unit 2: systems and cycles in nature

Unit 2: Systems and Cycles in Nature

Description:

Nature is full of complex systems that maintain balance over long periods of time, and in order to

understand them, it is necessary to study entire systems instead of isolated pieces of the puzzle. This unit

examines how the interactions of earth’s atmosphere, hydrosphere, lithosphere and biosphere create

complex cycles that are critical to sustaining life on the planet. We will focus on ecosystems, studying the

relationships that develop between organisms and their environment, and the value of those ecosystems

to humans.

Packet Contents:

Assignment: Due:

1. Chapter 2 vocab 9/15

2. Reading Questions 2A, Video Questions 2A 9/18

3. Reading Questions 2B, Video Questions 2B 9/22

4. Chapter 3 vocab 9/23or 24

5. Reading Questions 3A, Video Questions 3A 9/26

6. Reading Questions 3B, Video Questions 3B 9/29

7. Article #1 “Early Warning Signs” + Analysis Questions Week 1

Date Due Read Tonight RQ/VQ Article

M 9/15 Chapter 2 vocab due p.27-28 2A

#1 “Early Warning Signs” T 9/16 p.29-36

W 9/17 p.36-41

Th 9/18 *DUE: RQ/VQ 2A p.42-43 2B

F 9/19 p.43-46

S/S ”

M 9/22 *DUE: RQ/VQ 2B + Article Questions 3A

T 9/23 DUE: chapter 3 vocab p.57-60

W 9/24 Due: chapter 3 vocab p.60-65

Th 9/25 FRQ In Class Prompt

F 9/26 *DUE: RQ/VQ 3A * Quiz* p.65-76 3B

S/S

M 9/29 *DUE: RQ/VQ 3B Study! Study!

T 9/30 Study! Study!

W 10/1 Study! Study!

Th 10/2 Test Review Study! Study!

F 10/3 *Unit 2 Test (30 MCQ, 1 FRQ) Quizstars due by 8am

Chapter 2 Vocabulary List

Isotopes Capillary Action Power

Radioactive Decay System Analysis First Law of Thermodynamics

Half-Life Steady State Second Law of thermodynamics

Closed System Feedback Energy Efficiency

Inputs Open System Energy Quality

Outputs Negative Feedback Loops Entropy

Positive Feedback Loops Adaptive Management Plan

Reading Questions 2A

Opening Story: A Lake of Salt Water, Dust Storms, and Endangered Species

Earth is a single interconnected system.

All environmental systems consist of matter.

1. Why did Mono Lake develop large mineral structures?

2. What negative environmental consequences occurred as a result of Los Angeles building an

aqueduct to transport water from the lake to the city?

3. The Earth is a single interconnected system, but it can be subdivided into many smaller systems.

How does the nature of the problem to be studied determine the scale of the system chosen?

4. What is the difference between an atom, a molecule, and a compound?

5. How do different isotopes of the same element differ, and what is their significance?

6. How is the half-life of a radioactive element determined, and why is it important?

7. When scientists look for other planets that may have life, they focus on planets that contain water. How do the water’s unique properties make it key for supporting biological processes?

8. Why do coastal areas near lakes and oceans tend to see smaller swings in temperature from hot

to cold?

9. Suppose solution A has a pH of 3, solution B has a pH of 7 and solution C has a pH or 8. If

solution B has 100,000 H+ ions, how many H+ ions do each of solution A and C have?

10. As a tree grows, it’s mass increases. Why is this not a violation of the law of conservation of

matter?

11. Complete the following chart regarding the major types of macromolecules (organic matter):

Defining Characteristics Role in Cell/Organism Examples

Carbohydrates

Proteins

Nucleic Acids

Lipids

APES Video Questions 2A

Watch “Crash Course Chemistry #1: The Nucleus” (http://www.youtube.com/watch?v=FSyAehMdpyI)

Read the Focus Questions in advance to help you catch key information. Take notes while watching,

then summarize and answer the questions when you finish.

