stable

form or another element

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Molecules & Compounds

• MOLECULE: two or more atoms joined together

• COMPOUND: a substance composed of 2 or more different kinds of atoms

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Ionic Chemical Bonds

CHEMICAL BOND - chemical energy holding atoms together to form molecules

IONIC BOND - Atoms with opposite charges (ions) form a bond. One atom loses one or more electrons, the other atom gains one or more electrons

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Ionic Chemical Bonds

IONS - atoms that contain more or fewer electrons

than protons and therefore have a positive or

negative charge

ANIONS (-) have a negative charge.

CATIONS (+) have a positive charge.

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Covalent Chemical Bonds

COVALENT - atoms share electrons

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WATER IS DIFFERENT!

COVALENT BONDS IN WATER

In water the oxygen attracts the electrons more strongly than the hydrogen atoms do, so the hydrogen atoms have a slight positive charge and the oxygen has a slight negative charge.

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WATER IS DIFFERENT! Water molecules are attracted

to each other due to the Polar Covalent bonds of other water molecules

“Universal Solvent” due to its polar nature, water is capable of dissolving most molecules

Cohesion – the attraction between water molecules

Surface Tension – the resistance of surface molecules to be broken

Adhesion - water molecules bonding to another surface

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WATER IS DIFFERENT! High Heat of Vaporization - requires a lot of energy

to turn liquid water into a vapor/gas

High Specific Heat – water must absorb a lot of heat energy for the temperature to rise & it holds onto this heat energy for a long period of time

Water EXPANDS when it freezes – this makes ice less dense than liquid water allowing it to float

Water has a pH of 7 – it is NEUTRAL – in solution the molecules break apart into (OH-) Hydroxyl Ions and (H+) Hydrogen Ions

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Oxidation and Reduction

• OXIDATION - When an atom gives up one or more electrons, it is “oxidized”.

• REDUCTION - When an atom gains one or more electrons, it is “reduced”.

• Oxidation and reduction are important parts of how organisms gain energy from food.

• Endothermic: breaking bonds absorbs energy

_________________________________________

• Exothermic: forming bonds releases energy

_________________________________________

• Activation Energy: the energy needed to initiate a chemical reaction (ie: friction to light a match)

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Acids, and Bases

• ACID – a substance that releases hydrogen ions

when put into water.

Acids are Hydrogen (H+) “donors”

ie: sulfuric, hydrochloric, acetic, carbonic

• BASE – a substance that releases hydroxide ions

(OH-) in water

Bases easily bond with hydrogen ions producing

water and a neutral pH

ie: sodium hydroxide, calcium hydroxide

ammonium hydroxide,

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pH Scale

pH scale:

is logarithmic;

each step is 10X

0 to 6.9 is acidic

7 is neutral

7.1 to 14 is basic

ie: a substance with a

pH of 4 is ________x

More acidic than a

substance with a pH of 6

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ENVIRONMENTAL BUFFERS

BUFFER:

a substance that accepts or releases

hydrogen ions

buffers help to neutralize a solution

ie: adding lime (calcium carbonate) to a lawn will

decrease effects of acid rain

ie: a lake affected by acid rain may be buffered

by surrounding soils or alkaline bedrock of

limestone or igneous type rocks.

(Granite & shale are acidic and would be

detrimental to a lake affected by acid rain.)

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Organic Compounds

• Organic Compounds - Material making up

biomolecules, which in turn make up living things.

All organic compounds contain carbon.

• Four major categories of organic compounds:

- _________________

- _________________

- _________________

- _________________

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LIPIDS - CHO

Lipids

Fatty acids, oils, steroids, waxes, some hormones

store energy

produce cell membrane

do not easily dissolve in water (non-polar)

Hydrocarbon family (petroleum, methane)

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CARBOHYDRATES - CHO

Carbohydrates

Monosaccharides: simple sugars (glucose,

sucrose, lactose)

Polysaccharides: starch & cellulose

Store energy

Used in cellular structure

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PROTEINS – CHON (S)

Proteins

- Composed of chains of amino acids

20 types of amino acids

- Folded into 3D shapes & perform countless

functions in cells and organisms

antibodies, enzymes, cell shape,

hormones, transport other substances,

muscle contractions, etc.

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NUCLEOTIDES / NUCLEIC ACIDS - CHONP

Nucleotides are monomers that combine to

create nucleic acids

- Made of a sugar, a phosphate group and

a nitrogen containing base

- Form long chains of RNA and DNA

- 4 types of DNA Nucleotides

adenine

guanine

cytosine

thymine (uracil in RNA)

- DNA extraction is very useful in taxonomy,

agriculture (GMO’s), medical genetics, etc.

