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Chapter 5-Biomes
Patterns of Life
I.
Terrestrial Biomes
A. Introduction
1. Defined
a. similar climate
b. similar growth pattern
c. similar vegetation types
2. Knowing the global distribution
of biomes & why is essential to
the study of Ecology/Env.
Science
3. Biomes differ in
a. biological productivity
b. resilience to hardship
4. Human use of biomes based on
biological productivity
5. Restoration of biomes due to
biome conditions
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a. ex. Clear cut
forests/restore quick in
New England but not in
Siberia
b. ex. Grasslands differ in rate
of recovery
6. Important determinants in
biome distributuion
a. temp. and precipitation
which changes with
elevation
b. vertical zonation
c. Landforms-mts., winds,
ocean, etc.
7. Many biomes determined by
latitudes p. 101
B. Tropical moist forests are warm &
wet year-round
1. complex & highest biodiversity
2. Cloud forests p. 101
a. high in mountains
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3.
4.
5.
6.
b. vegetation wet year-round
~fog & mist
Tropical rainforests p. 100
a. abundant rainfall (80 inch)
b. warm to hot year round
Soil
a. old, thin, acidic & nutrient
poor
b. biodiversity high-75% all
insets & plants live in the
rainforest
nutrient cycles
a. 90% nutrients found in
organism
b. growth depends on rapid
decomposition
Removal of Tropical RF
a. thin soil layer cannot
maintain crops
b. high erosion due to rains
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c. if large area, cannot be
regrown by forest
encroachment
C. Tropical seasonal forests has dry
seasons
1. Periods of drought-trees
become drought-deciduous
2. Tropical Dry Forests
a. soils have more nutrients
b. appealing to humans
(habitat degradation)
c. Highly endangered-less
than 1% undisturbed
D. Tropical savannas and Tropical
grasslands are dry most of the
year
1. Too little rain to support
forests
2. Rainy season but not enough for
trees
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3. Dry season brings fires which
stops succession/rapid
regrowth
4. Long roots to search for water
during dry times & to resist
the wind
E. Deserts are HOT or COLD, but
always dry!
1. rain unpredictable and less than
10 inch/yr.
2. Plant adaptations
a. water-storing leaves & stems
b. thick epidermal layers to
prevent evaporation & salt
tolerance
c. drought-deciduous
d. bloom & set seeds quickly
during rain
3. most deserts mid-continents
away from water vapor from
oceans
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4. Rain shadows from mountains
cause deserts ( ex. Coastal
Chile=driest desert)
5. Antarctica=no precipitation
6. Animal adaptations
a. most nocturnal
b. obtain moisture from seeds
& plants
c. highly concentrated urine &
dry feces
7. fragile biome
a. difficult to recover
desecration
b. overgrazing on biome edge
~little soil erodes away & no
water retention
F. Temperate Grasslands have rich
soils
1. Plant adaptations
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a. deep roots to survive
drought, fire & temp
changes
b. Thick covering of dead
leaves, yearly, causes
organic rich soil
c. Many converted to farms
(overgrazing)
G. Temperate shrublands have summer
drought (Mediterranean) chaparral
1. evergreen shrubs, grassland,
scrub-oaks, drought-resistant
pines
2. Periodic fires=succession ongoing
3. Spring flowering profuse
4. Sometimes a HOTSPOT for
biodiversity
5. Man=habitat degradation
H. Temperate forests can be
evergreen or deciduous.
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1. Rainfall plentiful
2. Deciduous=lose leaves
a. spring ephemeral (shortlived) plants grow beneath
understory of forest
before they leaf-out
b. diverse fauna through the
seasons
c. regrowth is quick
(succession)
3. Coniferous forests (TAIGA)
a. wide range of temp. &
moisture
b. moisture frozen in winter &
hot areas have seasonal
drought
c. Plant adaptations
~Thin waxy leaves prevent
loss of moisture
I. Tundra can freeze in any month
1. Temp. below freezing most of
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2.
3.
4.
5.
6.
the year
Treeless
High altitudes or on
mountaintops
Growing season 2-3 months
(24 hr. sun)
Alpine tundra & Arctic Tundra
Alpine Tundra
a. plants in AT must guard
against strong UV light
~thickly pigmented
~Leathery leaves
b. Low diversity
c. Fauna migrates through area
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II. Marine ecosystems
A. Introduction
1. 75% of earth is water
2. Marine ecosystems contribute
to the terrestrial ecosystems
a. Photosynthesis gives us
oxygen
~algae
~phytoplankton
~greatest near coastlines
where there is more nutrients (N-Ph)
b. ocean currents
~spread biodiversity of
organisms
~spread photosynthetic
organisms
3. Deep ocean ecosystems
a. Plankton die-sink to bottom
(marine snow) supplies deep
ocean with beginning of
food chain
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b. Upwelling currents
circulate nutrients
4. Vertical stratification p. 107
a. light decreases with depth
-photic zone to 20 m
-rely on thermal energy
below 20 m
b. temperature decrease with
depth
-metabolism slow so they
grow slowly
-cold water holds more
oxygen so more productivity
c. pressure increases with
depth
5. Oceans are described by depth
& proximity to shore
a. Littoral-shoreline
b. Intertidal-between tides
c. Pelagic-open ocean
(epi/meso/bathy_
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d. Abyssal (4000m-6000m)
e. Hadal zone (below 6000m)
B. Open ocean communities vary from
surface to Hadal zone (very bottom)
1. Open ocean referred to as
biological desert because of low
productivity
2. Equatorial Pacific & Antarctica
oceans
a. high diversity
b. nutrients distributed by
currents
3. Sargasso Sea (western Atlantic)
a. free floating mats of brown
algae
b. high diversity (turtles, fish,
eels, etc.)
