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Title: This powerpoint is textdense to say the least, so it will serve as the lecture notes, too' Study que


1
This powerpoint is text-dense to say the
least, so it will serve as the lecture notes,
too. Study questions follow on the last slide.
2
BIOMES I. Climatic Determinants II. FORESTS A.
Tropical Rain Forest B. Tropical Dry Forest
3
BIOMES I. Climatic Determinants II. FORESTS A.
Tropical Rain Forest B. Tropical Dry Forest 1.
Abiotic Conditions
4
BIOMES I. Climatic Determinants II. FORESTS A.
Tropical Rain Forest B. Tropical Dry Forest 1.
Abiotic Conditions TEMP Uniformly warm annual
temp gt 20C little annual variation
5
BIOMES I. Climatic Determinants II. FORESTS A.
Tropical Rain Forest B. Tropical Dry Forest 1.
Abiotic Conditions TEMP Uniformly warm annual
temp gt 20C little annual variation RAINFALL
Extreme seasonality, with a pronounced dry
season.
6
BIOMES I. Climatic Determinants II. FORESTS A.
Tropical Rain Forest B. Tropical Dry Forest 1.
Abiotic Conditions TEMP Uniformly warm annual
temp gt 20C little annual variation RAINFALL
Extreme seasonality, with a pronounced dry
season. EVAPOTRANSPIRATIONAL STRESS high in dry
season water limiting.
7
BIOMES I. Climatic Determinants II. FORESTS A.
Tropical Rain Forest B. Tropical Dry Forest 1.
Abiotic Conditions TEMP Uniformly warm annual
temp gt 20C little annual variation RAINFALL
Extreme seasonality, with a pronounced dry
season. EVAPOTRANSPIRATIONAL STRESS high in dry
season water limiting. LIGHT Never limiting,
neither seasonally nor beneath a canopy.
8
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9
BIOMES I. Climatic Determinants II. FORESTS A.
Tropical Rain Forest B. Tropical Dry Forest 1.
Abiotic Conditions TEMP Uniformly warm annual
temp gt 20C little annual variation RAINFALL
Extreme seasonality, with a pronounced dry
season. EVAPOTRANSPIRATIONAL STRESS high in dry
season water limiting. LIGHT Never limiting,
neither seasonally nor beneath a canopy.
NUTRIENTS and CYCLING Cycling is seasonal.
Litter accumulates until rainy - then nutrients
recycled
10
BIOMES I. Climatic Determinants II. FORESTS A.
Tropical Rain Forest B. Tropical Dry Forest 1.
Abiotic Conditions 2. Biota
11
BIOMES I. Climatic Determinants II. FORESTS A.
Tropical Rain Forest B. Tropical Dry Forest 1.
Abiotic Conditions 2. Biota
Diverse, but less so than rain forests
12
  • BIOMES
  • I. Climatic Determinants
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • 1. Abiotic Conditions
  • 2. Biota
  • Diverse, but less so than rain forests
  • Structurally simple - four layers, fewer lianas,
    no giant canopy trees or emergents

13
  • BIOMES
  • I. Climatic Determinants
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • 1. Abiotic Conditions
  • 2. Biota
  • Diverse, but less so than rain forests
  • This diversity perpetuates the evolution of
    greater diversity (More niches for herbivores,
    predators, pathogens, parasites, etc.)
  • Structurally simple - four layers, fewer lianas,
    no giant canopy trees or emergents
  • Less remains, as a of original, than rainforest
    because it is so easily converted to agricultural
    land and soil fertility is better.

14
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15
  • BIOMES
  • I. Climatic Determinants
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest

16
  • BIOMES
  • I. Climatic Determinants
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • 1. Abiotic Conditions

17
  • BIOMES
  • I. Climatic Determinants
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • 1. Abiotic Conditions
  • TEMP seasonal but not extreme - moderated by
    coastal currents. Cool - 10C mean.

