Introduction to Ecology
Ecology derives components from each of the
Four Big Ideas in Biology
Big Idea 1: The process of evolution drives the
diversity and unity of life
Big Idea 2: Biological systems utilize free energy and
molecular building blocks to grow to reproduce & to
maintain dynamic homeostasis
Big Idea 3: Living systems store, retrieve, transmit, and
respond to information essential to life processes
Big Idea 4: Biological systems interact, and these
systems and their interactions possess complex
properties. Big Idea 4 is where most of our study of ecology is found!
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Ecology Defined
• Ecology is the study of
organisms and their
interactions with their
environment.
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Levels of Organization
4
Types of Ecology
Ecologist use observations & experiments to
test explanations for distributions and
abundance of species.
1. Organismal ecology is the study of physiology and
behavior interacting with environmental challenges
2. Population ecology studies the factors impacting the
number of individuals of a species in an area
3. Community ecology is the study of how organisms
interact with each other and the environment
4. Ecosystem ecology studies the energy flow and
chemical cycling in a given area
Types of Ecology
Identify the category of ecological research that
would investigate each of the following questions.
1. How do trout select a mate?
(A)Organismal ecology
(B) Population ecology
(C) Community ecology
(D)Ecosystem ecology
Types of Ecology
Identify the category of ecological research that
would investigate each of the following questions.
1. How do trout select a mate?
(A)Organismal ecology
(B) Population ecology
(C) Community ecology
(D)Ecosystem ecology
Types of Ecology
Identify the category of ecological research that
would investigate each of the following questions.
2. What factors control photosynthetic productivity
in a tropical rainforest?
(A)Organismal ecology
(B) Population ecology
(C) Community ecology
(D)Ecosystem ecology
Types of Ecology
Identify the category of ecological research that
would investigate each of the following questions.
2. What factors control photosynthetic productivity
in a tropical rainforest?
(A)Organismal ecology
(B) Population ecology
(C) Community ecology
(D)Ecosystem ecology
Types of Ecology
Identify the category of ecological research that
would investigate each of the following questions.
3. What factors influence the diversity of species
that make up a rain forest?
(A)Organismal ecology
(B) Population ecology
(C) Community ecology
(D)Ecosystem ecology
Types of Ecology
Identify the category of ecological research that
would investigate each of the following questions.
3. What factors influence the diversity of species
that make up a rain forest?
(A)Organismal ecology
(B) Population ecology
(C) Community ecology
(D)Ecosystem ecology
Abiotic and Biotic Interactions:
The 1st Law of Thermodynamics
http://www.sci.uidaho.edu/scripter/geog100/lect/16-ecosystems-biomes/ecosystems-files/ecosystems.htm
12
Abiotic and Biotic Interactions
http://www.sci.uidaho.edu/scripter/geog100/lect/16-ecosystems-biomes/ecosystems-files/ecosystems.htm
13
Abiotic and Biotic Interactions
http://www.sci.uidaho.edu/scripter/geog100/lect/16-ecosystems-biomes/ecosystems-files/ecosystems.htm
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Abiotic and Biotic Interactions
Importance of Abiotic Factors
Not every organism can live
everywhere on Earth
Abiotic factors determine
which organisms can survive
where:
The Coral Reef is an
environment teaming with life,
but many organisms would
find this environment
unsuitable due to its abiotic
factors (too much water,
temperature, availability of
light, etc. )
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Importance of Biotic Factors
EXPERIMENT
W. J. Fletcher tested the effects of two algae-eating animals, sea urchins and limpets, on seaweed
abundance near Sydney, Australia. In areas adjacent to a control site, either the urchins, the limpets, or both were
removed.
Sea
urchin
Both limpets
and urchins
removed
80
60
Seaweed cover (%)
Seaweed cover (%)
100
Only
urchins
removed
Limpet
Only limpets removed
40
Control (both
urchins and
limpets present)
20
0
August
1982
February
1983
August
1983
February
1984
Removing both
limpets and
urchins or
removing only
urchins increased
seaweed cover
dramatically.
Almost no
seaweed grew
in areas where
both urchins and
limpets were
present, or where
only limpets were
removed.
