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Chapter 29Chapter 29
The Earth’sThe Earth’sDiverseDiverse
EcosystemsEcosystems
Chapter 29 2
Factors That Influence ClimateFactors That Influence Climate
The distribution of life on Earth is dramatically The distribution of life on Earth is dramatically affected by weather and climateaffected by weather and climate
• Weather:Weather: short-term fluctuations in short-term fluctuations in temperature, humidity, cloud cover, wind, temperature, humidity, cloud cover, wind, and precipitation; affects individual and precipitation; affects individual organismsorganisms
• Climate:Climate: long-term patterns of weather; limits long-term patterns of weather; limits distribution of speciesdistribution of species
Chapter 29 3
The SunThe Sun
Solar energy drives both weather and climateSolar energy drives both weather and climate• It drives the wind, ocean currents, and global It drives the wind, ocean currents, and global
water cycle water cycle Solar energy reaching outer atmosphere Solar energy reaching outer atmosphere
includesincludes• Ultraviolet (UV): short wavelengths; high Ultraviolet (UV): short wavelengths; high
energy energy • Visible light: intermediate wavelengths; used Visible light: intermediate wavelengths; used
for photosynthesis, vision for photosynthesis, vision • Infrared (IR): long wavelengths; low energy; Infrared (IR): long wavelengths; low energy;
radiant heatradiant heat
Chapter 29 4
The SunThe Sun
Before solar energy reaches Earth's surface it Before solar energy reaches Earth's surface it is modified by the atmosphereis modified by the atmosphere
• Ozone layerOzone layer: stratosphere (middle layer) rich : stratosphere (middle layer) rich in ozone (Oin ozone (O33) absorbs much of sun's UV, ) absorbs much of sun's UV, converting it to heatconverting it to heat
• Dust, water vapor, and clouds scatter light, Dust, water vapor, and clouds scatter light, reflecting some back into space reflecting some back into space
• Greenhouse gasesGreenhouse gases selectively absorb IR selectively absorb IR energy and trap heat in atmosphereenergy and trap heat in atmosphere
Chapter 29 5
Satellite Image of Satellite Image of Antarctic Ozone HoleAntarctic Ozone Hole
AntarcticaAntarcticaAntarcticaAntarctica
South AmericaSouth AmericaSouth AmericaSouth America
The “hole”The “hole”The “hole”The “hole”
Chapter 29 6
Physical Factors that Affect ClimatePhysical Factors that Affect Climate
IncludeInclude• Earth’s curvature and tiltEarth’s curvature and tilt• Air currentsAir currents• Ocean currentsOcean currents• Continent and mountain position Continent and mountain position
Chapter 29 7
Curvature and TiltCurvature and Tilt
The amount of sunlight that strikes a given The amount of sunlight that strikes a given area of Earth’s surface has a major effect area of Earth’s surface has a major effect on average yearly temperatureson average yearly temperatures
Chapter 29 8
Earth’s Curvature, TiltEarth’s Curvature, TiltMake Seasons & ClimateMake Seasons & Climate
Short days;Long nights;
Winter
Long days;Short nights;
Summer
Reversed whenReversed whenon other sideon other side
of Sunof Sun
Chapter 29 9
Air CurrentsAir Currentsand Climatic Regionsand Climatic Regions
Air rises & cools near Air rises & cools near equatorequator
• Causes much rainCauses much rain• Tropical rain forestsTropical rain forests
Rising air travels N & S Rising air travels N & S from equatorfrom equator
• Descends @ 30° N & SDescends @ 30° N & S• Very dry air causes Very dry air causes
deserts theredeserts there
Repeated again at 60° Repeated again at 60° & 90° (poles)& 90° (poles)
Chapter 29 10
Air CurrentsAir Currentsand Climatic Regionsand Climatic Regions
Saharan & Arabian deserts Saharan & Arabian deserts are @ 30° Nare @ 30° N
South African DesertSouth African Desertis @ 30° Sis @ 30° S
Congo rain forest is @ 0°Congo rain forest is @ 0°
Chapter 29 11
Ocean CurrentsOcean Currents
