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The Natural Environment and the Human Economy:

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Title: The Natural Environment and the Human Economy:


1
The Natural Environment and the Human Economy
  • An Ecological Perspective

2
The Biosphere and Human Economy
  • The following are key elements of the basic
    principles governing the nature, structure and
    function of the biosphere (hence, environmental
    resources) and the functional linkages
    (relationships) between the biosphere and the
    human economy

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  • Environmental resources or the biosphere is
    finite. Hence, environmental resources are
    scarce in absolute terms.
  • In nature, everything is related to everything
    else. Moreover, survival of the biosphere
    requires recognition of the mutual
    interdependencies among all the elements that
    constitute the biosphere

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  • At a functional level and from a purely physical
    viewpoint, the biosphere is characterized by a
    continuous transformation of matter and energy.
    Furthermore, the transformation of matter and
    energy are governed by some immutable natural
    laws.
  • Material recycling is essential for the growth
    and revitalization of all the subsystems of the
    biosphere, including the human economy.

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  • Granted that nothing remains constant in nature.
    Furthermore, changes in ecosystems do not appear
    to occur in an absolutely linear and predictable
    manner. However, measured in a geological time
    scale, the natural tendency of an ecological
    community (species of plants, animals and
    microorganisms living together) tends to be to
    progress from simple and unstable relationships
    (pioneer stage) to a more stable, resilient,
    diverse and complex community.

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  • The human economy is a subsystem of the biosphere
    and it would be dangerously misleading to view
    natural resources as just factors of production
    lying outside the confines of the larger system.
  • The natural disposition of the technological
    human has tended towards the simplification of
    the natural systems eventually leading toward
    less stable, resilient, and diverse ecological
    communities.

7
What is Ecology?
  • Ecology is a branch of science that
    systematically studies the relationships between
    living organisms and the physical and chemical
    environment in which they live.

8
Why Study Ecology?
  • to provide a broader and deeper understanding of
    the natural process by which natural resources
    are created and maintained
  • to understand some of the natural laws that
    impose limitations on the interaction of
    organisms (including humans) with their living
    and nonliving environment

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  • to show the specific ways in which human
    interaction with nature has been incompatible,
    and
  • to identify some of the important links between
    ecology and economics, two disciplines which are
    imperative for a holistic view of natural
    resource problems and issues.

10
ECOSYSTEM A Starting Point of Ecological Study
  • An ecosystem includes living organisms in a
    specified physical environment, the multitude of
    interactions between the organisms, and the
    non-biological factors in the physical
    environment that limit their growth and
    reproduction, such as air, water, minerals, and
    temperature.

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  • Major components of an ecosystem
  • Abiotic (nonliving) components
  • The atmosphere (air)
  • The hydrosphere (water)
  • The lithosphere (earth crust)
  • Biotic (living) component
  • Producers -- organisms capable of photosynthesis
  • Consumers -- herbivores and carnivores
  • Decomposers -- microorganism
  • The Biosphere Abiotic biotic Life

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  • Broadly viewed, the abiotic components of an
    ecosystem serve as
  • Habitat (space) and immediate source of water and
    oxygen to organisms.
  • Reservoir of the six most essential elements for
    life (C, O, H, N, S, P). These elements
    constitute 95 of living organisms and found in
    fixed amount.
  • An agent for material recycling!

13
Ecosystem Functions
  • Ecosystem function ? movement or transformation
    of matter and energy.
  • Requires constant flow of external energy
  • Solar radiation--fuels the natural ecosystem
  • The movements of matter and energy are
    represented by various forms of cycles.

14
The Biotic Cycle
  • Matter and energy flow in the biotic cycle (see
    Figure --)
  • The role of the producers
  • The role of the consumers
  • The role of the decomposers
  • Material recycling at the biotic cycle level
  • Material recycling is not 100 efficient

15
Implications
  • In a natural ecosystem, living and non-living
    matter has reciprocal relationships. For that
    matter, survival and proper ecosystem
    functioning dictate mutual interactions
    (interdependence) among organisms and between
    them and the abiotic environment.