San Francisco
18
  • BIOMES
  • I. Climatic Determinants
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • 1. Abiotic Conditions
  • TEMP seasonal but not extreme - moderated by
    coastal currents. Cool - 10C mean.
  • RAINFALL High but seasonal - dry summer
    moderated by fogs

19
  • BIOMES
  • I. Climatic Determinants
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • 1. Abiotic Conditions
  • TEMP seasonal but not extreme - moderated by
    coastal currents. Cool - 10C mean.
  • RAINFALL High but seasonal - dry summer
    moderated by fogs
  • EVAPOTRANSPIRATIONAL STRESS low for most the
    year hot summer

20
  • BIOMES
  • I. Climatic Determinants
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • 1. Abiotic Conditions
  • TEMP seasonal but not extreme - moderated by
    coastal currents. Cool - 10C mean.
  • RAINFALL High but seasonal - dry summer
    moderated by fogs
  • EVAPOTRANSPIRATIONAL STRESS low for most the
    year hot summer
  • LIGHT Seasonally limiting in winter and under
    closed canopies.

21
  • BIOMES
  • I. Climatic Determinants
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • 1. Abiotic Conditions
  • TEMP seasonal but not extreme - moderated by
    coastal currents. Cool - 10C mean.
  • RAINFALL High but seasonal - dry summer
    moderated by fogs
  • EVAPOTRANSPIRATIONAL STRESS low for most the
    year hot summer
  • LIGHT Seasonally limiting in winter and under
    closed canopies.
  • SOILS deep, rich humus layer, rich A horizon.
    Slower decomposition and shallower bedrock keep
    nutrients at surface

22
  • BIOMES
  • I. Climatic Determinants
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • 1. Abiotic Conditions
  • TEMP seasonal but not extreme - moderated by
    coastal currents. Cool - 10C mean.
  • RAINFALL High but seasonal - dry summer
    moderated by fogs
  • EVAPOTRANSPIRATIONAL STRESS low for most the
    year hot summer
  • LIGHT Seasonally limiting in winter and under
    closed canopies.
  • SOILS deep, rich humus layer, rich A horizon.
    Slower decomposition and shallower bedrock keep
    nutrients at surface
  • DISTURBANCE winter, treefalls, storms

23
  • BIOMES
  • I. Climatic Determinants
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • 1. Abiotic Conditions
  • TEMP seasonal but not extreme - moderated by
    coastal currents. Cool - 10C mean.
  • RAINFALL High but seasonal - dry summer
    moderated by fogs
  • EVAPOTRANSPIRATIONAL STRESS low for most the
    year hot summer
  • LIGHT Seasonally limiting in winter and under
    closed canopies.
  • NUTRIENTS and CYCLING stalled by winter and dry
    summer, but otherwise wet .

24
  • BIOMES
  • I. Climatic Determinants
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • 2. Biota

25
  • BIOMES
  • I. Climatic Determinants
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • 2. Biota
  • Lower diversity, but tallest trees on the planet,
    in NA, hemlock and spruce in north give way to
    redwoods and sequoia in south

26
Redwood
27
  • BIOMES
  • I. Climatic Determinants
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • 2. Biota
  • Lower diversity, but tallest trees on the planet,
    in NA, hemlock and spruce in north give way to
    redwoods and sequoia in south
  • Also found in southern Chile and in SE
    Australia/New Zealand - tallest eucalyptus are
    tallest angiosperms.

28
Sequoia semperviren
Eucalyptus regnans
29
  • BIOMES
  • I. Climatic Determinants
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • 2. Biota
  • Lower diversity, but tallest trees on the planet,
    in NA, hemlock and spruce in north give way to
    redwoods and sequoia in south
  • Also found in southern Chile and in SE
    Australia/New Zealand - tallest eucalyptus are
    tallest angiosperms.
  • Structurally simple dark understory retards
    growth of understory except mosses... heavy
    epiphyte load

30
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31
  • BIOMES
  • I. Climatic Determinants
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • D. Temperate Deciduous Forest

32
  • BIOMES
  • I. Climatic Determinants
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • D. Temperate Deciduous Forest
  • 1. Abiotic Conditions

33
  • BIOMES
  • I. Climatic Determinants
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • D. Temperate Deciduous Forest
  • 1. Abiotic Conditions
  • TEMP Seasonality is more extreme, with more
    severely cold winters but moist spring and
    summer.

34
  • BIOMES
  • I. Climatic Determinants
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • D. Temperate Deciduous Forest
  • 1. Abiotic Conditions
  • TEMP Seasonality is more extreme, with more
    severely cold winters but moist spring and
    summer.
  • RAINFALL More even throughout year no
    pronounced drought period.