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ORGANISM FUNCTIONING • Cells - minute parts of a living organism which

carry out processes of life

Surrounded by lipid & protein membrane controlling flow of materials in and out of the cell

Cells are composed of organelles that perform cell functions.

Prokaryotes – bacteria

Archea – single-celled extremophiles

Eukaryotes – protists, fungi, plants animals

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ORGANISM FUNCTIONING

• Enzymes - Molecular catalysts that regulate chemical reactions. Enzymes are usually proteins.

• Metabolism – the total of all enzymatic reactions performed by an organism

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ENERGY

ENERGY – the ability to do work

KINETIC - energy in moving objects

POTENTIAL - stored energy

CHEMICAL – potential energy stored in food or fossil fuels

NUCLEAR – nuclear atomic particles give way to radioactive decay

GRAVITATIONAL – due to height. Becomes kinetic energy when the object falls

MAGNETIC – forces between magnetic materials (poles & distance)

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ENERGY • MEASURING ENERGY

Units of heat – Calorie - amount of energy needed to heat 1 gram of H2O 1oC

Units of work – Joule - work done to accelerate 1kg at one meter per second per second (m/s/s)

1 calorie = 4.184 J

• ENERGY vs POWER

Energy is the ability to do work

Power is the rate at which work is done

Energy = power x time

Power = energy time

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HEAT ENERGY

• HEAT - Energy that can be transferred between objects of different temperature.

When a substance absorbs heat, the motion of its molecules increases and it may change state (e.g. a solid to a liquid to a gas).

When a substance releases heat, the motion of its molecules decreases and it may change state (e.g. a gas to a liquid to a solid).

Remember.........

Evaporation and condensation help distribute heat around the globe. (Convection Currents)

Heat storage in lakes & oceans moderates climate and helps maintain different biomes

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USEFUL ENERGY

• Forms of energy that can be used for work is

considered useful and HIGH-QUALITY.

• Diffuse forms of energy that can not be used

for work are considered LOW-QUALITY.

Which of the following have useful energy?

Atlantic Ocean a flame

a piece of coal a flowing stream

a warm brick a rock rolling downhill

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• HEAT - can be transferred between objects by convection, conduction and radiation.

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THERMODYNAMICS: The study of Energy

• FIRST LAW OF THERMODYNAMICS -

a.k.a. Law of Conservation of Energy Energy is neither created nor destroyed. The amount of energy in the universe is constant.

• SECOND LAW OF THERMODYNAMICS -

With each successive energy transfer, less energy is available to perform work.

- ENTROPY (disorder) increases as energy is used to do work.

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• ENTROPY is a thermodynamic quantity

representing the amount of energy in a

system that is no longer available for doing

mechanical work.

• As energy is used in doing work, some

energy is lost from the system.

Lost as Heat, Friction, Sound, etc. • Video: https://www.youtube.com/watch?v=sAMlGyaUz4M

EXAMPLES:

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Energy for Life

• Energy must be continually supplied by the sun to keep biological processes running. As energy flows through the various biological processes, it becomes dissipated, diffuse, unable to be used.

• Ultimately, most organisms depend on the sun for the energy needed to carry out life processes.

Exception: ____________________________

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Energy from the Sun

• Solar energy is essential for 2 reasons:

Warmth - Most organisms can exist only in a

relatively narrow temperature range.

If too cold - ____________________________

If too hot - _____________________________

Photosynthesis in plants

- Radiant energy is transformed into useful,

high-quality chemical energy in the bonds of

organic molecules. Almost all life on Earth

depends on photosynthesis.

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Energy From the Sun

• PHOTONS – Massless packets of electromagnetic

radiation that travel at the speed of light.

Long wave energy (radio waves) are low energy

Short wave energy (x-rays) are high energy

• Of all insolation reaching the earth’s surface:

10% is ultraviolet

45% is visible light

45% is infrared

Most energy is absorbed by the land &/or water,

or reflected back into space.

Only 1-2% of the sunlight falling on plants is

captured for photosynthesis.

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Electromagnetic Spectrum

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Photosynthesis

• Occurs in chloroplasts within plant cells

• 6H20 + 6CO2 + solar = C6H12O6 + 6O2

energy

• Water and carbon dioxide in the presence of

sunlight and chlorophyll (the green pigment

in chloroplasts) yield glucose and oxygen.

