Ecology
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What is ecology?
The study of the interaction of living things
with:
– Each other
– Physical environment
From Greek
– “oikos” - the family household
– “logy” - the study of
– Same root as economics - management of
the household
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DEFINITIONS OF ECOLOGY
• The scientific study of the relationship
between organisms and their
environments
• From Ernest Haeckel (1866)
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Ecology Definition
“Ecology is the scientific discipline that is
concerned with the relationships between
organisms and their past, present, and
future environments.”
Source: Ecological Society of America
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Ecology tries to answer the following three
questions:
• Where are organisms found?
• How many occur there?
• Why?
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What is “the environment”?
It includes abiotic factors (e.g. climate) as
well as biotic factors (individuals of the
same and other species).
More precisely, the interaction between
abiotic and biotic factors happens within
the context of an ecosystem.
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What is an organism/what is life?
7 Life characteristics
– Organization
– Acquire materials and energy
– Homeostasis
– Growth
– Respond to stimuli
– Reproduce
– Adapt
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Levels of Organization
• Ecologist study
organisms ranging
from the various
levels of
organization:
– Individual
– Population
– Community
– Ecosystem
– Landscape
– Region
– Biosphere 8
© 2008 McGraw-Hill Ryerson Ltd.
© 2008 McGraw-Hill Ryerson Ltd.
Ecology is interdisciplinary
New areas of ecology
• Conservation ecology
• Restoration ecology
• Global ecology
• Landscape ecology
• Human ecology
• Ecological engineering
• Ecological economics
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Ecology courses
Chemical (Chemical ecology)
Animal (Animal ecology)
Community (Community ecology)
Population (Ecology of populations)
Wildlife (Wildlife ecology)
Conservation (Conservation biology)
Behavioral (Behavioral ecology)
Ecosystem (Ecosystem ecology) 13
SPATIAL SCALES IN ECOLOGY
Can be very large, e.g.:
• How do changes in ocean currents affect
fisheries?
• How will climate change affect distribution of
vegetation zones?
Can be very small, e.g.:
• How do different parasites within a single host cell
interact?
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TIME SCALES IN ECOLOGY
Can be very long, e.g.:
• How have North American vegetation zones
changed since the end of the last glaciation over
10,000 years ago?
Can be very short, e.g.:
• How quickly do bacteria re-colonize the human
gut after an antibiotic has been taken?
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ECOLOGY IS A SCIENCE
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What is science?
Continual process of refining or
rejecting hypotheses
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Hypothesis
• An educated guess
• A statement of cause and effect that can be tested
• Example: plant productivity is a linear function of soil
nitrogen content
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Testing hypotheses
• Design experiment
(key is to avoid confounding factors)
• Conduct experiment
• Analyze data
• Draw conclusion, accept or reject
hypothesis
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Testing hypotheses
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Field experiment: subplots within fields received different amounts of nitrogen
Testing hypotheses
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Testing hypotheses
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Testing hypotheses
• We accept the hypothesis:
– plant productivity is a linear function of soil nitrogen
content
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TYPES OF ECOLOGICAL
STUDIES
1. Field observations
2. Field experiments / manipulations
3. Lab experiments
4. Mathematical models
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The Physical
Environment:
Climate
Outline:
• solar radiation and latitude
• seasonality
• atmosphere and the greenhouse effect
• temperature patterns
• wind and rainfall patterns
• climographs
Readings: Ch. 3
Climate = long-term average pattern of
weather at a locality
– Local, regional or global
– Temperature, water, light, wind
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Climograph
Note distribution
of biomes is
determined
mainly by
patterns of
temperature and
rainfall
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Solar radiation drives this Earth
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Photosynthetically active radiation (PAR)
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SHORT LONG
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Effect of latitude
Sunlight hitting the earth near the poles is spread out over a larger surface area than
that hitting the equator. As a result, mean temperatures tend to decrease with 32
increasing latitude.
Seasonal variations in sunlight and temperature
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Latitudinal trends in temperature are altered by elevational
effects and the effects of continental/marine environments 36
Imaginary non-rotating Earth
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Ocean currents
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Precipitation
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Convective precipitation
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Dry climates occur near 30o latitude
and near the poles. Tropical and
temperate regions tend to
experience more rainfall.
Moist air ascending
Dry air descending
Dry air descending
Moist air ascending
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Intertropical convergence zone
Where the NE trade winds meets the SW trade winds
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Produces the rainy/dry seasons
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Orographic precipitation
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Effect of mountains: orographic precipitation
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