ch 3 ecosystems

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