16
Other well known cycles
  • Atmospheric Cycles -- carbon, nitrogen, sulfur,
    etc.
  • Geologic Cycle, recycling of phosphate
  • Hydrologic cycles
  • Biogeochemical cycles

17
Ecological Development
  • Ecological succession -- involves natural changes
    in the species composition (types of plants,
    animals, and micro-organisms) that occupy a given
    area over a period of time, as well as the
    changes that occur in ecosystem dynamics such as
    energy flow and nutrient cycling.

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  • Pioneer stage populated by a few species and
    simple interrelationships.
  • Climax stage stable and supports a large number
    of organisms with complex and diverse
    interrelationships.

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  • Does increasing diversity lead to ecological
    stability and resilience?
  • Stability refers to the ability of a natural
    ecosystem to return to its original condition
    after a change or disturbance.
  • Resilience of a system refers to the rate at
    which a perturbed system will return to its
    original state. (see next slide)

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  • The conventional wisdom seem to be that as
    succession proceeds there tends to be an increase
    in stability, resilience, diversity, and
    complexity.
  • However, some ecologists argue that the more
    interconnected the components of the system are,
    the less stable the system is likely to have
    major impacts on closely connected species,
    initiating a ripple effect through the system.

21
The Law of Matter and Energy
  • Why is it that natural ecosystems need to have a
    continuous flow of energy from an external source
    ?

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  • Definition of terms
  • Matter is defined as anything that occupies a
    space and has mass
  • Energy may be viewed as an entity that lack mass
    but contains the capacity for moving and/or
    transforming an object--capacity to do work.

23
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  • The First Law of Thermodynamics states that
    matter and energy can neither be created nor
    destroyed, only transformed.
  • We can never really throw matter away.
  • Or, everything must go somewhere.
  • In terms of quantity the total energy/matter in
    the universe is constant.

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  • The Second Law of Thermodynamics states that each
    time useful energy is converted or transformed
    from one state (or form) to another, there always
    is less useful energy available in the second
    state than there was in the second. (see next
    slide for implications)

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  • Implications of the Second Law
  • Energy varies in its quality or ability to do
    work.
  • In all conversion of energy to work, there will
    always be a certain waste or loss of energy
    quality. The principle of energy degradation or
    entropy is universal.
  • No perfect energy conversion system--limits on
    conventional energy conversion technology.

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  • Energy moves unidirectionally--from high to low
    temperature. By implication, we can never recycle
    energy.
  • This last point, clearly explains why the natural
    ecosystem requires continual energy flow from an
    external source.

27
The Basic Lessons of Ecology
  • The substance that we often identify as natural
    resources (air, water, food, minerals, valleys,
    mountains, forests, waterfalls, wilderness, etc.)
    evolved from a multitude of complex interactions
    of living and non-living organisms, that are
    powered by the energy from the sun over a period
    measured on geological time scale.
  • Hence, natural resources are not just factors of
    production

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  • The interactions among the elemental components
    of the biosphere are governed by three
    principles
  • First, all matter in the ecosphere is mutually
    linked. Hence, human economy cannot be viewed in
    isolation as the Circular Diagram model depicts
    it.

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  • Second, material recycling is essential for the
    growth and revitalization of all the components
    of the ecosphere. No such thing as waste in
    nature.
  • Third, the various components of the biosphere go
    through gradual process of developmental
    stages--from pioneer to climax.

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  • The biosphere cannot escape the fundamental laws
    of matter and energy
  • First law
  • natural resources are finite
  • pollution is an inevitable by-product of any
    transformation of matter-energy (including the
    human economy).
  • Second law
  • energy cannot be recycled
  • no perfect machine--limit on energy conversion
    technology

31
Humanity as the Breaker of Climaxes
  • Simplification of the Ecosystem
  • Monoculture and its implication--the case of the
    Irish Potato Famine
  • Creation of industrial pollution (waste)
  • Waste beyond ecological thresholds (carbon
    dioxide emission and global warming)
  • Waste that are new to the natural ecosystem
  • Introduction of envasive plant and animal species

32
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  • Introduction of evasive plant and animal species
  • The end result of all this is a decline in the
    productivity and diversity of the natural
    ecosystems.
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