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
ROOT CAUSES
• Global Warming
• Overpopulation
• Soil Erosion
• Overconsumption
• Desertification
• Inefficiency
• Air Pollution
• Greed
Eco Ethics (I)
FRONTIER SOCIETY ETHIC
SUSTAINABLE SOCIETY ETHIC
(= Planetary Management Worldview)
(= Earth-Wisdom Worldview, Stewardship
Ethic ?)
• Anthropocentric
• Ecocentric / Biocentric
• Low Synergy
------------------------------------------------------------------------------------The earth has unlimited resources.
• High Synergy
------------------------------------------------------------------------------------------The earth has finite resources.
When resources are depleted in
one area, just move to another
area.
We must prevent depletion by
recycling and developing renewable
resources.
The value of one’s life is
measured by the accumulation of
material things
The value of one’s life is more than
just the sum of one’s material
wealth
Eco Ethics (II)
Economics is everything. It can
all be boiled down to the cost of
materials, energy and labor.
The TRUE COST must include
those things on the left AND also
take into account the costs to the
ecosystem and our health.
Humans are not a part of
nature. We are above nature.
We are a part of nature, and
as such are subject to all of its
“rules”.
Nature is there for us to use
and conquer.
We are a part of nature. We
must work with and within it.
Human activities are expected
to produce waste and it must
be tolerated.
Waste is not to be tolerated or
excused. All things should be
recycled, reused, etc.
New technology and new laws
will solve our problems; the
majority can leave the
solutions to just a few.
While these things may help,
we must all be involved in the
solution 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 Function
a number representing the flow or exchange
between compartments (between variables) of a
model.
• Forcing Function
a 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:
• NEGATIVE
tends to keep things the same (at or near
the ‘set point’)
• POSITIVE
moves 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) SURVIVABILITY
medical advances which allow for more people to live to
reproductive maturity and / or to just live longer
• 3) FOOD AVAILABILITY
agricultural productivity, distribution networks, income
Building A Model For Population
Growth (II)
• 4) SOCIETAL INFLUENCES
Religion, Pride, Nationalism, Political Views, Economics, etc. can
influence whether or not large or small families are "in".
• 5) RESOURCE AVAILABILITY
Resources can affect the ability to develop and support technology
or to trade for technology and / or food necessary to support the
population.
• 6) ENVIRONMENT
Including 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 Society
populations 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 Society
populations sedentary; started about 10,000 years ago
• Subsistence
fed your own family; villages small, impacts a bit
larger 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 Society
a) EARLY --- 1760's to WWII
b) 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?