Water heats and cools more slowly than Water heats and cools more slowly than land or airland or air
• Reduces temperature extremes in coastal Reduces temperature extremes in coastal areas areas
Ocean currents are driven by winds and by Ocean currents are driven by winds and by direct heating of water by the sun direct heating of water by the sun
Chapter 29 12
Ocean CurrentsOcean Currents
Continents and Earth's rotation produce Continents and Earth's rotation produce circular circular gyresgyres
• Gyres rotate clockwise in Northern Gyres rotate clockwise in Northern Hemisphere; opposite in SouthHemisphere; opposite in South
• Gulf Stream moves warm water from Gulf Stream moves warm water from Caribbean up eastern shore of North Caribbean up eastern shore of North America and over to Western Europe; America and over to Western Europe; warmer, moister climate as resultwarmer, moister climate as result
Chapter 29 13
Ocean CirculationOcean CirculationPatterns: GyresPatterns: Gyres
N. PacificGyre
S. PacificGyre
N. AtlanticGyre
S. AtlanticGyre
Chapter 29 14
Continents and MountainsContinents and Mountains
Regular bands of uniform climate would Regular bands of uniform climate would form if not for presence of continents form if not for presence of continents
• Continents heat and cool more quickly than Continents heat and cool more quickly than surrounding oceanssurrounding oceans
• Continents have irregular shapes Continents have irregular shapes • These factors alter flow of wind and water, These factors alter flow of wind and water,
resulting in irregular ecosystem resulting in irregular ecosystem distributiondistribution
Chapter 29 15
Continents and MountainsContinents and Mountains
Variations in elevation within continents Variations in elevation within continents further complicate climate zonesfurther complicate climate zones
• At higher altitudes air is thinner and retains At higher altitudes air is thinner and retains less heatless heat
• Temperature drops about 3.5 ºF for every Temperature drops about 3.5 ºF for every 1000 feet rise in elevation 1000 feet rise in elevation
Chapter 29 16
Effects of ElevationEffects of Elevationon Temperatureon Temperature
Low
Low
(
( A
ltitu
de)
Alti
tude
)
H
igh
Hig
hLo
wLo
w
(
( Alti
tude
)A
ltitu
de)
Hig
hH
igh
EquatorialEquatorial (Latitude) (Latitude) PolarPolarEquatorialEquatorial (Latitude) (Latitude) PolarPolar
Chapter 29 17
Continents and MountainsContinents and Mountains
Mountains also modify rainfall patterns Mountains also modify rainfall patterns • When moist air is forced over a mountain, it When moist air is forced over a mountain, it
expands and cools expands and cools • Cooler air holds less moisture, thus rain or Cooler air holds less moisture, thus rain or
snow falls on windward sidesnow falls on windward side• As air moves down far side of mountain, it As air moves down far side of mountain, it
warms but stays dry, forming a local dry warms but stays dry, forming a local dry area called a area called a rain shadowrain shadow
Chapter 29 18
Chapter 29 19
The Sierra NevadaThe Sierra NevadaRain ShadowRain Shadow
WestWest EastEast
100100
5050
00
50005000
40004000
30003000
20002000
10001000
00
Average AnnualAverage AnnualPrecipitation (cm)Precipitation (cm)
Altitude (m)Altitude (m)
150150
Chapter 29 20
Conditions Required for LifeConditions Required for Life
Four fundamental resources are required for Four fundamental resources are required for lifelife
• Nutrients from which to construct living Nutrients from which to construct living tissuetissue
• Energy to power that construction Energy to power that construction • Liquid water to serve as medium for Liquid water to serve as medium for
metabolic reactions metabolic reactions • Appropriate temperatures in which to carry Appropriate temperatures in which to carry
out these processes out these processes
Chapter 29 21
How Is Life on Land Distributed?How Is Life on Land Distributed?
