Transcript Chapter 7 powerpoint

Climate & Terrestrial
Biodiversity
Ch. 7
What is Climate?
◊ Weather - short term; today
◊ Climate - general atmospheric or
weather conditions over time
Climate is what we expect;
weather is what we get.
Climate varies over the
surface of the earth
◊ 2 main factors:
• Wind - air circulation
• Ocean currents
◊ Move warm & cold
moisture from one
place to another,
but unevenly
Focus on AIR
◊ Air circulates
warmth &
moisture
from the
tropics to
other places
Focus on AIR
3 forces responsible:
1. Tilt of the earth - Earth is heated
unevenly
Focus on AIR
3 forces responsible
2. Rotation of the Earth on its axis
◊
equator spins faster than poles
◊
Warm air rising over equator goes N
or S then deflected E or W
◊
creates “prevailing winds” - major
surface winds that blow almost
continuously
https://www.youtube.com/watch
?v=rcquRMaVSKU
https://www.youtube.com/watch?v=rcquRMaVSKU
Focus on AIR
3 forces responsible
3. The water cycle
◊
heat from the sun
evaporates ocean water
and transfers it to air
◊
this creates convection
cells that circulate heat,
air, and moisture
Focus on OCEAN CURRENTS
◊ Prevailing winds blow over ocean &
move surface water --> currents
Focus on OCEAN CURRENTS
◊ Currents move warm water to other
places
• Changes vegetation & climate of the area,
especially near the coastline
Focus on OCEAN CURRENTS
◊ Continents and wind currents shape
path of ocean currents
Focus on OCEAN CURRENTS
◊ Currents go clockwise in Northern
Hemisphere
◊ Currents go counterclockwise in
Southern Hemisphere
Focus on OCEAN CURRENTS
◊ Also vertical mixing of water
• Cold water sinks - more dense, saltier
• Warm water rises - less dense, less salty
OCEAN CURRENTS + AIR
CURRENTS 4EVER
◊ Ocean currents
affected by wind
◊ Heat from ocean
affects air
circulation patterns
For Example
◊ El Niño Southern Oscillation
(ENSO)
◊ Changes global weather
over 2/3 of the planet due
to a relatively small change
in wind speed
So…
◊ Air circulation + winds
+ ocean currents +
continents in the way =
6 giant convection cells
that shape climate
◊ (3 in north, 3 in south)
◊ Warm wet air rises
◊ Cool dry air sinks
The Atmosphere
◊ Greenhouse gases warm the Earth
• H2O, CO2, CH4, N2O
How they work
◊ Light from sun passes
through atmosphere
◊ Surface absorbs heat
◊ Heat radiates back up
◊ Some escapes to space
◊ Some absorbed by
greenhouse gases - its
good! :)
Climate Change
◊ LOTS and LOTS of evidence
supports the hypothesis
that humans are
contributing excess
greenhouse gases to the
atmosphere - altering
earth’s climate
◊ 90-99% sure of this
◊ Why not 100%
◊ Precautionary Principle
(global warming)
Earth’s Surface Features also
affect climate
◊ Rain shadow effect
• Windward side wet
• Leeward side dry
All of this creates BIOMES
High Mountains
Polar Ice
Arctic Tundra
Temperate
Grassland
Tropical
grassland
(savanna)
Chaparral
Temperate
Coniferous forest
Temperate
deciduous forest
Tropical rainforest
Tropical dry
forest
Tropical Desert
Temperate rain
forest
Temperate desert
Cold desert
Taiga
Tropical and
subtropical coniferous
forest
Pond
Inland wetlands
(swamps, marshes,
prarie potholes)
Mangrove forest
Riparian (rivers
and surrounding
area)
All of this creates BIOMES
High Mountains
Polar Ice
Arctic Tundra
Temperate
Grassland
Tropical
grassland
(savanna)
Chaparral
Temperate
Coniferous forest
Temperate
deciduous forest
Tropical rainforest
Tropical dry
forest
Tropical Desert
Temperate rain
forest
Temperate desert
Cold desert
Taiga
Tropical and
subtropical coniferous
forest
Pond
Littoral, intertidal
zone
Mangrove forest
Kelp forest
Coral reef
Neritic zone
(coastal waters)
Continental shelf
Pelagic zone (open
sea)
Benthic zone
(bottom of lakes
and oceans)
Hydrothermal vents
Cold seeps
Estuaries
Riparian (rivers and
surrounding area)
Inland wetlands
(swamps,
marshes, prarie
potholes)
Climate Helps Determine
Where Organisms Can Live
◊ Major biomes
• Large land regions with certain types of
climate and dominant plant life
◊ Not uniform
◊ Mosaic of patches
◊ Change with latitude and elevation
Climate Helps Determine Where
Organisms Can Live (cont’d.)
Hot
Wet
Dry
3 types of Desert, Grasslands
& Forests …know these!
◊ Tropical
◊ Temperate
◊ Cold
•Desert – annual precipitation low
and often scattered through
the year
•Grasslands occur in:
•Interior continents too moist for
deserts and too dry for forests
•Forests – lands dominated by
trees
Humans Have Disturbed Much of
the Earth’s Land
◊ About 60% of the world’s major
terrestrial ecosystems are being
degraded
◊ The human ecological footprint is
spreading across the globe
Size and Locations of Biomes
Can Change
◊ Biomes are not fixed
• They change as the climate changes
◊ Human activities are likely to affect biome placement
in the future
Three Big Ideas
◊ Differences in climate:
• Based on long-term differences in average temperature and
precipitation
• Largely determine the types and locations of the earth’s
deserts, grasslands, and forests
◊ The earth’s terrestrial systems provide important ecological and
economic services
◊ Human activities are degrading and disrupting many of the
ecological and economic services provided by the earth’s
terrestrial ecosystems
Tying It All Together: A Temperate Deciduous
Forest and Sustainability
◊ Climate plays a key role in determining
the nature of terrestrial ecosystems
◊ The earth’s dynamic climate system
helps distribute heat from solar energy
and recycle the earth’s nutrients
◊ In nature, everything is connected