• Glucose serves as primary fuel for all

metabolic processes. Energy in its chemical

bonds can be used to make other

biomolecules (lipids,proteins) or it can drive

movement, transport, etc.

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CHEMOSYNTHESIS

• Ancient organisms called ARCHAEA get

their energy from inorganic compounds such

as H2 and S found in vents in the sea floor or

from hot springs.

• ARCHAEA represent one-third of all the

biomass on the planet.

• Those living in ocean sediments create

enormous quantities of methane.

Fortunately, bacteria which consume

methane also exist.

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Cellular Respiration

• Photosynthesis captures energy, while cellular respiration releases energy. They are opposite processes!!

• C6H12O6 + 6O2 = 6H2O + 6CO2 + energy

(AEROBIC respiration provides more energy than ANAEROBIC respiration)

This is how animals get all their energy. The reason that you need to breathe is to supply this pathway with oxygen.

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Energy

Exchange in

Ecosystems

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From Species to Ecosystems

• Species - all organisms of the same kind that

are genetically similar enough to breed in

nature and produce live, fertile offspring

• Population - all members of a species living

in a given area at the same time

• Biological Community - all of the

populations of organisms living & interacting

in a particular area a.k.a. BIOTIC FACTORS

• BIOMASS - the total mass of all living matter

in a specific area

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From Species to Ecosystems

• Ecosystem – a biological community and its

physical environment

The physical environment includes ABIOTIC

(non-living) FACTORS such as climate, water,

minerals, soil, energy, etc.

It is difficult to define the boundaries of an

ecosystem. Most ecosystems are open in that

they exchange materials and organisms with

other ecosystems.

• BIOSPHERE – all ecosystems on earth. From

deepest ocean trench to highest mountain peaks.

(20 km thick layer around earth)

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ECOSYSTEM PRODUCTIVITY

• PRODUCTIVITY - the amount of biomass produced in a given area in a given period of time.

• PRIMARY PRODUCTIVITY – synthesis of organic matter (biomass) by plants using solar energy during photosynthesis.

• SECONDARY PRODUCTIVITY - manufacture of biomass by organisms that eat plants.

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ECOSYSTEM PRODUCTIVITY

• GROSS PRIMARY PRODUCTIVITY (GPP) measure of the total amount of solar energy captured by producers during photosynthesis.

• NET PRIMARY PRODUCTIVITY (NPP) - measure of the total energy captured minus the energy respired by producers.

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GPP VS NPP

NPP = GPP – Respiration

MEASURING GPP

Total CO2 taken up during photosynthesis =

CO2 taken up in light + CO2 produced in dark

This figure is expressed as

Kg C / m2 / day (year)

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CALCULATING NPP

A forest in N. America has a GPP of

2.5 kg C / m2 / year

This same forest loses 1.5 kg C / m2 / year

due to respiration.

Calculate the NPP in terms of % of GPP

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NPP for Ecosystems

• NPP is highest where temp is high, large

amounts of water and sunlight are present

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Identify 3 food chains in the picture below.

Each chain must have at least 3 organisms

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Food Chains and Food Webs

Food Chain – sequence of consumption from producer to consumers

Food Web – multiple food chains, shows complex relationships.

Trophic level - An organism’s feeding status in a food web.

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TROPHIC LEVELS - Producers

PRODUCERS – AUTOTROPHS

All plants,

Some protists – ALGAE

Chemosynthetic Archaea

Some bacteria

These organisms produce glucose through

photosynthesis or chemosynthesis and are

the base of the food chains.

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TROPHIC LEVELS - Consumers

CONSUMERS – HETEROTROPHS

All animals

Some protists – PROTOZOA

Herbivores eat only plants

____________________________

Carnivores eat only animals - wolves

____________________________

Omnivores eat both plants & animals

Bears, fox, raccoons

____________________________

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TROPHIC LEVELS – Consumers

Some animals feed on dead organic matter

SCAVENGERS eat carcasses

____________________________

DETRITIVORES eat debris

(waste/decaying matter) breaking it down

into smaller pieces called DETRITUS

____________________________

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TROPHIC LEVELS - Decomposers

DECOMPOSERS – SAPROTROPHS

- most BACTERIA

- All FUNGI – (mushrooms, mold)

Decomposers break down detritus into

elements and smaller molecules to be

recycled back into ecosystems through

matter cycles.

THIS IS AN EXTREMELY IMPORTANT ROLE

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PROCESS OF DECOMPOSITION

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Ecological Pyramids

• Due to the Second Law of Thermodynamics, energy is lost at each level of the pyramid.

Energy is lost as heat during metabolism.

