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Chapter 52
Section 1 & 2
What Does Ecology Do?
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Ecology
Reveals the richness of the biosphere
What is Ecology?
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Study of interactions between
organisms and the environment
Ecology
Has a long history as a descriptive
science & is a rigorous experimental
science
Organisms and the Environment
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The environment of any organism
includes:
Abiotic
Nonliving components
Biotic
Living components
Biota
All the organisms living in the
environment
What role does the Environment
play for organisms?
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Affects the distribution and
abundance of organisms
Kangaroos/km2
> 20
10–20
5–10
1–5
0.1–1
< 0.1
Limits of
distribution
Southern Australia has
cool, moist winters and
warm, dry summers.
Climate in northern Australia
is hot and wet, with seasonal
drought.
Red kangaroos
occur in most
semiarid and arid
regions of the
interior, where
precipitation is
relatively low and
variable from
year to year.
Southeastern Australia
has a wet, cool climate.
Tasmania
Ways Ecologists Study the
Environment
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Use:
Observations
Experiments
Subfields of Ecology
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Organismal Ecology
Studies how an organism’s structure,
physiology, and behavior meet the
challenges posed by the environment
(a) Organismal ecology. How do humpback whales
select their calving areas?
Subfields of Ecology
Cont’d
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Population Ecology
Concentrates mainly on factors that
affect how many individuals of a
particular species live in an area
(b) Population ecology.
What environmental
factors affect the
reproductive rate of
deer mice?
Subfields of Ecology
Cont’d
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Community Ecology
Deals with the whole array of
interacting species in a community
(c) Community ecology.
What factors influence
the diversity of species
that make up a
particular forest?
Subfields of Ecology
Cont’d
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Ecosystem Ecology
Emphasizes energy flow and
chemical cycling between biotic and
abiotic components
(d) Ecosystem ecology. What
factors control
photosynthetic
productivity in a temperate
grassland ecosystem?
Subfields of Ecology
Cont’d
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Landscape Ecology
Deals with arrays of ecosystems and
how they are arranged in a
geographic region
(e) Landscape ecology. To what extent do the trees lining the
drainage channels in this landscape serve as corridors of
dispersal for forest animals?
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Biosphere
• Is the global ecosystem,
• Sum of all the planet’s ecosystems
Ecology and Environmental
Issues
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Ecology provides the scientific
understanding underlying
environmental issues
Rachel Carson
Started
the modern
environmental
movement
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Ecologists follow the Precautionary
Principle
Humans need to be concerned with
how their actions affect the
environment
Section 52.2
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Concept 50.2: Interactions between
organisms and the environment limit
the distribution of species
Dispersion Patterns
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Many naturalists have noticed a
pattern of the ways plants and
animals are distributed
Palearctic
Nearctic
Tropic
of Cancer
(23.5N)
Oriental
Ethiopian
Equator
Neotropical
(23.5S)
Tropic of
Capricorn
Australian
Dispersal and Distribution
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Dispersal
• Movement of individuals away from
centers of high population density or
from their area of origin
• Leads to distribution of species
Species Transplants
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Species Transplants
Organisms that are intentionally
or accidentally relocated from
original distribution
How does this effect an
ecosystem?
Can disrupt the communities or
ecosystems causing a change in
food chain
Behavior and Habitat Selection
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A Few Thoughts
Some Organisms
• Do not occupy all of their potential
range
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Species distribution
• May be limited by habitat selection
behavior
Biotic Factors
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These affect the distribution of
organisms
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Interactions with other species
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Predation
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Competition
Abiotic Factors
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These affect the distribution of organisms
Temperature
Water
Sunlight
Wind
Rocks and soil
Salinity
Temperature
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Environmental Temperature
How does this effect distribution of
species?
It can change biological processes
Water
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How is water a factor that could
influence species distribution?
Sunlight
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How is sunlight a factor that could
influence species distribution?
Can influence photosynthesis
Development and behavior of
organisms sensitive to the
photoperiods can be altered
Wind
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How does wind effect different
species?
Amplifies the effects of temperature
on organisms
Rocks and Soil
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How are rocks and soil a factor that
could influence species distribution?