35
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36
  • BIOMES
  • I. Climatic Determinants
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • D. Temperate Deciduous Forest
  • 1. Abiotic Conditions
  • TEMP Seasonality is more extreme, with more
    severely cold winters but moist spring and
    summer.
  • RAINFALL More even throughout year no
    pronounced drought period.
  • EVAPOTRANSPIRATIONAL STRESS low for most the
    year hot summer but dry winter (frozen precip)

37
  • BIOMES
  • I. Climatic Determinants
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • D. Temperate Deciduous Forest
  • 1. Abiotic Conditions
  • TEMP Seasonality is more extreme, with more
    severely cold winters but moist spring and
    summer.
  • RAINFALL More even throughout year no
    pronounced drought period.
  • EVAPOTRANSPIRATIONAL STRESS low for most the
    year hot summer
  • LIGHT Seasonally limiting in winter and under
    closed canopies.

38
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39
  • BIOMES
  • I. Climatic Determinants
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • D. Temperate Deciduous Forest
  • 1. Abiotic Conditions
  • TEMP Seasonality is more extreme, with more
    severely cold winters but moist spring and
    summer.
  • RAINFALL More even throughout year no
    pronounced drought period.
  • EVAPOTRANSPIRATIONAL STRESS low for most the
    year hot summer
  • LIGHT Seasonally limiting in winter and under
    closed canopies.
  • NUTRIENTS and CYCLING Slow but efficient deep
    litter layer.

40
  • BIOMES
  • I. Climatic Determinants
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • D. Temperate Deciduous Forest
  • 1. Abiotic
  • 2. Biota

41
  • BIOMES
  • I. Climatic Determinants
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • D. Temperate Deciduous Forest
  • 1. Abiotic
  • 2. Biota
  • Deciduous trees dominate growing season long
    enough to grow new ones and still make enough
    photosynthetic profit to overwinter.

42
  • BIOMES
  • I. Climatic Determinants
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • D. Temperate Deciduous Forest
  • 1. Abiotic
  • 2. Biota
  • Deciduous trees dominate growing season long
    enough to grow new ones and still make enough
    photosynthetic profit to overwinter.
  • Simple four-layer structure to forest.

CANOPY UNDERSTORY SHRUB HERB
43
  • BIOMES
  • I. Climatic Determinants
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • D. Temperate Deciduous Forest
  • 1. Abiotic
  • 2. Biota
  • Deciduous trees dominate growing season long
    enough to grow new ones and still make enough
    photosynthetic profit to overwinter.
  • Simple four-layer structure to forest.
  • herbs flower in in spring when light abundant
    also when wind-dispersed canopy trees pollinate

44
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45
  • BIOMES
  • I. Climatic Determinants
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • D. Temperate Deciduous Forest
  • 1. Abiotic
  • 2. Biota
  • Deciduous trees dominate growing season long
    enough to grow new ones and still make enough
    photosynthetic profit to overwinter.
  • Simple four-layer structure to forest.
  • herbs flower in in spring when light abundant
    also when wind-dispersed canopy trees pollinate
  • Biota varies dramatically with climate, from
    northern hardwoods of Beech and Maple to Southern
    Poplar-Oak (moist) and Oak-Hickory (dry).

46
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47
  • BIOMES
  • I. Climatic Determinants
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • D. Temperate Deciduous Forest
  • 1. Abiotic
  • 2. Biota
  • Deciduous trees dominate growing season long
    enough to grow new ones and still make enough
    photosynthetic profit to overwinter.
  • Simple four-layer structure to forest.
  • herbs flower in in spring when light abundant
    also when wind-dispersed canopy trees pollinate
  • Biota varies dramatically with climate, from
    northern hardwoods of Beech and Maple to Southern
    Poplar-Oak (moist) and Oak-Hickory (dry).
  • Pines dominate early in succession, or on dry
    slopes, sandy soils, or other nutrient poor
    substrates.

48
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49
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • D. Temperate Deciduous Forest
  • E. Boreal Forest(Taiga)

50
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • D. Temperate Deciduous Forest
  • E. Boreal Forest(Taiga)
  • 1. Abiotic Conditions

51
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • D. Temperate Deciduous Forest
  • E. Boreal Forest(Taiga)
  • 1. Abiotic Conditions
  • TEMP A cold climate limits the growing season
    no "time" for broad leaved trees to make leaves
    and grow conifers dominate.Freeze-thaw cycles
    keep roots shallow

52
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • D. Temperate Deciduous Forest
  • E. Boreal Forest(Taiga)
  • 1. Abiotic Conditions
  • TEMP A cold climate limits the growing season
    no "time" for broad leaved trees to make leaves
    and grow conifers dominate.Freeze-thaw cycles
    keep roots shallow
  • RAINFALL Precip. is low (40-100 cm/year).

