Chapter
#3
“Ecosystems and Energy”
(Pg. 46 – 55)
Readings this week and
previous weeks:
Chapter #1 – “Hooknose”
Chapter #2 – “The Five Houses of Salmon”
Chapter #3 – “New Values for the Land and
Water”
Chapter #4 – “The Industrial Economy
Enters the Northwest”
In-class Discussion Readers:
Chapter #1 - Me
Chapter #2 – David Dudley
Chapter #3 – Elizabeth Goodrich
Chapter #4 – James McLeod
Chapter #5 – Labecca Hampton and Jessica Vidal
Chapter #6 – Patrick Grennan and Scott Arnold
Chapter #7 – William Arnold
Chapter #8 – Crisy Overgard
Chapter #9 – Juan Rodriguez
Ecology
o
Ecology
•
•
•
o
Biotic- living environment
•
o
“eco” house & “logy” study of
The study of interactions among and between organisms
in their abiotic environment
Broadest field in biology
Includes all organisms
Abiotic- non living or physical environment
•
Includes living space, sunlight, soil, precipitation, etc.
Ecology
o
o
Biology is very
organized.
Ecologists are
interested in
the levels of
life above that
of organism.
Ecological Definitions
o
Species
•
o
Population
•
o
Al the populations of different species that live and interact in the
same area at the same time.
Ecosystem
•
o
A group of organisms of the same species that occupy that live in
the same area at the same time.
Community
•
o
A group of similar organisms whose members freely interbreed.
A community and its physical (abiotic) environment.
Landscape
•
Several interacting ecosystems.
Ecology
The biosphere contains earth’s communities, ecosystems
and landscapes, and includes:
o
•
•
•
Atmosphere- gaseous
envelope surrounding
earth
Hydrosphere- earth’s
supply of water
Lithosphere- soil and
rock of the earth’s crust
Energy
o
The ability or capacity to
do work
•
o
Chemical, radiant, thermal,
mechanical, nuclear,
electrical
Energy exists as either:
•
•
Stored energy (potential
energy)
Kinetic energy (energy of
motion)
Thermodynamics
o
o
Study of energy and its transformations
System- the object being studied
•
•
Closed System- Does not
exchange energy with
surroundings (rare in nature)
Open System- exchanges
energy with surroundings
Laws of Thermodynamics
o
First Law of Thermodynamics
•
Energy cannot be created or destroyed; it can change
from one form to another
•
•
o
Ex: organisms cannot create energy they need to survive- they
must capture it from another source
Focus is on quantity
Second Law of Thermodynamics
•
When energy is converted form one form to another,
some of it is degraded to heat
•
•
Heat is highly entropic (disorganized)
Focus is on quality
Photosynthesis
o
Biological process by which energy from the sun
(radiant energy) is transformed into chemical
energy of sugar molecules
6 CO2 + 12 H2O + radiant energy
C6H12O6 + 6 H2O + 6 O2
o
Energy captured by plants via photosynthesis is
transferred to the organisms that eat the plants
Cellular Respiration
o
The process where the chemical energy captured in
photosynthesis is released within cells of plants and
animals
C6H12O6 + 6 O2 + 6 H2O
6 CO2 + 12 H2O + energy
o
This energy is then used for biological work
•
Creating new cells, reproduction, movement, etc.
Energy Flow
o
Passage of energy in a
one-way direction
through an ecosystem
•
•
•
•
Producers
Primary consumers
Secondary consumers
Decomposers
Food Chains- The Linear Path of Energy Flow
o
Energy from food passes from one organisms to
another
•
Each “link” is called a trophic level
Food webs represent interlocking food chains that
connect all organisms in an ecosystem
In-class Discussion Readers:
Chapter #1 - Me
Chapter #2 – David Dudley
Chapter #3 – Elizabeth Goodrich
Chapter #4 – James McLeod
Chapter #5 – Labecca Hampton and Jessica Vidal
Chapter #6 – Patrick Grennan and Scott Arnold
Chapter #7 – William Arnold
Chapter #8 – Crissy Overgard
Chapter #9 – Juan Rodriguez
Readings last Week and this
Week:
Chapter #5 – “Free Wealth”
Facilitators: Labecca Hampton
and Jessica Vidal
Quizzes will be returned on Wednesday
Ecological Pyramids
o
Graphically represent the relative energy value of
each trophic level
•
o
Important feature is that large amount of energy are lost
between trophic levels to heat
Three main types:
•
•
•
Pyramid of Numbers
Pyramid of Biomass
Pyramid of Energy
Pyramid of Numbers
o
Illustrates the number of organisms at each trophic
level
•
•
o
Usually, organisms at the base of the pyramid are more
numerous
Fewer organisms occupy
each successive level
Do not indicate the biomass
of the organisms at each
level or the amount of
energy transferred between
levels
Pyramid of Biomass
o
Illustrates the total biomass at each successive trophic
level
•
•
o
Biomass: measure of the total amt of living material
Biomass indicates the
amount of fixed energy at a
given time
Illustrates a progressive
reduction in biomass
through trophic levels
Pyramid of Energy
o
Illustrates how much energy is present at each trophic
level and how much is transferred to the next level
•
o
Most energy dissipates between trophic levels
Explains why there are so
few trophic levels
•
Energy levels get too low
to support life
Ecosystem Productivity
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Gross Primary Productivity (GPP)
•
o
Net Primary Productivity (NPP)
•
•
o
Total amount of energy that plants capture and
assimilate in a given period of time
Plant growth per unit area per time
Represents the rate at which organic material is actually
incorporated into the plant tissue for growth
GPP – cellular respiration = NPP
•
Only NPP is available as food to organisms
Variation in NPP by
Ecosystem
Human Impact on NPP
o
Humans consume more of earth’s resources that
any other animal
•
•
o
o
Humans represent 0.5% of land-based biomass
Humans use 32% of land-based NPP!
This may contribute to loss of species (extinction)
Humans’ high consumption represents a threat to
planet’s ability to support both human and nonhuman inhabitants (structural and functional integrity)