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

3
continue

• 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

4
continue

• 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.

5
continue

• 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.

6
continue

• 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

9
continue

• 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.

11
continue...

• 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

12
continue...

• 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.

18
continue...

• 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.

19
continue...

• 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)

20
continue..

• 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
  ?

22
continue...

• 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
continue...

• 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.

24
continue...

• 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)

25
continue...

• 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.

26
continue...

• 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

28
continue...

• 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.

29
continue...

• 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.

30
continue...

• 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
continue...

• 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.