Earth’s Climate Varies By Latitude & Season
And Is Changing Rapidly
Macroclimate
consists of patterns on
the global, regional,
and landscape level
Microclimate consists
of very fine patterns,
such as those
encountered by the
community of
organisms underneath
a fallen log
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Earth’s Climate Varies By Latitude & Season
And Is Changing Rapidly
• Seasonal variations of light and temperature
increase steadily toward the poles
• Seasonality at high latitudes is caused by the tilt of
Earth’s axis of rotation and its annual passage
around the sun
• Belts of wet and dry air straddling the equator shift
throughout the year with the changing angle of the
sun
• Changing wind patterns affect ocean currents
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•
Earth’s Climate Varies By Latitude & Season
And Is Changing Rapidly
• Global Climate Change
• Changes in Earth’s climate can profoundly
affect the biosphere
• One way to predict the effects of future global
climate change is to study previous change
• As glaciers retreated 16,000 years ago, tree
distribution patterns changed
• As climate changes, species that have difficulty
dispersing may have smaller ranges or could
become extinct
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Homeostasis
• Organisms must maintain homeostasis, a steady-state
internal environment, despite changes in the external
environment.
• Organisms respond to abiotic factors in 1of 2 ways:
1. Regulators maintain a nearly constant internal
environment, despite external conditions
2. Conformers allow internal environment to vary
- This occurs in organisms whose environments
remain relatively stable
LAURASIA
120° 80°
40°
80° 120°
120°80°
80° 120°
GONDWANALAND
135 million years ago
225 million years ago
NORTH AMERICA
EURASIA
AFRICA
120°80°
SOUTH
AMERICA
INDIA
MADAGASCAR
120°
120°
0°
40°
120°
AUSTRALIA
ANTARCTICA
65 million years ago
Present
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Historical Biogeography
Biogeography: Leopard Distribution
Biogeography: Leopard Distribution
• Leopards have the largest distribution
of any wild cat, occurring widely in
eastern and central Africa, although
populations have shown a declining
trend and are fragmented outside of
sub-Saharan Africa.
• Within sub-Saharan Africa, the species
is still numerous and even thriving in
marginal habitats where other large
cats have disappeared.
• But populations in North Africa may
be extinct… Why?
Factors affecting/limits organism distribution
• Dispersal – (3 types)
• Behavior
– Habitat selection
• **Biotic Factors
– Predation, symbiotic relationships, parasitism,
disease
• **Abiotic Factors
– Chemical - water, oxygen, salinity, pH, soil
nutrients
– Physical - Temp., Sunlight, Moisture
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Biogeography
• Serves as a starting point to understanding
limits on distribution of species
Species absent
because
Yes
Yes
Dispersal
limits
distribution?
Yes
No
No
No
Biogeography & Distribution of Species
• Serves as a starting point to understanding
limits on distribution of species
Species absent
because
Yes
Area inaccessible
or insufficient time
Yes
Dispersal
limits
distribution?
Yes
No
Behavior
limits
distribution?
No
No
Biogeography
• Serves as a starting point to understanding
limits on distribution of species
Species absent
because
Yes
Area inaccessible
or insufficient time
Yes
Habitat selection
Dispersal
limits
distribution?
Yes
No
Behavior
limits
distribution?
No
Biotic factors
(other species)
limit
distribution?
No
Biogeography
• Serves as a starting point to understanding
limits on distribution of species
Species absent
because
Yes
Area inaccessible
or insufficient time
Yes
Habitat selection
Dispersal
limits
distribution?
Yes
No
Behavior
limits
distribution?
No
Biotic factors
(other species)
limit
distribution?
No
Predation, parasitism,
competition, disease
Abiotic factors
limit
distribution?
Biogeography
• Serves as a starting point to understanding
limits on distribution of species
Species absent
because
Yes
Dispersal
limits
distribution?
Area inaccessible
or insufficient time
Yes
Habitat selection
Yes
No
Behavior
limits
distribution?
No
Biotic factors
(other species)
limit
distribution?
No
Predation, parasitism,
competition, disease
Chemical
factors
Water
Oxygen
Salinity
pH
Soil nutrients, etc.
Abiotic factors
limit
distribution?
Physical
factors
Temperature
Light
Soil structure
Fire
Moisture, etc.
Ecology: The Big Picture
1. Biological systems interact, and these
systems and their interactions possess
complex properties.
2. Abiotic and biotic factors influence
populations, communities, ecosystems, and
the biosphere.
3. Over time species have adapted, died, or
moved to more suitable environments.
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Created by:
Susan Ramsey
Virginia Advanced Study Strategies
Notable contributions by S. Meister