53
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • D. Temperate Deciduous Forest
  • E. Boreal Forest(Taiga)
  • 1. Abiotic Conditions
  • TEMP A cold climate limits the growing season
    no "time" for broad leaved trees to make leaves
    and grow conifers dominate.Freeze-thaw cycles
    keep roots shallow
  • RAINFALL Precip. is low (40-100 cm/year).
  • EVAPOTRANSPIRATIONAL STRESS Severe in long
    winter due to low water availability

54
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • D. Temperate Deciduous Forest
  • E. Boreal Forest(Taiga)
  • 1. Abiotic Conditions
  • TEMP A cold climate limits the growing season
    no "time" for broad leaved trees to make leaves
    and grow conifers dominate.Freeze-thaw cycles
    keep roots shallow
  • RAINFALL Precip. is low (40-100 cm/year).
  • EVAPOTRANSPIRATIONAL STRESS Severe in long
    winter due to low water avaiability
  • LIGHT Seasonally limiting in winter and under
    closed canopies.

55
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • D. Temperate Deciduous Forest
  • E. Boreal Forest(Taiga)
  • 1. Abiotic Conditions
  • TEMP A cold climate limits the growing season
    no "time" for broad leaved trees to make leaves
    and grow conifers dominate.Freeze-thaw cycles
    keep roots shallow
  • RAINFALL Precip. is low (40-100 cm/year).
  • EVAPOTRANSPIRATIONAL STRESS Severe in long
    winter due to low water avaiability
  • LIGHT Seasonally limiting in winter and under
    closed canopies.

56
Bogs - water accumulates at surface
Permafrost reduces root growth and plant growth
57
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • D. Temperate Deciduous Forest
  • E. Boreal Forest(Taiga)
  • 1. Abiotic Conditions
  • TEMP A cold climate limits the growing season
    no "time" for broad leaved trees to make leaves
    and grow conifers dominate.Freeze-thaw cycles
    keep roots shallow
  • RAINFALL Precip. is low (40-100 cm/year).
  • EVAPOTRANSPIRATIONAL STRESS Severe in long
    winter due to low water avaiability
  • LIGHT Seasonally limiting in winter and under
    closed canopies.
  • NUTRIENT CYCLING Slow and inefficient organic
    debris and water trapped at surface by ice,
    creates bogs

58
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • D. Temperate Deciduous Forest
  • E. Boreal Forest(Taiga)
  • 1. Abiotic Conditions
  • 2. Biota

59
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • D. Temperate Deciduous Forest
  • E. Boreal Forest(Taiga)
  • 1. Abiotic Conditions
  • 2. Biota
  • Slow growing (but evergreen) conifers dominate
    spruce, fir, pine. Birch and Aspen are only
    deciduous trees to make it.

60
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • D. Temperate Deciduous Forest
  • E. Boreal Forest(Taiga)
  • 1. Abiotic Conditions
  • 2. Biota
  • Slow growing (but evergreen) conifers dominate
    spruce, fir, pine. Birch and Aspen are only
    deciduous trees to make it.
  • Communities grade from sparse forest/tundra
    boundary with lichens, moss, and an occasional
    spruce to conifer forest to the white pine
    /hemlock/ northern hardwood transition with the
    deciduous forest.
  • dense brush in gaps otherwise no shrub layer to
    speak of

61
  • II. FORESTS
  • A. Tropical Rain Forest
  • B. Tropical Dry Forest
  • C. Temperate Rain Forest
  • D. Temperate Deciduous Forest
  • E. Boreal Forest(Taiga)
  • 1. Abiotic Conditions
  • 2. Biota
  • Slow growing (but evergreen) conifers dominate
    spruce, fir, pine. Birch and Aspen are only
    deciduous trees to make it.
  • Communities grade from sparse forest/tundra
    boundary with lichens, moss, and an occassional
    spruce to conifer forest to the white
    pine/hemlock/northern hardwood transition with
    the deciduous forest.
  • dense brush in gaps otherwise no shrub layer to
    speak of
  • dramatic seasonality to many animal populations