Take Notes as you watch:

Summarize Main Ideas

Focus Questions:

1. What are atoms composed of? Describe the properties of each component.

2. What are isotopes? Why are they important?

3. What role does charge play in atomic interactions?

Respond with your own thoughts, questions, connections, and conclusions:

Reading Questions 2B

Energy is a fundamental component of environmental systems.

Energy conversion underlies all ecological processes.

Systems analysis shows how matter and energy flow in the environment.

Natural systems change across space and over time.

Working Toward Sustainability: Managing Environmental Systems in the Florida Everglades

1. How does the Sun transfer energy from millions of miles away to Earth?

2. What is the difference between power and energy?

3. Why do you think we use the term power plants instead of energy plants?

4. What is the difference between potential energy and kinetic energy?

5. Certain chemical reactions give off heat when they occur. Describe what is happening in terms

of potential energy and kinetic energy in such reactions.

6. How is an object’s temperature related to the energy of its molecules?

7. The first law of thermodynamics states that energy can be neither created nor destroyed; do heat-emitting (exothermic) reactions violate this law? Explain.

8. According to the second law of thermodynamics, some energy is always lost as heat during any

energy conversion. Use this concept to explain why lights, engines, computers, muscles, etc. get

hot.

9. How can the efficiency of an energy transformation be calculated?

10. Use the second law of thermodynamics to explain why a barrel of oil can be used only once as a fuel. In other words: why can’t we recycle this high quality energy?

11. The second law of thermodynamics tells us that all systems slowly degrade towards

randomness. However, life on Earth has been incredibly successful at preserving itself and

growing increasingly complex over time. How has life been so successful doing this?

12. Earth is considered an open system for energy and a closed system for matter. Explain what this means.

13. What characterizes a steady state in a system? Are steady states generally a good or bad thing in environmental systems?

14. Explain the difference between a positive feedback loop and a negative feedback loop.

15. Are positive feedbacks necessarily good things? Are negative feedbacks necessarily bad things? Explain.

16. What can inputs, outputs and feedback loops tell us about the health of environmental systems?

APES Video Questions 2B

Watch “Crash Course Chemistry #17: Energy & Chemistry” (www.youtube.com/watch?v=GqtUWyDR1fg)





Focus Questions:

1. How can molecules contain energy in their bonds, mass and motion?

2. Heat and work are both transfers of energy – what distinguishes them?

3. How do exothermic and endothermic reactions perform energy transformations?


Chapter 3 Vocabulary List

Resilience Gross Primary Productivity (GPP) Limiting Nutrient

Resistance Net Primary Productivity (NPP) Nitrogen Fixation

Restoration Ecology Biomass Leaching

Intermediate Disturbance Hypothesis

Standing Crop Disturbance

Evapotranspiration Ecological Efficiency Watershed

Provisions Trophic Pyramid Instrumental Value

Intrinsic Value

Reading Questions 3A

Reversing the Deforestation of Haiti

Ecosystem ecology examines interactions between the living and the nonliving world.

Energy flows through ecosystems.

1. What happened to the rainforest in Haiti, and why? What effects did it have?

2. What did the US Agency for International Development do to try and correct the problem?

3. Why are both biotic AND abiotic components important to an ecosystem?

4. Why is it difficult to determine what the boundaries to an ecosystem are?

5. Can ecosystems be fully isolated from their surroundings? How does this influence ecosystem

studies?

6. How does most energy enter ecosystems? What types of energy conversion occur within

ecosystems?

7. How are trophic levels related to flow of energy through an ecosystem? What form is this

energy in?

8. What does the productivity of an ecosystem measure?

9. What is the difference between Gross Primary Productivity and Net Primary Productivity? Which

one do you think has more of an influence on an ecosystem, and why?

10. Approximately what percentage of incoming solar energy do plants capture during

photosynthesis? What happens to the rest of it?