Some energy is lost due to inefficient predation.

10% Rule (Energy / Biomass)

100 kg of clover yields

10 kg of rabbit which yields

1 kg of fox which yields

0.01 kg of eagle

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Energy Pyramid

When organisms at various trophic levels are arranged diagrammatically, they form a pyramid with many more producers than consumers.

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Remember - 90% of energy is lost at each step

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INVERTED FOOD PYRAMIDS

INVERTED FOOD PYRAMIDS NEVER

REPRESENT ENERGY!!!

Inverted pyramids exist under a few conditions:

In this example, a single tree

can support hundreds or

thousands of insects which in

turn can support a few

carnivorous birds such as

woodpeckers.

Draw a fourth level

representing a hawk which

may prey on the woodpecker.

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INVERTED FOOD PYRAMIDS

Inverted pyramids exist under a few conditions:

In this example, a field of grass can support a few rabbits

which in turn support thousands of parasites – both internal

and external.

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INVERTED FOOD PYRAMIDS Inverted pyramids exist under a few conditions:

Aquatic ecosystems are often inverted at the primary

consumer level. Phytoplankton reproduce quickly and have

short lives so there are never as many as the next level.

In contrast, grasses have longer lives and are rarely

consumed in their entirety. Thus, are a broader base for

terrestrial food pyramids.

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BIOGEOCHEMICAL CYCLES Matter is conserved as it cycles over and over

through ecosystems.

1. HYDROLOGIC CYCLE

2. CARBON CYCLE

3. NITROGEN CYCLE

4. PHOSPHORUS CYCLE

5. SULFUR CYCLE

SOURCE – releases more of a compound than it absorbs

SINK – stores more of a compound than it releases

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Hydrologic Cycle

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HYDROLOGIC CYCLE

• Path of water through the environment

1. Solar energy evaporates water from surface supplies and land.

2. Water is released by plants via TRANSPIRATION

3. Winds distributes water vapor around the globe.

4. Water vapor condenses over land surfaces, producing precipitation.

5. Water runs off, percolates into sediment or is taken up by plants

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Carbon Cycle

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Carbon Cycle

• Begins with intake of CO2 during photosynthesis. Carbon atoms are incorporated into sugar which is eventually released by cellular respiration either in the plant or in organisms that consumed it.

• Sometimes the carbon is not recycled for a long time. Coal and oil are the remains of organisms that lived millions of years ago. The carbon in these is released when we burn them. Some carbon is also locked in calcium carbonate (shells, limestone).

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Carbon Cycle

• The parts of the cycle that remove and store carbon

dioxide from the atmosphere (vegetation) are called

carbon sinks.

• The parts of the cycle that release carbon dioxide

are called carbon sources.

• Burning of fuels generates huge quantities of

carbon dioxide that cannot be taken up fast enough

by the carbon sinks. This excess carbon dioxide

contributes to global warming.

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Nitrogen Cycle

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Nitrogen Cycle

• Nitrogen is needed to make proteins and nucleic acids such as DNA.

• Plants take up inorganic nitrogen from the environment and build protein molecules which are later eaten by consumers.

Nitrogen-fixing bacteria change nitrogen to a more useful form by combining it with hydrogen to make ammonia. Other bacteria convert ammonia to nitrites and then nitrates, which can be taken up by plants to make proteins.

- Members of the bean family (legumes) have nitrogen-fixing bacteria living in their root tissue.

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Nitrogen Cycle

Nitrogen re-enters the environment:

- By death of organisms

- Animal excrement and urinary wastes

Nitrogen re-enters atmosphere when denitrifying bacteria break down nitrates into N2 and nitrous oxide (N2O) gases.

- Humans have profoundly altered the nitrogen cycle via use of synthetic fertilizers, nitrogen-fixing crops, and fossil fuels.

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Phosphorus Cycle

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Phosphorus Cycle

• Phosphorus is needed to make DNA, & ATP (the

energy currency of the cell) and other important

biomolecules.

• Phosphorus compounds are leached from rocks

and minerals and usually transported in aqueous

form.

Taken in and incorporated by producers

- Passed on to consumers

Returned to environment by decomposition

• Cycle takes a long time as deep ocean sediments

are significant sinks

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Sulfur Cycle

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Sulfur Cycle

• Most sulfur is tied up in underground rocks and

minerals. Inorganic sulfur is released into air by

weathering and volcanic eruptions.

Cycle is complicated by large number of

oxidation states the element can assume.

Human activities release large amounts of sulfur,

primarily by burning fossil fuels.

- Important determinant in acid rain