Obj. 3
ECOSYSTEMS: HOW THEY WORK
Matter, Energy and Life
Fig. 3.1 From a biological point of view, the three most important gases of the lower atmosphere are
____________________, ____________________, and _____________ ___________________.
Fig. 3.2 Water consists of______________________________, each of which is formed by two hydrogen
atoms bonded to an oxygen atom (H2O). In water vapor, the molecules are separate and independent.
Fig. 3.5 The organic molecules making up living organisms are larger and more complex than the
inorganic molecules found in the environment. Glucose and cysteine show this relative complexity.
Fig. 3.3 The atoms of most elements gain or lose one or more electrons, becoming
___________________(-) or ___________________ (+) ions. The ____________ are held together by
an attraction between positive and negative ____________________.
Fig. 3.6 Biological systems include____________________ of complexity beginning with atoms and
molecules and broadening up to the biosphere.
Fig. 3.7 ____________ energy is energy in one of its active forms. ___________________energy refers
to systems or materials that have the potential to release kinetic energy.
Fig. 3.8 Any form of energy can be converted to any other form, except heat energy. Heat
is a form of energy that flows from one system or object to another because the two are at different
temperatures. Therefore it can only be transferred to something cooler.
III. Energy
A. First Law of Thermodynamics: "_________________ is neither created nor
destroyed; it only changes form." It can be related to: "You can't get something for
nothing" or "There is no such thing as a free lunch".
B. Second Law of Thermodynamics: "_____________________ will go
spontaneously in one direction only toward increasing entropy." It can be described
as:" It takes _________________ to get _______________" or "In any energy
conversion, you will end up with ________________ usable energy than you started
with" or "If you think things are confused now, just wait" or "Everything moves in the
direction of increasing ________________________".
Fig. 3.9 When glucose is burned, _______________ is released, and the atoms become more
disordered, showing increasing entropy. The fact that wood will burn but not form spontaneously is an
example of the______________________ law of thermodynamics.
Fig. 3.11 Breaking down some of the glucose to provide additional __________________energy,
producers combine the remaining glucose with certain nutrients from the soil to form other complex
_____________________molecules that the _____________________then use for growth.
Fig. 3.13 Only a small portion of ingested food is used for growth and repair. A larger amount is used in
_______________ ___________________ to provide _____________________.
Fig. 3.15 This figure shows _________ ____________through Trophic Levels in a Grazing Food Web.
Each ___________ ______________is represented as biomass boxes and the pathways taken by the
energy flow are indicated with arrows.
IV. Principles of Ecosystem Function and Energy Flow in Ecosystems
A. Energy Source
1. The ultimate source of energy on our planet: _______ ___________
2. The first basic principle of ecosystem sustainability: "For sustainability,
__________________ use sunlight as their _____________of ___________.'
Our planet is sustainable as long as the _________exists.
________________do not use energy at a faster rate than that available from the sun.
(The same cannot be said for humans because of our rate of fossil fuel consumption.)
B. Nutrient Cycles:
Energy___________ but nutrients__________. The molecules in an organism will
eventually be _______________in another organism.
1._________________ ________________: Changing the location of this
element is the primary issue in global warming. We are moving carbon from where it
has been _______________(fossil fuels) to the atmosphere, where it acts
to____________ the amount of heat reradiated to space.
·
The rate of _________________(flows) between pools can be slow or
fast depending upon the nature of the pool.
Fig. 3.16 Boxes in the figure refer to pools of carbon, and arrows refer to the movement, or fluxes, of
carbon from one pool to another.
2.________________ _____________: Changing the location of this element is
one of the primary reasons for the __________________nutrient load in aquatic
ecosystems. We move phosphorus from where it has been concentrated, e.g., in
guano, and deposit it on soil (or in consumer products), where it is released
to______________.
·
The rate of _________________(flows) between pools can be slow or
fast depending
upon the ___________________of the pool.
Fig. 3.17 This figure shows the movement of ____________________through an ecosystem.
3. Nitrogen Cycle: Changing the _________________of this element is the other
reason for the increased nutrient load in aquatic ecosystems. (Nitrogen and
phosphorus are___________________ factors in aquatic ecosystems.)
·
The rate of movement (flows) between pools can be slow or fast
depending upon the nature of the pool.
·
The flow of nutrients into Chesapeake Bay (primarily____________)
has been cited as the primary reason for the outbreak of Physteria.
Fig 3.18 This figure shows the movement of nitrogen through an ecosystem.
4. The second basic principle of ecosystem sustainability:
" For sustainability, ecosystems dispose of wastes and replenish nutrients by
___________________all elements."
Fig. 3.20 Arranging organisms by feeding relationships and depicting the energy and nutrient inputs and
outputs of each relationship show a continuous recycling of nutrients in the ecosystem, a continuous flow
of energy through it, and a decrease in biomass.
IV. Implications for Humans
1. Ecosystems are an excellent role model for humans.
2. Some examples of________________________ human actions: fossil fuel use,
not returning the nutrients remaining in human sewage to soil, high meat consumption
levels of the industrialized countries, energy use in homes, consumer goods.
Fig. 3.21 To get ______pound of______ requires an expenditure of 16 pounds of feed. Said another way,
the grain consumed to support one person eating meat could support_____persons eating the ________
directly.
Fig. 3.22 This figure shows one way nutrient flow in a human society.