Limit the distribution of plants and
thus the animals that feed upon them
by:
Physical Structure
pH
Mineral composition
Climate
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Climate
• Is the prevailing weather conditions in a
particular area
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Four major abiotic components make
up climate:
Temperature
Water
Sunlight
Wind
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Climate patterns can be described on
two scales
Macroclimate
These are on the global, regional, and
local level
Microclimate
In certain locations
Mountain Tops, under a fallen log etc…
Global Climate Patterns
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Global Climate Patterns
Determined by the input of solar
energy
Location of Earth in space
How Global Climate
Is Determined
(Input of Solar Energy)
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Sunlight Intensity
• Plays a major part in determining the
Earth’s climate patterns
LALITUDINAL VARIATION IN SUNLIGHT INTENSITY
North Pole
60N
Low angle of incoming sunlight
30N
Tropic of
Cancer
Sunlight directly overhead
0 (equator)
Tropic of
Capricorn
30S
Low angle of incoming sunlight
60S
South pole
Figure 50.10
Atmosphere
How Global Climate
Is Determined Cont’d
(Location In Space)
SEASONAL VARIATION IN SUNLIGHT INTENSITY
60N
June solstice: Northern
Hemisphere tilts toward
sun; summer begins in
Northern Hemisphere;
winter begins in
Southern Hemisphere.
30N
0 (equator)
March equinox: Equator faces sun directly;
neither pole tilts toward sun; all regions on Earth
experience 12 hours of daylight and 12 hours of
darkness.
30S
Constant tilt
of 23.5
September equinox: Equator faces sun
directly; neither pole tilts toward sun; all
regions on Earth experience 12 hours of
daylight and 12 hours of darkness.
December solstice: Northern
Hemisphere tilts away from sun;
winter begins in Northern
Hemisphere; summer begins
in Southern Hemisphere.
How Global Climate
Is Determined Cont’d
GLOBAL WIND PATTERNS
Arctic
Circle
60N
Westerlies
30N
Northeast trades
Doldrums
0
(equator)
Southeast trades
30S
Westerlies
60S
Antarctic
Circle
Figure 50.10
Regional, Local, and Seasonal
Effects on Climate
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Various features of the landscape
contribute to local variations in
climate
What might be some of these?
Bodies of Water
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Oceans and their currents, and large
lakes
2 Air cools at
high elevation.
3 Cooler
air sinks
over water.
4 Cool air over water
moves inland, replacing
rising warm air over land.
1 Warm air
over land rises.
Mountains
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Mountains have a significant effect
on
The amount of sunlight reaching an
area
Local temperature
Rainfall
Mountain Effect Cont’d
1
2
As moist air moves in
off the Pacific Ocean and
encounters the westernmost
mountains, it flows upward,
cools at higher altitudes,
and drops a large amount
of water. The world’s tallest
trees, the coastal redwoods,
thrive here.
Farther inland, precipitation
increases again as the air
moves up and over higher
mountains. Some of the world’s
deepest snow packs occur here.
3
On the eastern side of the
Sierra Nevada, there is little
precipitation. As a result of
this rain shadow, much of
central Nevada is desert.
Wind
direction
East
Pacific
Ocean
Sierra
Nevada
Coast
Range
Seasonality
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The angle of the sun
• Leads to many seasonal changes in local
environments
June solstice: Northern
Hemisphere tilts toward
sun; summer begins in
Northern Hemisphere;
winter begins in
Southern Hemisphere.
SEASONAL VARIATION IN SUNLIGHT INTENSITY
March equinox: Equator faces sun directly;
neither pole tilts toward sun; all regions on Earth
60N
experience 12 hours of daylight and 12 hours of
30N
darkness.
0 (equator)
30S
Constant tilt
of 23.5
September equinox: Equator faces sun
directly; neither pole tilts toward sun; all
regions on Earth experience 12 hours of
daylight and 12 hours of darkness.
December solstice: Northern
Hemisphere tilts away from sun;
winter begins in Northern
Hemisphere; summer begins
in Southern Hemisphere.