Distribution of terrestrial organisms is Distribution of terrestrial organisms is limited primarily by water availability and limited primarily by water availability and temperature temperature
• Water and temperature are unevenly Water and temperature are unevenly distributed in space and timedistributed in space and time
Chapter 29 22
Terrestrial BiomesTerrestrial Biomes
Terrestrial communities are dominated and Terrestrial communities are dominated and defined by their plant lifedefined by their plant life
• Plants are precisely adapted to climate of Plants are precisely adapted to climate of region (they can't escape their conditions)region (they can't escape their conditions)
• Large land areas with similar environmental Large land areas with similar environmental conditions and characteristic plant conditions and characteristic plant communities are called communities are called biomesbiomes
Chapter 29 23
The Distribution of 11 BiomesThe Distribution of 11 Biomes
Chapter 29 24
Hig
hH
igh
(
( T
empe
ratu
re)
Tem
pera
ture
)
Lo
wLo
wH
igh
Hig
h
(
( Tem
pera
ture
)Te
mpe
ratu
re)
Low
Low
DryDry (Rainfall) (Rainfall) WetWetDryDry (Rainfall) (Rainfall) WetWet
Rainfall & Temp.Rainfall & Temp.Affect Biome DistributionAffect Biome Distribution
Chapter 29 25
Tropical Rain ForestTropical Rain Forest
Chapter 29 26
TropicalTropicalRain Forest BiomeRain Forest Biome
Temp 77-86 °F (25-30 °C)Temp 77-86 °F (25-30 °C)Rainfall 100-160 in (25-40 cm)/yRainfall 100-160 in (25-40 cm)/yBiodiversity: 50-67% of all Biodiversity: 50-67% of all Earth’s speciesEarth’s species6% of land area6% of land area
• 40% now gone40% now gone• losing 70 acres/minlosing 70 acres/min• > 25000 species go extinct > 25000 species go extinct
annuallyannuallyDominated by large, broadleaf, Dominated by large, broadleaf, evergreen treesevergreen treesVertically structuredVertically structured
Chapter 29 27
Tropical Deciduous ForestTropical Deciduous ForestFurther from equatorFurther from equatorPronounced wet & dry seasons; deciduous treesPronounced wet & dry seasons; deciduous trees
Chapter 29 28
SavannaSavanna
Chapter 29 29
The African SavannaThe African Savanna
Grasses dominate; Grasses dominate; scattered trees and thorn scattered trees and thorn forestsforests
Short rainy seasonShort rainy season
• <12 in. (30 cm) annually<12 in. (30 cm) annually
• Long, severe droughtsLong, severe droughts
African savanna with many African savanna with many large animalslarge animals
Many species in danger of Many species in danger of extinctionextinction
Chapter 29 30
DesertsDeserts
Chapter 29 31
The Desert BiomeThe Desert Biome
Usually found between 20-Usually found between 20-30° N & S latitude30° N & S latitude
Less than 10 in. (25 cm) Less than 10 in. (25 cm) rain annuallyrain annually
Plants often spaced very Plants often spaced very evenlyevenly
Boom & bust population Boom & bust population growth after raingrowth after rain
Very fragile ecologyVery fragile ecology
Chapter 29 32
ChaparralChaparral
Chapter 29 33
The Chaparral BiomeThe Chaparral Biome
Often in coastal regions Often in coastal regions bordering desertsbordering deserts
Up to 30 in. rain annually, Up to 30 in. rain annually, but all during cool monthsbut all during cool months
Summers hot & drySummers hot & dry
Small trees & large bushesSmall trees & large bushes
Chapter 29 34
GrasslandsGrasslands
Chapter 29 35
GrasslandsGrasslands
10-30 in. (25-75 cm) rain 10-30 in. (25-75 cm) rain annuallyannually
Usually in centers of Usually in centers of continentscontinents
No trees except along No trees except along riversrivers
• Periodic severe Periodic severe droughtsdroughts
• Frequent firesFrequent fires
Most fertile soil in worldMost fertile soil in world
Destroyed by overgrazingDestroyed by overgrazing
Shortgrass PrairieShortgrass PrairieShortgrass PrairieShortgrass Prairie
Sagebrush Desert orSagebrush Desert orShortgrass PrairieShortgrass Prairie
Sagebrush Desert orSagebrush Desert orShortgrass PrairieShortgrass Prairie
Chapter 29 36
Temperate Deciduous ForestsTemperate Deciduous Forests
Chapter 29 37
The Temperate DeciduousThe Temperate DeciduousForest BiomeForest Biome
30-60 in. (75-150 cm) rain 30-60 in. (75-150 cm) rain annually, most during annually, most during summersummer
Mostly deciduous trees, Mostly deciduous trees, bare in winterbare in winter
Leaf litter on soilLeaf litter on soil
High diversity of animalsHigh diversity of animals
Chapter 29 38
Temperate Rain ForestTemperate Rain Forest
Chapter 29 39
The Temperate RainThe Temperate RainForest BiomeForest Biome
Abundant rainAbundant rain
Soil seldom frozenSoil seldom frozen
Usually coastalUsually coastal
Chapter 29 40
TaigaTaiga
Chapter 29 41
The Taiga (or NorthernThe Taiga (or NorthernConiferous Forest) Biome Coniferous Forest) Biome