62
BIOMES I. Climatic Determinants II. FORESTS III.
Grasslands
63
III. Grasslands A. Shrub Forest Savannah
(Tropics) 1. Abiotic Conditions TEMP Uniformly
warm annual temp gt 20C a bit more seasonality
due to warmer temps during arid dry season
RAINFALL seasonal - closer to tropical margins
rainfall determines tree density, from shrub
forest ot tropical savannah with a few trees to
true grassland EVAPOTRANSPIRATIONAL STRESS
high, especially in dry season selects for C4
grasses LIGHT Never limiting, no winter and no
big trees creating shade NUTRIENTS and CYCLING
Most nutrients bound in biomass rapid
decomposition and rapid absorption. Little litter
accumulation.
64
III. Grasslands A. Shrub Forest Savannah
(Tropics) 1. Abiotic Conditions 2. Biota
65
III. Grasslands A. Shrub Forest - Savannah 1.
Abiotic Conditions 2. Biota Arid conditions and
fire select for C4 grasses
66
III. Grasslands A. Shrub Forest - Savannah 1.
Abiotic Conditions 2. Biota Arid conditions and
fire select for C4 grasses In "C3" metabolism,
the metabolism we have already learned, CO2 is
first bound to a C5 molecule - making an unstable
C6 molecule that splits into two C3
molecules...glucose is produced and the C5's are
recycled...
6(CO2)
6(C6)
6(C5)
C6 (Glucose)
5(C6)
67
III. Grasslands A. Shrub Forest - Savannah 1.
Abiotic Conditions 2. Biota Arid conditions and
fire select for C4 grasses In "C3" metabolism,
the metabolism we have already learned, CO2 is
first bound to a C5 molecule - making an unstable
C6 molecule that splits into two C3
molecules...glucose is produced and the C5's are
recycled...
6(CO2)
But there is a big problem when things get dry.
The plants close the pores in their leaves to
reduce water loss ('cuz it's dry!), and this
stops gas exchange, too. So no more CO2 gets
into the leaf, and no O2 can get out.
6(C6)
6(C5)
C6 (Glucose)
5(C6)
68
III. Grasslands A. Shrub Forest - Savannah 1.
Abiotic Conditions 2. Biota Arid conditions and
fire select for C4 grasses In "C3" metabolism,
the metabolism we have already learned, CO2 is
first bound to a C5 molecule - making an unstable
C6 molecule that splits into two C3
molecules...glucose is produced and the C5's are
recycled...
6(CO2)
But there is a big problem when things get dry.
The plants close the pores in their leaves to
reduce water loss ('cuz it's dry!), and this
stops gas exchange, too. So no more CO2 gets
into the leaf, and no O2 can get out. And so, as
photosynthesis proceeds in a closed leaf, CO2
decreases and the O2 increases.
6(C6)
6(C5)
C6 (Glucose)
5(C6)
69
III. Grasslands A. Shrub Forest - Savannah 1.
Abiotic Conditions 2. Biota Arid conditions and
fire select for C4 grasses In "C3" metabolism,
the metabolism we have already learned, CO2 is
first bound to a C5 molecule - making an unstable
C6 molecule that splits into two C3
molecules...glucose is produced and the C5's are
recycled...
O2
(CO2)
This is bad because the C5 molecule can only bind
CO2 when it's in high concentration. As the
CO2 drops, the C5 molecules bind to oxygen and
are metabolized... and glucose production
STOPS... (this is BAD).
6(C6)
6(C5)
C6 (Glucose)
5(C6)
C5 BREAKDOWN
70
III. Grasslands A. Shrub Forest - Savannah 1.
Abiotic Conditions 2. Biota Arid conditions and
fire select for C4 grasses In "c4" metabolism,
the C3 pathway is isolated in special cells, in
which the CO2 concentration can be kept high (so
that glucose production will continue).
6(CO2)
6(C6)
6(C5)
C6 (Glucose)
5(C6)
71
III. Grasslands A. Shrub Forest - Savannah 1.
Abiotic Conditions 2. Biota Arid conditions and
fire select for C4 grasses The CO2 conentration
is kept high by "pumping it in"... PEP is a C3
molecule that binds CO2 even at low
concentratrations (making a C4 molecule.
6(CO2)
CO2
6(C6)
C4
PEP (C3)
6(C5)
C6 (Glucose)
5(C6)
72
III. Grasslands A. Shrub Forest - Savannah 1.
Abiotic Conditions 2. Biota Arid conditions and
fire select for C4 grasses This C4 molecule is
transferred and broken releasing CO2 and
recycling PEP. So CO2 is high in the special
cell and glucose production continues.
6(CO2)
CO2
6(C6)
C4
6(C5)
C6 (Glucose)
PEP (C3)
PEP (C3)
5(C6)
73
III. Grasslands A. Shrub Forest - Savannah 1.
Abiotic Conditions 2. Biota Arid conditions and
fire select for C4 grasses SO, CO2 fixation is
spatially separate from Glucose production.
6(CO2)
CO2
6(C6)
C4
6(C5)
C6 (Glucose)
PEP (C3)
PEP (C3)
5(C6)
74
  • III. Grasslands
  • A. Shrub Forest - Savannah
  • 1. Abiotic Conditions
  • 2. Biota
  • Arid conditions and fire select for C4 grasses
  • Large grazers dominate harvest energy by
    processing huge amounts of forage quickly, or by
    ruminating (bacterial gut flora). Migratory

