ch 3 ecosystems
TRANSCRIPT
CH 3 ECOSYSTEMS
Tropical Rainforests Are Disappearing
Found near the equator 6% land surface 50% world’s known terrestrial plant and
animal species
TRF Disappearing ≥50% destroyed or disturbed by humans
Cutting trees Growing crops Grazing cattle Building settlements
Tropical Rainforests Are Disappearing
Consequences of disappearing tropical rainforests:1. Decreased biodiversity as species become
extinct2. Accelerated global warming (why??)fewer trees to remove carbon dioxide from the atmosphere3. Changes regional weather patterns: can lead
to increase in tropical grasslands
Fig. 3-1, p. 39
What Keeps Us and Other Organisms Alive?
The four major components of the earth’s life-support system are:
1. Atmosphere (air) 2. Hydrosphere (water)
3. Geosphere (rock, soil, sediment) 4. Biosphere (living things).
Earth’s Four Major Life-Support Systems
1. Atmosphere – Air Stratosphere – ozone layer – blocks sun’s
harmful UV rays Troposphere – consist of ……… 78% Nitrogen 21% Oxygen 1%greenhouse gasses –
(water, carbon dioxide, and methane)
Earth’s Four Major Life-Support Systems
Hydrosphere – All of the water found near or on earth’s surface.
Ex – liquid, polar ice, icebergs, permafrost, and water vapor
Earth’s Four Major Life-Support Systems
Geosphere – Rock / earth, includes the earth’s core.
Earth’s Four Major Life-Support Systems
Biosphere – parts of the other 3 spheres where life is found.
Goal of Ecology is to understand the interactions that occur between these
Fig. 3-2, p. 41
RockCrust
Atmosphere
Vegetationand animals
Biosphere
Mantle
Lithosphere
Soil
Geosphere(crust, mantle, core)
Mantle
Core
Crust(soil and rock)
Biosphere(living organisms)
Atmosphere(air)
Hydrosphere(water)
Three Factors Sustain Life on Earth
1. One-way flow of high-quality energy from the sun
2. Cycling of matter or nutrients through parts of the biosphere
3. Gravity
Solarradiation
Radiated byatmosphereas heat
Reflected byatmosphere
Mostabsorbedby ozone
Absorbedby the earth
Greenhouseeffect
Visiblelight
UV radiation
Heat radiatedby the earthHeat
Troposphere
Lower Stratosphere(ozone layer)
Fig. 3-3, p. 41