Biology
Chapter 4-1
Ecosystems and Communities
4-1 The Role of Climate
A. Weather is the daily conditions of temperature and
precipitation in a particular place.
B. Climate is the average, year after year conditions of
temperature and precipitation in a particular region.
Many factors are involved in determining “climate”
1.
a.
Atmosphere trapping heat
Sunlight
Some heat
escapes
into space
Greenhouse
gases trap
some heat
Atmosphere
Earth’s surface
b.
Latitude
900 N latitude
400 N latitude
00 latitude
400 S latitude
900 S latitude
c.
Transport of heat by wind and ocean currents
d.
Precipitation
e.
Shape of landmasses
f.
Elevation of landmasses
C.
Greenhouse Effect
1. a warming of
the atmosphere
because of heat
trapped by gases.
Sunlight
Some heat
escapes
into space
Greenhouse
gases trap
some heat
Atmosphere
Earth’s surface
2. greenhouse
gases—gases that trap
heat energy of the
sunlight inside the
earth’s atmosphere.
a.
b.
c.
Carbon dioxide,
Methane,
Water vapor.
3.
a balance of heat gained and heat lost is important.
a. If the greenhouse gases were not present the earth would
be 30 oC (~85oF) cooler than it is today. (~30 below zero F)
b. However, if we produce too much of the greenhouse
gases there is a danger of global warming which could
destroy life as we know it.
D.
Earth has 3 main climatic zones:
1. these zones are caused by differences in latitude and
the angle of heating caused by the sun’s rays.
a.
Polar
1)
Cold areas
2)
Sun strikes earth at low angle
3)
Located between 66.5o and 90o north and south latitudes
90°N North Pole
Low angle
Arctic circle
66.5°N
Sunlight
Most direct sunlight
Sunlight
Arctic circle
Low angle
66.5°S
90°S South Pole
b.
Temperate
1)
Intermediate zone between polar and tropical zones
2)
Changing seasons, warm to cool seasons
3) Located between 66.5o and 23.5o north and south
latitudes
Low angle sunlight
Arctic circle
Sunlight
66.5°N
Tropic of Cancer
23.5°N
Tropic of Capricorn
23.5°S
Most direct sunlight
Sunlight
Arctic circle
Low angle sunlight
66.5°S
c. Tropical
1) Warm area
2)
3)
Sun strikes nearly or directly on the surface.
Located between 23.5o north and 23.5o south.
Low angle sunlight
Sunlight
Tropic of Cancer
23.5°N
Tropic of Capricorn
23.5°S
Most direct sunlight
Sunlight
Low angle sunlight
E.
Heat is transported by wind and ocean currents.
1. because of unequal heating of the earth’s surface, warm
air rises and cold air sinks. Air moving between rising and
sinking air is called wind.
2. Global weather patterns develop based on these wind
patterns.
3. The same thing happens in the oceans with water.
Warm water rises and cold water sinks. As water moves
between warm areas and cold areas currents are produced.
4. wind and ocean currents spread heat over the planet. So
the earth is rather uniformly within a suitable temperature
range. If the earth didn’t have these currents, there would be
great extremes in temperature.