75
Cows are "foregut fermenters"... food goes
straight to a fermentation sac (rumen) with
bacteria....they regurgitate food and chew it
several times (chewing cud) before it passes to
the intestine for the extraction of nutrients...
76
Horses are "hindgut fermenters"... food goes to
the stomach and then to the intestine, with no
regurgitation. The large intestine a caecum
(blind sac) have bacteria that break down the
cellulose. They must eat pretty continuously
because they don't ectract as many nutrients from
the food they eat.
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78
III. Grasslands A. Shrub Forest - Savannah B.
Temperate Grassland (Prairie)
79
III. Grasslands A. Shrub Forest - Savannah B.
Temperate Grassland (Prairie) 1. Abiotic
80
III. Grasslands A. Shrub Forest - Savannah B.
Temperate Grassland (Prairie) 1. Abiotic TEMP
seasonal extremes - continental climate limits
growing season to 120-300 days depending on
latitude and temperature extremes. RAINFALL
Summer rain is predictably seasonal. Rainfall is
too low to leach cations from soil but can be
high enough to support significant plant
productivity. EVAPOTRANSPIRATIONAL STRESS high,
especially in dry season selects for C4 grasses
but C3 grasses still plentiful LIGHT Never
limiting, no winter and no big trees creating
shade NUTRIENTS and CYCLING moist grasslands
are richest soils on Earth, rich in nutrients and
organics
81
III. Grasslands A. Shrub Forest - Savannah B.
Temperate Grassland (Prairie) 1. Abiotic 2.
Biota
82
III. Grasslands A. Shrub Forest - Savannah B.
Temperate Grassland (Prairie) 1. Abiotic 2.
Biota The height and density of grasses
correlates with rainfall, which changes the soil
conditions.
increasing rainfall
83
III. Grasslands A. Shrub Forest - Savannah B.
Temperate Grassland (Prairie) 1. Abiotic 2.
Biota The height and density of grasses
correlates with rainfall, which changes the soil
conditions. Perennial C4 grasses dominate.
84
III. Grasslands A. Shrub Forest - Savannah B.
Temperate Grassland (Prairie) 1. Abiotic 2.
Biota The height and density of grasses
correlates with rainfall, which changes the soil
conditions. Perennial C4 grasses dominate.
Again, large grazers and predators dominate the
food webs.
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86
III. Grasslands A. Shrub Forest - Savannah B.
Temperate Grassland (Prairie) C. ArcticTundra
ALPINE
ARCTIC
87
III. Grasslands A. Shrub Forest - Savannah B.
Temperate Grassland (Prairie) C. Arctic Tundra 1.
Abiotic
88
III. Grasslands A. Shrub Forest - Savannah B.
Temperate Grassland (Prairie) C. Arctic Tundra 1.
Abiotic TEMP Cold most of the year, with a
growing season less than 100 days. The summer
does have long days, but light intensities are
still low due to oblique angle. RAINFALL
Precipitation is very low, less than 25cm/year.
EVAPOTRANSPIRATIONAL STRESS high, largely due
to desiccating effects of dry, strong cold winds
and water frozen as ice most of year. LIGHT
Limiting most of year growing season very short
SOILS shallow just above permafrost boggy in
summer very slow decomposition - mats of peat
that transfer little nitrogen to soil
89
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90
III. Grasslands A. Shrub Forest - Savannah B.
Temperate Grassland (Prairie) C. Arctic Tundra 1.
Abiotic TEMP Cold most of the year, with a
growing season less than 100 days. The summer
does have long days, but light intensities are
still low due to oblique angle. RAINFALL
Precipitation is very low, less than 25cm/year.
EVAPOTRANSPIRATIONAL STRESS high, largely due
to desiccating effects of dry, strong cold winds
and water frozen as ice most of year. LIGHT
Limiting most of year growing season very short