11. Which terrestrial and aquatic ecosystems have the highest NPP? Why do you think this is?

12. What is the difference between the standing crop of biomass and productivity in an ecosystem?

13. Why is only a small fraction of energy at each trophic level transferred up to the next trophic

level? Where does the rest of the energy go?

14. As a general rule, the lower the NPP of an ecosystem, the larger the ranges of its top predators

must be. For example, sharks in the open ocean must cover huge distances. Why is this true?

APES Video Questions 3A

Watch “Life in Biosphere 2” (www.ted.com/talks/jane_poynter_life_in_biosphere_2.html)

(Or http://www.youtube.com/watch?v=a7B39MLVeIc)





Focus Questions:

1. How was Biosphere 2 set up, and what was it intended to study?

2. What were the major problems that developed in Biosphere 2?

3. What can we learn from the “industrial ecosystem” created in Eritrean shrimp farms &

mangrove forests? Could this model be adapted to other situations?


Reading Questions 3B

Matter cycles through the biosphere.

Ecosystems respond to disturbance.

Working Toward Sustainability: Can We Make Golf Greens Greener?

1. What is the difference between a pool (or stock) and a flow in biogeochemical cycles?

2. Hydrologic Cycle

Name of Step What process makes this

happen?

Why is this step important?

Evaporation Solar heating of oceans, lakes,

soils

Water enters atmosphere to be redistributed

3. Carbon Cycle

Name of Step w/ description of change

What organism/process does it? Why is this step important?

Photosynthesis (CO2C6H12O6) Autotrophs (plants) (producers) Converts abiotic CO2 to biomass (base of food chain)

4. Nitrogen Cycle

Name of Step w/ chemical change What organism/process does it? Why is this step important?

Nitrogen Fixation (N2NH3 or NO3) N-fixing bacteria (ie in legume roots) OR fires/lightning OR fertilizer manufacturing

Puts N in to the base of the food chain; fertilizer manufacture

5. Phosphorus Cycle

Name of Step w/ description of change

What process/organism does it? Why is this step important?

Weathering of rock Phosphate PO4 Weathering (by rain, wind, ice, organisms)

Releases P from rocks in to reactive form usable by organisms

6. How does the water cycle help facilitate the other cycles?

7. What human activities cause an impact on the hydrologic cycle? What are these impacts?

8. Explain the difference between the “fast” and “slow” parts of the carbon cycle.

Fast: Slow:

9. Which natural (nonanthropogenic) processes normally return buried carbon to the atmosphere

to balance out the carbon that is buried through sedimentation?

10. Which 2 macronutrients most frequently serve as the limiting nutrient for plant growth in an

ecosystem? Is it different for terrestrial vs. aquatic ecosystems?

11. What are the results of a sudden influx of excess nitrogen or phosphorus in to an ecosystem?

12. How do heterotrophs (consumers) obtain their supplies of macronutrients?

13. Although the most obvious forms of life on our plant are large plants and animals, the vast

majority of life is microbial. Paleontologist Andrew Knoll writes that “Prokaryotic metabolisms

form the fundamental ecological circuitry of life. Bacteria, not mammals, underpin the efficient

and long-term functioning of the biosphere".1 Defend or challenge the truth of this statement,

based on what you know about ecosystems and biogeochemical cycles.

14. When investigating environmental systems, why do scientists often select watersheds as an area

in which to study ecosystems and nutrient/energy cycling?

15. What characteristics do you think give ecosystems high resistance and high resiliency against

change?

16. What is restoration ecology?

17. Suppose ecosystem A experiences very few disruptions, ecosystem B experiences an

intermediate level of disturbances, and ecosystem C experiences very frequent disruptions, but

all 3 have roughly equivalent NPP and stored biomass. Which ecosystem would you expect to

have the highest resistance, and why? Which would have the highest resiliency, and why?

18. What are some environmental concerns that arise from the development of golf courses, and

how can they be addressed?

1 Andrew Knoll, Life on a Young Planet: The First Three Billion Years of Evolution on Earth (Princeton University

Press, 2003), p. 23.