Northern coniferous Northern coniferous forestsforests
Northern Canada and Northern Canada and EurasiaEurasia
Winters long and coldWinters long and cold
Evergreen coniferous Evergreen coniferous trees with needle-like trees with needle-like leavesleaves
Plant & animal diversity Plant & animal diversity lowlow
Chapter 29 42
TundraTundra
Chapter 29 43
The Tundra BiomeThe Tundra Biome
Treeless region bordering Pacific OceanTreeless region bordering Pacific Ocean< 10 in. rain annually< 10 in. rain annuallyPermanently frozen soil (permafrost)Permanently frozen soil (permafrost)Very fragile, scars last for centuriesVery fragile, scars last for centuries
Chapter 29 44
Survey of Aquatic EcosystemsSurvey of Aquatic Ecosystems
71% of Earth's surface71% of Earth's surface
Water moderates temperatureWater moderates temperature
Energy (top) and nutrients (bottom) affect lifeEnergy (top) and nutrients (bottom) affect life
Chapter 29 45
Freshwater EcosystemsFreshwater Ecosystems
Less than 1% of Earth's surfaceLess than 1% of Earth's surface• Rivers, streams, ponds, lakes, marshesRivers, streams, ponds, lakes, marshes• Life zones:Life zones:
– based on access to lights/nutrientsbased on access to lights/nutrients– vary by depth/clarity of watervary by depth/clarity of water
Human impactHuman impact• EutrophicationEutrophication
– Accelerated via addition of nutrient wastesAccelerated via addition of nutrient wastes– Results in oxygen depletionResults in oxygen depletion
• Acid rainAcid rain– Creates appearance of oligotrophyCreates appearance of oligotrophy– Almost sterileAlmost sterile
Chapter 29 46
Lake Life ZonesLake Life ZonesLittoralLittoral
• ShallowShallow• Well litWell lit• Communities most Communities most
diversediverseLimneticLimnetic
• Too deep for rootsToo deep for roots• Well lit, so supports Well lit, so supports
phytoplanktonphytoplanktonProfundalProfundal
• Too deep for Too deep for photosynthesisphotosynthesis
• DecomposersDecomposers
Littoral ZoneLittoral Zone
Limnetic ZoneLimnetic Zone
Profundal ZoneProfundal Zone
Chapter 29 47
Marine ecosystemsMarine ecosystems
70% of Earth's surface70% of Earth's surfaceBays, wetlands (salt marshes, estuaries), open Bays, wetlands (salt marshes, estuaries), open
oceanoceanCoastal marine ecosystemsCoastal marine ecosystems
• Support the most abundant life and Support the most abundant life and • Commercially important (crabs, shrimp, fish, Commercially important (crabs, shrimp, fish,
recreation, petroleum)recreation, petroleum)
Human impactHuman impact• Wetland destruction equals rain forest destructionWetland destruction equals rain forest destruction• Half of U.S. wetlands have been destroyedHalf of U.S. wetlands have been destroyed
Chapter 29 48
Ocean Life ZonesOcean Life ZonesPhotic zone Photic zone (photosynthesis)(photosynthesis)
• Intertidal; Alternately Intertidal; Alternately coveredcovered
• Near tidal; below low Near tidal; below low tide but shallowtide but shallow
• Pelagic; open ocean to Pelagic; open ocean to 200 ft200 ft
Aphotic zone (no Aphotic zone (no photosynthesis)photosynthesis)
• Below 200 ftBelow 200 ft• Supported by drift from Supported by drift from
photic zonephotic zoneHydrothermal ventsHydrothermal vents
Chapter 29 49
Estuaries: where rivers Estuaries: where rivers meet the oceanmeet the oceanEstuaries: where rivers Estuaries: where rivers meet the oceanmeet the ocean
Kelp beds: in Kelp beds: in photic zonephotic zone
Kelp beds: in Kelp beds: in photic zonephotic zone
Near-ShoreNear-ShoreEcosystemsEcosystems
Chapter 29 50
Coral Reefs:Coral Reefs:Bodies of corals & Bodies of corals & algaealgaeMany fish & Many fish & invertebratesinvertebratesDelicateDelicate
Coral Reefs:Coral Reefs:Bodies of corals & Bodies of corals & algaealgaeMany fish & Many fish & invertebratesinvertebratesDelicateDelicate
Open Ocean:Open Ocean:Most life in photic Most life in photic
zonezoneSwim or floatSwim or float
Open Ocean:Open Ocean:Most life in photic Most life in photic
zonezoneSwim or floatSwim or float
Coral Reefs & Open OceanCoral Reefs & Open Ocean
Chapter 29 51
Hydrothermal Vent CommunitiesHydrothermal Vent Communities
Found where sea floor is spreading (>250 m deep)Found where sea floor is spreading (>250 m deep)
First discovered in 1977First discovered in 1977
Vents spew superheated,Vents spew superheated,nutrient-rich waternutrient-rich water
Chemosynthetic sulfurChemosynthetic sulfurbacteria primary producersbacteria primary producers
• One survives @ 248°FOne survives @ 248°F• Sulfur is oxidized forSulfur is oxidized for
energyenergy• Others eat the bacteria, etc.Others eat the bacteria, etc.
248 new species and 22 new families248 new species and 22 new families
Chapter 29Chapter 29
The EndThe End