91
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92
III. Grasslands A. Shrub Forest - Savannah B.
Temperate Grassland (Prairie) C. Arctic Tundra 1.
Abiotic TEMP Cold most of the year, with a
growing season less than 100 days. The summer
does have long days, but light intensities are
still low due to oblique angle. RAINFALL
Precipitation is very low, less than 25cm/year.
EVAPOTRANSPIRATIONAL STRESS high, largely due
to desiccating effects of dry, strong cold winds
and water frozen as ice most of year. LIGHT
Limiting most of year growing season very short
SOILS shallow just above permafrost boggy in
summer very slow decomposition - mats of peat
that transfer little nitrogen to soil
DISTURBANCE winter, freez-thaw cycles, storms,
exposure NUTRIENTS and CYCLING soils nutrient
poor and shallow
93
peeling back the soil and vegetation to the top
of the permafrost
94
  • III. Grasslands
  • A. Shrub Forest - Savannah
  • B. Temperate Grassland (Prairie)
  • C. Arctic Tundra
  • 1. Abiotic
  • 2. Biota
  • No trees - above treeline.

95
III. Grasslands A. Shrub Forest - Savannah B.
Temperate Grassland (Prairie) C. Arctic Tundra 1.
Abiotic 2. Biota No trees - above treeline.
Perennial grasses, mosses, and lichens dominate
the growing season is even too short for annual
herbs to really get going.
96
  • III. Grasslands
  • A. Shrub Forest - Savannah
  • B. Temperate Grassland (Prairie)
  • C. Arctic Tundra
  • 1. Abiotic
  • 2. Biota
  • No trees - above treeline.
  • Perennial grasses, mosses, and lichens dominate
    the growing season is even too short for annual
    herbs to really get going.
  • Mammals tend to remain all year, relying on thick
    fur to weather winters. Some migration into the
    boreal forest does occur.

97
  • III. Grasslands
  • A. Shrub Forest - Savannah
  • B. Temperate Grassland (Prairie)
  • C. Arctic Tundra
  • 1. Abiotic
  • 2. Biota
  • 3. Alpine Tundra

98
  • III. Grasslands
  • A. Shrub Forest - Savannah
  • B. Temperate Grassland (Prairie)
  • C. Arctic Tundra
  • 1. Abiotic
  • 2. Biota
  • 3. Alpine Tundra
  • Elevational treelines vary with latitude, being
    900m at 65N, 2100m at 49N, 3300m at 40N, and
    4200m at 19N.

99
  • III. Grasslands
  • A. Shrub Forest - Savannah
  • B. Temperate Grassland (Prairie)
  • C. Arctic Tundra
  • 1. Abiotic
  • 2. Biota
  • 3. Alpine Tundra
  • Elevational treelines vary with latitude, being
    900m at 65N, 2100m at 49N, 3300m at 40N, and
    4200m at 19N.
  • Soils lack permafrost but are thin and "new".
    Well drained (water runs downslope and does not
    pool) and summer droughts can occur.
  • Dominant plants are perennial grasses and cushion
    plants.

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101
  • III. Grasslands
  • IV. Deserts

102
  • III. Grasslands
  • IV. Deserts
  • 1. Abiotic
  • TEMP Temperatures can vary dramatically,
    depending on time of day, time of year, and
    latitude. Below freezing temperatures are
    possible in high latitude deserts.
  • RAINFALL The common limiting variable is water -
    deserts have less than 25cm/year, on average. In
    warm deserts, the potential evaporation is much
    greater than the precipitation. In Phoenix, AZ,
    potential evapotranspiration is 130 cm a year,
    but rainfall is only 18 cm/year.
  • EVAPOTRANSPIRATIONAL STRESS very high
    desiccating conditions exceed rainfall
  • LIGHT not limiting during growing season
  • SOILS little vegetation cover and slow
    decomposition mean little organic inputs - very
    patchy (under bushes). Otherwise, mineral soil is
    exposed (lithosol). Rainfall does not generate
    enough soil mositure to leach cations capillary
    action may even bring them near to surface and
    form a calcium and magnesium hardpan called
    caliche. These salts exacerbate desiccation.
  • DISTURBANCE desiccation, temperature extremes,
    severe drought, fire
  • NUTRIENTS and CYCLING very poor