APES Video Questions 3B

Watch “Bozeman Biology: Biogeochemical Cycling” (www.youtube.com/watch?v=09_sWPxQymA)





Focus Questions:

1. How do the unique properties of each element in CHONPS allow life to build complex

structures?

2. Why are bacteria important to biogeochemical cycling?

3. Why is it significant that the phosphorous cycle lacks an airborne phase, unlike CHONS?


Article #1

Early Warning Signs

Rapid shifts are the hallmark of climate change, epileptic seizures, financial crises, and fishery

collapses. Deep mathematical principles tie these events together.

At a closed meeting held in Boston in October 2009, the room was packed with high-

flyers in foreign policy and finance: Henry Kissinger, Paul Volcker, Andy Haldane, and Joseph

Stiglitz, among others, as well as representatives of sovereign wealth funds, pensions, and

endowments worth more than a trillion dollars—a significant slice of the world’s wealth. The

session opened with the following telling question: “Have the last couple of years shown that our

traditional finance/risk models are irretrievably broken and that models and approaches from

other fields (for example, ecology) may offer a better understanding of the interconnectedness

and fragility of complex financial systems?”

Science is a creative human enterprise. Discoveries are made in the context of our creations: our

models and hypotheses about how the world works. Big failures, however, can be a wake-up call

about entrenched views, and nothing produces humility or gains attention faster than an event

that blindsides so many so immediately.

Examples of catastrophic and systemic changes have been gathering in a variety of fields,

typically in specialized contexts with little cross-connection. Only recently have we begun to

look for generic patterns in the web of linked causes and effects that puts disparate events into a

common framework—a framework that operates on a sufficiently high level to include geologic

climate shifts, epileptic seizures, market and fishery crashes, and rapid shifts from healthy

ecosystems to biological deserts.

The main themes of this framework are twofold: First, they are all complex systems of

interconnected and interdependent parts. Second, they are nonlinear, non-equilibrium systems

that can undergo rapid and drastic state changes.

Consider first the complex interconnections. Economics is not typically thought of as a global

systems problem. Indeed, investment banks are famous for a brand of tunnel vision that focuses

risk management at the individual firm level and ignores the difficult and costlier, albeit less

frequent, systemic or financial-web problem. Monitoring the ecosystem-like network of firms

with interlocking balance sheets is not in the risk manager’s job description. Even so, there is

emerging agreement that ignoring the seemingly incomprehensible meshing of counterparty

obligations and mutual interdependencies (an accountant’s nightmare, more recursive than

Abbott and Costello’s “Who’s on first?”) prevented real pricing of risk premiums, which helped

to propagate the current crisis.

A parallel situation exists in fisheries, where stocks are traditionally managed one species at a

time. Alarm over collapsing fish stocks, however, is helping to create the current push for

ecosystem-based ocean management. This is a step in the right direction, but the current

ecosystem simulation models remain incapable of reproducing realistic population crashes. And

the same is true of most climate simulation models: Though the geological record tells us that

global temperatures can change very quickly, the models consistently underestimate that

possibility. This is related to the next property, the nonlinear, non-equilibrium nature of systems.

Most engineered devices, consisting of mechanical springs, transistors, and the like, are built to

be stable. That is, if stressed from rest, or equilibrium, they spring back. Many simple ecological

models, physiological models, and even climate and economic models are built by assuming the

same principle: a globally stable equilibrium. A related simplification is to see the world as

consisting of separate parts that can be studied in a linear way, one piece at a time. These pieces

can then be summed independently to make the whole. Researchers have developed a very large

tool kit of analytical methods and statistics based on this linear idea, and it has proven invaluable

for studying simple engineered devices. But even when many of the complex systems that

interest us are not linear, we persist with these tools and models. It is a case of looking under the

lamppost because the light is better even though we know the lost keys are in the shadows.

