Atoms to Ecosystems
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Environmental Science - systemic study of
the social/cultural, physical and biological
factors involved in the status of the
environment
Ecosystems form through the
complex interactions of matter
 Atom
 Molecules
 Cells
 Organism
 Populations
 Communities
 Ecosystems
 Biomes
From Atoms to Cells

Atoms, Molecules, and Compounds 3.3
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Atoms: The smallest unit of matter that has the
characteristics of an element
Molecules and Compounds form when 2 or more
atoms join together by a chemical bond
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Organic Compounds
–
Organic Compounds: Complex molecules
organized around skeletons of carbon atoms
arranged in rings or chains
Cells
The Fundamental Units of Life
Cells: Minute biological
compartments within which the the
processes of life are carried out
–
Enzymes: Molecules, usually proteins
or nucleic acids, that act as catalysts in
biochemical reactions
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Metabolism: All the energy and matter
exchanges that occur within a living cell
or organism
Matter:
Something that occupies
space and has mass
Energy: The ability to do work
–
Kinetic Energy: Energy contained in
moving objects such as a rock rolling
down a hill
–
Potential Energy: Stored energy that
is latent but available for use
–

Temperature: A measure of the speed of
motion of a typical atom or molecule in a
substance
Conservation of Matter
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Conservation of Matter: In any chemical
reaction, matter changes form; it is neither
created nor destroyed

Thermodynamics and Energy Transfers
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The First Law of Thermodynamics: States
that energy is conserved; that is, it is neither
created nor destroyed
The Second Law of Thermodynmics: all
systems tend toward a state of increasing
disorder
Energy for Life

Solar Energy: Warmth and Light 3.6
–

Photosynthesis: The biochemical process by
which green plants and some bacteria capture
light energy and use it to produce chemical
bonds
How Does Photosynthesis Capture
Energy? 3.7 & 3.8
PHOTOSYNTHESIS
Sunlight
changes
Carbon dioxide and Water
into
Sugar and Oxygen
Sugar is chemical energy
photosynthesis
Cellular Respiration:
Sugar, protein, fats and nucleic acids
(foods) are processed by the cell to
release energy for cellular work.
Sugar + oxygen makes carbon
dioxide, water and Energy
Cellular Respiration:
From Species to Ecosystems

Population, Communities, and
Ecosystems
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Species: A population of morphologically
similar organisms that can reproduce sexually
among themselves but that cannot produce
fertile offspring when mated with other
organisms

Populations, Communities, and
Ecosystems
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–
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Population: A group of individuals of the same
species occupying a given area
Biological Community: The populations of
plants, animals, and microorganisms living and
interacting in a certain area at a given time
Ecosystem: A specific biological community
and its physical environment interacting in an
exchange of matter and energy

Food Chains, Food Webs, and Trophic
Levels 3.9, 3.10, 3.11
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Productivity: The amount of biological matter
or biomass produced in a given area during a
given unit of time
Biomass: The total mass or weight of all the
living organisms in a given population or area
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Food Chain: A Linked feeding series; in an
ecosystem, the sequence of organisms through
which energy and materials are transferred, in
the form of food, from one trophic level to
another
Food Web: A complex, interlocking series of
individual food chains in an ecosystem
Trophic Level: Step in the movement of
energy through an ecosystem; an organsism’s
feeding status in an ecosystem
Ecosystem
Biotic Factors
All Living Organisms
Monera
Protista
Fungi
Plants
Animals
Abiotic Factors
Physical Variables in an
Organisms Environment
Temperature
Water
Sunlight
Wind
Soil
Disturbance
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Producer: An organism that synthesizes food
molecules from inorganic compounds by using
an external energy source
Consumer: A organism that obtains energy and
nutrients by feeding on other organisms or their
remains
CONSUMERS THAT EAT
Herbivore: An organism that eats
only plants
Carnivore: Organisms that mainly
prey upon animals
Omnivore: A organism that eats both
plants and animals
CONSUMERS THAT DECOMPOSE
Scavenger: An organism that feeds on
the dead bodies of other organisms
Detritivore: Organisms that consume
organic litter, debris, and dung
Decomposers: Fungi and bacteria that
break complex organic material into
smaller molecules
Nutrient Cycles and
Life Processes
Carbon Cycle: Carbon is the basis of all macromolecules
that form life on earth
1.
Carbohydrates
2.
Proteins
3.
Lipids (fats)
4.
Nucleic Acids (DNA & RNA)
Cycles Photosynthesis and Cell Respiration

The Nitrogen Cycle 3.16
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Nitrogen Cycle: The circulation and
reutilization of nitrogen in both inorganic and
organic phases
Nitrogen is in Protein, DNA and RNA
Root Nodule
are formed by
nitrogen
fixing bacteria
The Phosphorus Cycle 3.18
Phosphorus Cycle: The movement of
phosphorus atoms from rocks through the
biosphere and hydrosphere and back to rocks
Phosphorus is found in DNA, RNA and in all
membranes of cells.
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The Sulfur Cycle 3.19
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Sulfur Cycle: The cycling of inorganic sulfur
as it is released into the air and water by
weathering, emissions from seafloor vents, and
by volcanic eruptions
Properties of Water
>70% of the weight of living organisms is
water
 Universal solvent that is charged
 Water separates into H and OH ions cause
acidic, basic or neutral solutions
 The molecules are cohesive and adhesive
 It has a high specific heat
 It has a high heat of vaporization
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Properties of Water
The molecules are cohesive and adhesive
 It has a high specific heat
 It has a high heat of vaporization
 Water expands when it freezesfloats
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We are shaped by our environment