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104
  • III. Grasslands
  • IV. Deserts
  • 1. Abiotic
  • 2. Biota

105
  • III. Grasslands
  • IV. Deserts
  • 1. Abiotic
  • 2. Biota
  • Xerophyllic plants adapted to extreme drought
    stress dominate (CAM plants)

106
III. Grasslands IV. Deserts 1. Abiotic 2.
Biota CAM plants (cacti). In deserts where it's
REALLY dry, you can't even have your stomates
open AT ALL during the day... as son as the sun
comes up, it's hot. So, CAM plants keep their
stomates closed in the day, and they only use CO2
stored from the previous evening.
NIGHT - Stomates open, CO2 absorbed and ficed
into a C4 molecule
6(CO2)
6(C6)
6(C5)
C4
C6 (Glucose)
C3
5(C6)
107
III. Grasslands IV. Deserts 1. Abiotic 2.
Biota NIGHT - Stomates open, CO2 absorbed and
fixed into a C4 molecule DAY Stomates closed, C4
is used and CO2 is released and Glucose is
made....this can only be done in the daylight
when ATP ans NADP are made with the light
reaction.
6(CO2)
6(C6)
6(C5)
C4
C6 (Glucose)
C3
C3
5(C6)
108
  • III. Grasslands
  • IV. Deserts
  • 1. Abiotic
  • 2. Biota
  • Xerophyllic plants adapted to extreme drought
    stress dominate (CAM plants)
  • strong diurnal patterns in animal and plant
    activity (CAM)

109
  • III. Grasslands
  • IV. Deserts
  • 1. Abiotic
  • 2. Biota
  • Xerophyllic plants adapted to extreme drought
    stress dominate (CAM plants)
  • strong diurnal patterns in animal and plant
    activity (CAM)
  • Plant density tightly linked to water
    availability.

110
  • III. Grasslands
  • IV. Deserts
  • V. Summary - Terrestrial Biomes
  • NET PRIMARY PRODUCTIVITY (total photosynthesis -
    respiration)

111
  • III. Grasslands
  • IV. Deserts
  • V. Summary - Terrestrial Biomes
  • NET PRIMARY PRODUCTIVITY (total photosynthesis -
    respiration)
  • Take home messages....
  • 1) per unit area, forests are more productive
    than grasslands, which are more productive that
    the open ocean (though REEFS are very
    productive!!)

112
  • III. Grasslands
  • IV. Deserts
  • V. Summary - Terrestrial Biomes
  • NET PRIMARY PRODUCTIVITY (total photosynthesis -
    respiration)
  • Take home messages....
  • 2) multiplying by the area of the biome, we see
    the whole productivity of the biome as a
    percentage of the Earth's productivity...

113
  • III. Grasslands
  • IV. Deserts
  • V. Summary - Terrestrial Biomes
  • NET PRIMARY PRODUCTIVITY (total photosynthesis -
    respiration)
  • Take home messages....
  • 2) Rainforests and the open ocean are responsible
    for over 40 of the planet's productivity.... why
    is this important?

114
  • III. Grasslands
  • IV. Deserts
  • V. Summary - Terrestrial Biomes
  • NET PRIMARY PRODUCTIVITY (total photosynthesis -
    respiration)
  • Take home messages....
  • ... because humans and all other organisms are
    dependent on the NET PRIMARY PRODUCTIVITY... it
    is the base of our food pyramids...

carnivores
HERBIVORES
NET PRIMARY PRODUCTIVITY
115
Study Questions 1.  Why do deciduous trees
dominate where there are cold winters and long
summers? 2. Why do conifers dominate at high
latitudes, high altitudes and in sandy soils? 3. 
Why do grasses dominate some habitats? (climatic
reasons.) 4.  Why are desert soils poor? 5. 
Explain why tropical habitats are more
productive, on average, than temperate habitats.
6. How does C4 photosynthesis work, and why is
it adaptive for plants living in dry
environments? 7. How does CAM photosynthesis work
and why is it adaptive for plants in deserts? 8.
Why are temperate rain forests where they are? 9.
What are the most productive habitats, per unit
area, on the planet? 10. Which biomes contribute
the most to the Earths total NPP? 11. What is
NPP? Why is it an important ecologically to an
ecosystem? 12. Why is the melting of permafrost a
climatic concern?
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