Linear systems produce nice stationary statistics—constant risk metrics, for example. Because

they assume that a process does not vary through time, one can subsample it to get an idea of

what the larger universe of possibilities looks like. This characteristic of linear systems appeals

to our normal heuristic thinking.

Nonlinear systems, however, are not so well behaved. They can appear stationary for a long

while, then without anything changing, they exhibit jumps in variability—so-called

“heteroscedasticity.” For example, if one looks at the range of economic variables over the past

decade (daily market movements, GDP changes, etc.), one might guess that variability and the

universe of possibilities are very modest. This was the modus operandi of normal risk

management. As a consequence, the likelihood of some of the large moves we saw in 2008,

which happened over so many consecutive days, should have been less than once in the age of

the universe.

Our problem is that the scientific desire to simplify has taken over, something that Einstein

warned against when he paraphrased Occam: “Everything should be made as simple as possible,

but not simpler.” Thinking of natural and economic systems as essentially stable and

decomposable into parts is a good initial hypothesis, current observations and measurements do

not support that hypothesis—hence our continual surprise. Just as we like the idea of constancy,

we are stubborn to change. The 19th century American humorist Josh Billings, perhaps, put it

best: “It ain’t what we don’t know that gives us trouble, it’s what we know that just ain’t so.”

So how do we proceed? There are a number of ways to approach this tactically, including new

data-intensive techniques that model each system uniquely but look for common characteristics.

However, a more strategic approach is to study these systems at their most generic level, to

identify universal principles that are independent of the specific details that distinguish each

system. This is the domain of complexity theory.

Among these principles is the idea that there might be universal early warning signs for critical

transitions, diagnostic signals that appear near unstable tipping points of rapid change. The

recent argument for early warning signs is based on the following: 1) that both simple and more

realistic, complex nonlinear models show these behaviors, and 2) that there is a growing weight

of empirical evidence for these common precursors in varied systems.

A key phenomenon known for decades is so-called “critical slowing” as a threshold approaches.

That is, a system’s dynamic response to external perturbations becomes more sluggish near

tipping points. Mathematically, this property gives rise to increased inertia in the ups and downs

of things like temperature or population numbers—we call this inertia “autocorrelation”—which

in turn can result in larger swings, or more volatility. In some cases, it can even produce

“flickering,” or rapid alternation from one stable state to another (picture a lake ricocheting back

and forth between being clear and oxygenated versus algae-ridden and oxygen-starved). Another

related early signaling behavior is an increase in “spatial resonance”: Pulses occurring in

neighboring parts of the web become synchronized. Nearby brain cells fire in unison minutes to

hours prior to an epileptic seizure, for example, and global financial markets pulse together. The

autocorrelation that comes from critical slowing has been shown to be a particularly good

indicator of certain geologic climate-change events, such as the greenhouse-icehouse transition

that occurred 34 million years ago; the inertial effect of climate-system slowing built up

gradually over millions of years, suddenly ending in a rapid shift that turned a fully lush, green

planet into one with polar regions blanketed in ice.

The global financial meltdown illustrates the phenomenon of critical slowing and spatial

resonance. Leading up to the crash, there was a marked increase in homogeneity among

institutions, both in their revenue-generating strategies as well as in their risk-management

strategies, thus increasing correlation among funds and across countries—an early warning.

Indeed, with regard to risk management through diversification, it is ironic that diversification

became so extreme that diversification was lost: Everyone owning part of everything creates

complete homogeneity. Reducing risk by increasing portfolio diversity makes sense for each

individual institution, but if everyone does it, it creates huge group or system-wide risk.

Mathematically, such homogeneity leads to increased connectivity in the financial system, and

the number and strength of these linkages grow as homogeneity increases. Thus, the

consequence of increasing connectivity is to destabilize a generic complex system: Each

institution becomes more affected by the balance sheets of neighboring institutions than by its

own. The role of systemic risk monitoring, then, could simply be rapid detection and

dissemination of potential imbalances, much as we allow frequent underbrush fires to burn in

order to forestall catastrophic wildfires. Provided that these kinds of imbalances can be rapidly

identified, maybe we will need no regulation beyond swift diffusion of information. Having

frequent, small disruptions could even be the sign of a healthy, innovative financial system.

