Geoscience Reference
In-Depth Information
S U M M A R Y O F K E Y C O N C E P T S
1. Biogeography examines the geographical distributions
of organisms, ecosystems, and the environmental
contexts in which they occur.
savanna occurs in the tropical ecotone where the ITCZ
dominates in the summer (bringing the wet season) and
the STH dominates in winter (bringing the dry season).
Midlatitude grasslands occur deep within continents or
within rain shadows.
2. The photosynthetic, respiratory, and decomposition
cycles explain how biomass is produced and consumed
through the interaction of solar energy, carbon dioxide,
water, and oxygen in plants, animals, and soil.
6. Two major desert biomes are recognized in the world:
(1) hot and dry desert, and (2) semi-arid and cold desert
biome. The hot and dry desert occurs in the higher tropi-
cal latitudes, dominated by the STH Pressure System.
The semi-arid and cold desert biome occurs deep within
continents and rain shadows within the midlatitudes.
3. A biome is a definable geographic region that is classi-
fied and mapped according to the predominant vegeta-
tion and the adaptations of organisms to that particular
environment. Twelve major biomes are recognized on
Earth.
7. The tundra biome occurs at very high latitudes and el-
evations where environmental conditions are too harsh
for trees to grow. The plants here consist of low-growing
woody shrubs, lichens, and mosses.
4. Six major forest biomes in the world occur in places
where average annual precipitation is high. They also oc-
cur in places that have moderate amounts of precipita-
tion and average temperatures that are sufficiently cool
to maintain a good water balance.
8. The human impact on the distribution and character
of natural vegetation around the planet has been dra-
matic, including deforestation, extensive agriculture, and
overgrazing.
5. The two major grassland biomes in the world are (1) trop-
ical savanna and (2) midlatitude grassland. The tropical
C H E C K Y O U R U N D E R S T A N D I N G
1. Define the concept of ecosystems and the various
components within them.
8. Describe the change in the character of grasses in the
Great Plains from the eastern part of the grassland to
the west. Why does this difference exist?
2. Explain the process of photosynthesis and why it is
important to life on Earth.
9. Where would the warmest/driest slopes be in the
Southern Hemisphere: on the north- or south-facing
slopes?
3. Why is biomass higher in tropical regions than in desert
regions?
10. Where is overgrazing likely to have the biggest impact:
in the Great Plains or in the eastern United States?
Why does this difference exist?
4. Describe the concept of global biomes and the factors
that influence them.
5. Why is the floor of the tropical rainforest biome
considered to be “open”?
11. Why is there likely to be a denser forest on the wind-
ward side of a mountain range than on the leeward
side?
6. Many of the trees in the tropical deciduous forest bi-
ome can be found in the tropical rainforest biome.
Nevertheless, the trees in the rainforest are evergreen,
whereas they drop their leaves in the tropical deciduous
forest biome. Why does this difference exist?
12. Explain the concept of plant succession.
13. Tundra is found in the very low latitudes of South
America, even though this region is commonly thought
to be “tropical.” Why?
7. The ITCZ and STH Pressure System are very closely
associated with the tropical savanna biome. What is this
relationship?
14. Discuss the rates and geography of deforestation on
Earth.
 
 
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