Lecture 1 ns 5 ecology and ecosystem concepts 2010

1INTRODUCTION TO
ECOLOGY and
ECOSYSTEM CONCEPTS

Case Study: Deformity and Decline in Amphibian Populations

• High incidence of deformities in
amphibians
• Declining populations of amphibians
worldwide
• ECOLOGISTS’ ROL E IS TO FIND
ANSWERS:
 Amphibian population declines
were recent.
 Many declining populations
were in pristine or protected
areas.
 Amphibians are “biological
indicators” of environmental
problems
Figure 1.1 Deformed Leopard Frogs

faculty.sxu.edu/~cochran/ecoweb09/ecointro.ppt

HUMANS & ECOLOGY…

• Humans have enormous impact on the
planet.
• Humans are part of global environment.
• We must understand how natural
systems work.
• Ecology is the field of Biological
Science that studies the functions of
natural systems.

WHAT ECOLOGY IS….AND IS NOT
• Ecology is not “Environmentalism”
• Ecology is not “Natural History”
• Ecology is a Science
 “The study of the patterns and
processes that determine the
distribution and abundance of
organisms.”
 Based on observations,
hypotheses, empirical tests, theory,
models and more tests!

ECOLOGISTS VS NATURALIST VS ENVIRONMENTALISTS

Example: Consider the • Naturalist: Observes robins
American Robin, Turdus and paints/photographs/
migratorius writes/composes music
about robins. Provides
valuable “Natural History.”
• Ecologist: Asks, “What
causes the robin’s singing
behavior? Seeks to
explain the Natural History.
• Environmentalist: Seeks
action to preserve the
habitat of the robin.


Ecology is the scientific study of interactions
between organisms and their environment.

Ecology is a branch of biology.
Environmental science incorporates
concepts from the natural sciences
(including ecology) and the social
sciences, and focuses on solutions to
environmental problems.

Ernst Haeckel (1869) & ECOLOGY
• The scientific study of the interactions
between organisms and their environments
• “By ecology we mean the body of
knowledge concerning the economy of
Nature - the investigation of the total
relations of the animal to its inorganic and
organic environment.”
• The leading German disciple of Charles
Darwin
• Originally used the Greek spelling
Oecologie, and defined it as “the science of
the relations of living organisms to the
external world, their habitat, customs,
energies, parasites, etc.”

FROM OECOLOGIE TO ECOLOGY…

• Haeckel derived the new label from the same
root found in the older word
“economy” (“Oekonomie”):
 the Greek oikos, referring originally to the
family household and its daily operations
and maintenance
• The reason was that at that time, people
thought that national economic affairs could be
understood as an extension of the
housekeeper’s budget.
 Haeckel thought that the Earth constituted a
single economic unit

COINING THE TERM…

• Burdon-Sanderson (1890s):
Elevated Ecology to one of the three
natural divisions of Biology:
Physiology - Morphology – Ecology
Andrewartha (1961): “The scientific
study of the distribution and
abundance of organisms.”
• Odum (1963): “The structure and
function of Nature.”

TO STANDARDIZE OUR DEFINITION…

• Charles Krebs. Studies
migration and population
dynamics in lemmings and
other small mammals.
• (1972) Ecology is the scientific
study of the interactions that
determine the distribution and
abundance of organisms.

THUS…
• the study of the interactions between organisms and
their environment
• the study of the distribution and abundance of
organisms
• KEY POINTS:
• Interactions - between everyone and everything
• Organisms - all taxa are fair game
• Environment - includes ABIOTIC and BIOTIC factors
outside the organism
• Abundance - population sizes
• Distribution - where we find organisms?

Official ESA Definition*

• Ecology is “The scientific discipline that
is concerned with the relationships
between organisms and their past,
present and future environments, both
living and non-living.”
 Understanding these relationships will
explain the patterns of distribution and
abundance
* August 2000 Annual Meeting of the Ecological Society of America

WHY STUDY ECOLOGY?
• Curiosity – How does the world around us work? How are we
shaped by our surroundings?
• Responsibility – How do our actions change our environment?
How do we minimize the detrimental effects of our actions?
Overfishing, habitat destruction, loss of biodiversity, climate
change.
• Nature as a guide – The living world has been around much
longer than we have and has solved many problems with
creative solutions. Ecological systems are models for
sustainability. How can we feed our growing population?
Where will we live?
• Sustainability – a property of human society in which
ecosystems (including humans) are managed such that the
conditions supporting present day life on earth can continue.
• Ecology helps us understand complex problems.

The Earth environment is the home (habitat) of all forms of life including humans.
All life forms depend on the proper functioning of our environment!

ECOSYSTEM – basic unit and probably the most
important concept in ecology

Two Types of
System:
1. Open system –
presence of inputs
and outputs (matter
and energy)

2. Closed system –
no exchange of
matter and energy
(usually artificially
made, e.g.
terrarium)

ECOSYSTEM

• an ecosystem consists of all the
organisms and the abiotic pools with
which they interact (Chapin)
• an ecosystem is the sum of all of the
biological and nonbiological parts of
an area that interact to cause plants
to grow and decay, soil or sediments
to form, and the chemistry of water to
change (John Aber and Jerry Melillo)

EXAMPLE OF ECOSYSTEMS (CLOSED AND OPEN)

Controls over ecosystem processes: state factors, interactive
controls, and feedbacks

STATE FACTORS

• State factors set boundary conditions –
Hans Jenny (1941)
 Climate – broad geographic influence
on biome distribution
 Parent material – local influence on soil
type
 Potential biota – what organisms can
occupy a site
 Topography – microclimate
 Time – evolution, weathering

INTERACTIVE FACTORS

• Interactive controls: factors that both control
and are controlled by ecosystem
characteristics.
 Resources: energy and materials used to
support organisms’ growth and maintenance
 Modulators: physical and chemical
properties that affect organisms’ activity, but
are neither ‘consumed’ nor depleted
 Disturbance, Biotic Community, Human
Activities

FEEDBACKS
• negative feedbacks – homeostasis – when two components of a
system have opposite effects on one another
 predator – prey

 Thermostat

• positive feedbacks – when two components of a system have the
same effect (positive or negative) on each other
 runaway greenhouse effect – rising CO2 increases

temperature, increasing respiration, increasing CO2
 legumes and Rhizobium in nitrogen-fixing mutualisms –
each provides key resource to the other
• IN GENERAL:
 Negative feedbacks are key to maintaining ecosystems in a
given state, because they resist change
 Positive feedbacks, if unchecked, have the potential to shift
ecosystems from one state to another

BIOTIC COMPONENTS ABIOTIC COMPONENTS
 Producers  Climatic Factors
 Green Plants  Light
 Algae (Phytoplankton)  Temperature
 Consumers  Precipitation
 Herbivores  Wind
 Carnivores  Humidity
 Omnivores  Edaphic Factors
 Decomposers  Soil Nutrients
 Detritivores  Soil Moisture
 True decomposers  Soil Ph
 Bacteria and fungi  Hydrological Factors
 Physicochemical factor

FOUR LAWS OF ECOLOGY

1. EVERYTHING IS CONNECTED TO
EVERYTHING ELSE

2. EVERYTHING MUST GO SOMEWHERE

3. NATURE KNOWS BEST

4. THERE IS NO FREE LUNCH

1
NEXT MEETING: ENERGY
FLOWS IN AN ECOSYSTEM

MINI SKIT TIME….

Lecture 1 ns 5 ecology and ecosystem concepts 2010

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Lecture 1 ns 5 ecology and ecosystem concepts 2010