Further tactical lessons could be drawn from similarities in the structure of bank payment

networks and cooperative, or “mutualistic,” networks in biology. These structures are thought to

promote network growth and support more species. Consider the case of plants and their insect

pollinators: Each group benefits the other, but there is competition within groups. If pollinators

interact with promiscuous plants (generalists that benefit from many different insect species), the

overall competition among insects and plants decreases and the system can grow very large.

Relationships of this kind are seen in financial systems too, where small specialist banks interact

with large generalist banks. Interestingly, the same hierarchical structure that promotes

biodiversity in plant-animal cooperative networks may increase the risk of large-scale systemic

failures: Mutualism facilitates greater biodiversity, but it also creates the potential for many

contingent species to go extinct, particularly if large, well-connected generalists—certain large

banks, for instance—disappear. It becomes an argument for the “too big to fail” policy, in which

the size of the company’s Facebook network matters more than the size of its balance sheet.

To be sure, bailing out a large financial institution raises questions of “moral hazard.” The more

compelling reason for caution, however, is that this action could propagate another systemic

collapse elsewhere in the network if there is too much focused subsidy and the benefit is not

spread out (a relevant point for those who are dispensing TARP funds). Excessively favorable

terms between two cooperating agents—say, the Fed and a large financial institution—can lead

to the unintended collapse of other agents and to eventual duopoly.

Another good example is the interdependence of the online auction site eBay and e-payment

system PayPal. PayPal was the dominant method of payment for eBay auctions when eBay

bought it in 2002, strengthening cooperative links between the two companies. This duopolistic

partnership contributed to the demise of competing payment systems, such as eBay’s Billpoint

(phased out after the purchase of PayPal), Citibank’s c2it (closed in 2003), and Yahoo!’s

PayDirect (closed in 2004).

As a final thought, as much as we would like to predict and manage catastrophic change, some

will be inevitable. Instability is a fact of nature. And hard as it may now be to believe,

displacements from climate change will one day dwarf our worries about the economy. As we

become increasingly aware of the ways in which our actions are speeding us toward climate

tipping points, perhaps our greatest asset will be our ability to anticipate these changes soon

enough to avoid them or, at the very least, prepare for their consequences.

Analysis Questions for “Early Warning Signs”

1. Why are humans especially prone to underestimating the speed, scale and nature of

changes in complex systems?

2. What do events as different as the recent economic crisis, climate change and ecosystem

disruptions have in common from a systems analysis perspective?

3. What is the difference between linear systems and nonlinear systems? Which ones are

more complex and unpredictable, and why?

4. What properties lead to systems being more vulnerable to a dramatic shift, such as a

collapse or a transition from one stable state to another?

5. What can we learn from this study of complex system dynamics to help us better

understand, manage and respond to changes in natural systems?

Article #2: From Scientific American - "Ecosystems on the Brink"

Analysis Questions:

1. Why did the addition of largemouth bass so dramatically transform Peter Lake? Describe

the changes that occurred and why a small change caused such a large systemic shift.

2. Why is it advantageous to represent food webs as complex mathematical systems that can

be simulated on a computer? How can this be done? And what makes this difficult?

3. How can human actions produce dramatic changes in natural systems so quickly, and

what are some examples?

4. What are some of the common signs of a system that is close to a tipping point? How can

this information help us?



Article #3 from National Geographic: "Fixing the Global Nitrogen Problem"

Analysis Questions:

1. Explain what the Haber-Bosch process is, and why it is so significant.

2. Describe a situation in which Nitrogen can be extremely beneficial, and one in which it

can be extremely harmful. How can one element play both a helpful and harmful role?

3. What is Nitrogen’s role in climate change and biodiversity loss?

4. What are the most important solutions to the “global nitrogen problem”?



unit 2: systems and cycles in nature

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