BIOLOGY 157: LIFE SCIENCE: AN

ENVIRONMENTAL APPROACH (Systems & Ecosystems; Modeling; Environmental Crisis)

Systems and Planetary Organization

System:

an interconnected complex of parts and processes characterized by many cause-effect pathways

Subdividing our Planetary System (I)

• Environment - the influences / forces / conditions that surround an organism

Biotic vs. Abiotic

Macroenvironment vs. Microenvironment

• Habitat - physical place where an organism or a community lives

Macrohabitat vs. Microhabitat

Subdividing our Planetary System (II)

• Atmosphere - the gaseous envelope around the earth

• Hydrosphere - all the water on the earth

• Lithosphere - the earth’s crust

• Pedosphere - on land, the surface part of the lithosphere that has been modified by organisms (= the soil!)

• Biosphere - the “life layer”, a hybrid region consisting of those portions of the atmosphere, hydrosphere and lithosphere that can support life in an active form

Subdividing our Planetary System (III)

Subdividing our Planetary System (IV) Layers of the Atmosphere

JET STREAM

Subdividing our Planetary System (V)

• Biogeographic Realms - large areas (on land) characterized by their flora and fauna

• Biomes - an area (on land) whose biota is controlled by (and is in balance with) the climate and is distinguished by the dominance of certain plants and animals(?? Can you name some biomes ??)

• Ecosystems - a unit composed of the biota and the environment of a particular area(?? How many ecosystems on the earth ??)

Biogeographic Realms

Biomes

Environmental Problems vs.Root Causes

PROBLEMS

• Global Warming

• Soil Erosion

• Desertification

• Air Pollution

ROOT CAUSES

• Overpopulation

• Overconsumption

• Inefficiency

• Greed

Eco Ethics (I)

FRONTIER SOCIETY ETHIC(= Planetary Management Worldview)

• Anthropocentric

• Low Synergy--------------------------------------------------------------------------------------The earth has unlimited resources.

When resources are depleted inone area, just move to anotherarea.

The value of one’s life is measured by the accumulation ofmaterial things

SUSTAINABLE SOCIETY ETHIC(= Earth-Wisdom Worldview, Stewardship

Ethic ?)

• Ecocentric / Biocentric

• High Synergy--------------------------------------------------------------------------------------------The earth has finite resources.

We must prevent depletion byrecycling and developing renewableresources.

The value of one’s life is more than just the sum of one’s material wealth

Eco Ethics (II)Economics is everything. It canall be boiled down to the cost ofmaterials, energy and labor.

Humans are not a part ofnature. We are above nature.

Nature is there for us to use and conquer.

Human activities are expectedto produce waste and it mustbe tolerated.

New technology and new laws will solve our problems; themajority can leave thesolutions to just a few.

The TRUE COST must includethose things on the left AND alsotake into account the costs to theecosystem and our health.

We are a part of nature, andas such are subject to all of its“rules”.

We are a part of nature. We must work with and within it.

Waste is not to be tolerated orexcused. All things should berecycled, reused, etc.

While these things may help,we must all be involved in thesolution of problems.

Tragedy Of The Commons (I)

• Garrett Hardin

• The concept comes from the concept of common lands in medieval England.

• Is this idea coming back?

Tragedy Of The Commons (II)

Environmental Crisis ???

The ‘environmental crisis’ is real and it is VERY complex.

Why is it so complex?

• the ecosystem itself is very complex

• many environmental problems

• numerous root causes

• problems and / or root causes often interact

• problems and / or root causes often transcend political boundaries

• viable solutions may not be available AND even when available people may disagree on what, if anything, is to be done or how to best go about doing something

Solving Environmental Problems

• must identify the major factors involved

• must decide on a mode of action

• must be committed to the solution

• must allocate the necessary resources

Models / Modeling• When investigating something (e.g. as in an attempt to

solve some type of problem) one usually acquires a large amount of data. To try to make some sense from the many components to our problem we usually must construct some type of MODEL.

• DEFINITION - A Model is a physical or abstract representation of the structure of a real system.

• Some models may be quite simple while others may be quite complex.

• Models do NOT have to be mathematical but most will need to be if they are to be of any real use.

Examples Of Models (I)

The generalized equations shown below are examples from chemistry of very simple models.

• A + B C

• A + B C + D

Examples Of Models (II)

Examples Of Models (III)

Examples Of Models (IV)

Examples Of Models (V)(Text, chapter 15)

Parts Of A Model No matter how complex a model might appear,

there are, at most, three main components.