4. Deep-sea thermal vents
a. chemo & thermal synthesis
from heat vents
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b. microbes use sulfur to
synthesize
c. magma heats the vents
d. tubeworms, mussels,
microbes etc.
e. extreme temp 700 degrees
f. extreme pressure
C. Coastal zones support rich, diverse
biological communities
1. Shorelines vary with depth,
light, temp & nutrients
2. Estuaries rich in diversity due
to high nutrients
3. Dead zones due to
a. excess nutrients in the
water
b. increase in bacteria
c. decrease oxygen
4. Coral reefs
a. high diversity = huge
biological productivity
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b. reefs made by symbiotic
relationship with
-phtosynthetic algae
-coral (calcium rich
skeleton)
c. Reefs
-protect shoreline
-shelter organisms
d. needs
-sunlight
-warm water (zones of
tolerance small)
-low nutrients & not much
nutrient run off
e. Most endangered biome
-introduced pathogens &
predators
-global warming causes
coral bleaching ( no algae)
-2006 convention-1/3 of all
coral reefs destroyed
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-60% degraded & will
probably die by 2030
5. Sea-grass beds (eel grass
beds)-high diversity
a. live in shallow, warm, sandy
areas near reef
b. easily destroyed by
sediment
6. Mangroves (trees which grow in
saltwater)
a. calm, shallow, tropical
coastlines
b. help to stabilize shorelines
c. critical nurseries for fish,
shrimp, etc.
d. vulnerable to development,
sedimentation & overuse
e. benefits
-commercial timber
-spawn beds
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7. Estuaries (bays which empty
into sea)
a. fresh & saltwater mix
b. biologically diverse &
productive
c. rivers give muddy bottom
to support plants &
nutrients & sediment
d. 2/3 of marine fish &
shelffish rely on estuaries,
for spawning (reproduction)
e. Estuaries near big cities
-supports seafood to area
-ex. Chesapeake Bay
8. Tide Pools
a. depressions in rocky
shoreline which floods at
high tide & almost dries at
low tide
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b. wave action prevents plant
growth, or sediment
accumulation
c. cold temp. at high tide/not
dessicating at low tide
d. strong animal life
9. Barrier islands p. 109
a. low, narrow, sandy islands
which form parallel to
coastline
b. protect inlets/lagoons from
storms, waves, tides
c. mostly sand & beach
III. Freshwater ecosystems
A. Lakes have open water
1. vertical zonation p. 110
a. Littoral-shoreline (much
life)
b. Epilimnion-open water
(more life & algae)
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c. Thermocline-area
separating cold/warm water
d. Hypolimnion-low oxygen
e. Benthos-lowest oxygen
levels (anaerobic bacteria)
2. Local conditions affect aquatic
community
a. nutrients
b. suspended matter (affects
light availability)
c. depth
d. temperature
e. currents
f. bottom characteristics
(rocky, sand, mud)
g. internal currents
h. connection or isolation from
aquatic/terrestrial systems
B. Wetlands are shallow & productive
1. land surface saturated or
submerged part of the year
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2. Rich biodiversity
a. breeding & migrating
animals
b. less than 5% of land but
1/3 endangered animals
3. Flood storage of water
4. Filter & purifies water
5. Descriptions
a. Swamps=wetlands with
trees
b. Marshes=wetlands without
trees
c. Bogs=peat (acidic)
d. Fens= similar to bogs but
not acidic
6. May convert to terrestrial
community by succession
IV. Human disturbance
A. Man dominant
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1. destroyed ½ worlds terrestrial
ecosystems
2. Stops natural biological
productivity
3. Conservation International maps
human disturbance of natural world.
Table 5.1 p. 112
B. Biomes
1. Temperate Deciduous Forest
most dominated biome
2. Grasslands & rainforest highly
disturbed by man
a. intensive cultivation
exposes soil to erosion &
fertility loss
b. Prairies converted to
farmlands
c. Madagascar, Haiti lost 99%
of original land cover
3. Tundra & Arctic deserts least
disturbed
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4. Wetlands suffer severe losses
ex. Iowa lost 99% wetlands
New Zealand lost 90%
Portugal lost 70%
C. Hope for preservation
1. Take Environmental Science
Class for updates!! Awareness does bring
change!! 