• Variable (= systems variable)a number representing the state of a particular component in the model

• Transfer Functiona number representing the flow or exchange between compartments (between variables) of a model.

• Forcing Functiona number representing the magnitude of some particular ‘thing’ which affects a system but is NOT affected back by the system (may be present or absent).

Feedback Loops In A System

The parts of a model (variables, etc.) are interconnected in various ways and usually have effects on each other. They form pathways. Some of these become FEEDBACK LOOPS. These loops can be:

• NEGATIVEtends to keep things the same (at or near the ‘set point’)

• POSITIVEmoves things away from the set point

Building A Model For Population Growth (I)

Factors which could account for increase / decrease in population size:

• 1) BIRTH RATE (a measure of fertility)the number of births is affected by the number of people present; nutritional status (famine or plenty of food); degree of medical technology as it might relate to treating infertility or to providing means of birth control

• 2) SURVIVABILITYmedical advances which allow for more people to live to reproductive maturity and / or to just live longer

• 3) FOOD AVAILABILITYagricultural productivity, distribution networks, income

Building A Model For Population Growth (II)

• 4) SOCIETAL INFLUENCESReligion, Pride, Nationalism, Political Views, Economics, etc. can influence whether or not large or small families are "in".

• 5) RESOURCE AVAILABILITYResources can affect the ability to develop and support technology or to trade for technology and / or food necessary to support the population.

• 6) ENVIRONMENTIncluding disasters such as droughts, floods, plagues, crop failure from pests, war, pollution, etc. - all can affect the ability to support a larger population

Building A Model For Population Growth (III)

Now, think for a minute how you would go about

connecting these. Remember some may connect to

quite a few. Then think about the magnitude (the

size or degree) of the effect that each would have.

Remember, we might have to add a few more factors

to this in order to make it a reasonably 'good' model.

HISTORY LEADING TO ENVIRONMENTAL PROBLEMS

To look at the development of the environmental

problem we might find it advantageous to look at

our 'roots'. That is to say we should look at the

evolution of our species and the development of

various major societal periods in the recent history

of Humans.

HUMAN preHISTORY

LUCY SKELETON

RECENT EVOLUTIONARY HISTORY LEADING TO MODERN HUMANS

• Dryopithecus (25mya) (Dawn Ape)• Australopithecus (4-5mya)• Homo habilis (2.5mya; 1st humans; 'Lucy')• Homo erectus (1.5mya)• Homo sapiens (0.2 mya) (= 200,000 ya)

• (Cromagnon or 'modern’ humans, about 40,000ya)

• In the last 40,000 years (or even a bit longer) it has been much more cultural and technological changes rather than physical (or mental) evolution that has accounted for the changes we see in humans and their societies.

HUMAN 'SOCIETAL' SYSTEMS (I)

• 1) Hunter-Gatherer Societypopulations more or less NOMADIC; more than 10,000 years ago; minimal impact due to small population size; minimal possessions, minimal resource use, thus also providing for minimal impact; slow pop. growth rate

• 2) Agricultural Societypopulations sedentary; started about 10,000 years ago

• Subsistencefed your own family; villages small, impacts a bitlarger than H-G but still generally minimal

• Surplus (starting approx. 5,000 years ago)allowed for or resulted in city formation, resource movement (depletion - pollution), changes in ideas, specialization, crafts, etc.

HUMAN 'SOCIETAL' SYSTEMS (II)

• 3) Industrial Societya) EARLY --- 1760's to WWIIb) LATE --- Post WWII

The use of resources, pollution, dislocations, population growth, etc. accelerates with each stage and it is not an arithmetic progression, but rather it is generally a logarithmic progression.

IMPACTS OF SOCIETIES

TO SOLVE OUR PROBLEMS

To solve our environmental problems (and possibly other types of problems as well) we need to:

• 1) adopt a high synergy sustainable society ethic

• 2) control population size

• 3) use resources wisely (reduce amounts required by using only where and when ‘necessary’ and by using only the amounts really ‘necessary’)

• 4) reuse and recycle

• 5) use renewable resources whenever possible (e.g. - solar energy instead of coal and oil)

ADDITIONAL things from chapter 15 for YOU to investigate

• 1) What does the EPA do?

• 2) What is Adaptive Management?

• 3) Compare and Contrast: Environmental Literacy and Environmental Policy

• 4) BEFORE THE NEXT CLASS: “Google” Wikipedia for the terms “wicked problem” and “precautionary principle”. What relationships might these have to the information in chapter 15?