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Mentor Session 5
Back to Biomes – Then and Now
This week, we will set aside the Antarctica Ice Core Data and turn back to your Biome. In this
exercise, you will trace back how your biome has changed through time. Next Thursday, you
will present this information as a “weather report” from a specific time.
1. Select one region in your biome. For example if you have Grasslands: Savanna, pick one
location, like South America Pampas OR Asian Steppes OR African Savanna, not all
three.
2. Open http://scotese.com/ and explore this website. Pay especial attention to Earth
History and Climate History pages.
3. Locate your biome, and follow that region through time. Starting with your current
temperature and precipitation, track back and record the information available for each
map. You don’t have to find the average temperature and precipitation, instead describe
them in general terms (e.g. cool and arid).
4. After recording the temperature and precipitation, determine which biome best fits those
conditions. If you can only narrow down the past biome to two possibilities, please
record both.
5. When you have completed your region through time, pick a single time period (it can be
any of the 26 maps). Prepare a weather report for your location from that time period.
6. You will present your weather report on February 19, 2009. Be sure to include the
following:
a. Your current biome
b. The location you selected
c. The time you selected
d. A weather report (use what you know about climate and biome. For example,
during the winter, our temperature is generally in the 40s during the day. If you
look at the daily weather, it fluctuates within a range of 20s to 60s (or above on
rare occasion). Base your weather report on a general day for the climate of your
region. Remember, if you are in the Southern Hemisphere, it will be summer.
You can report extreme weather (summer desert and what are the maximum
temperatures from today? Don’t exceed those!
e. If you would like to prepare a weather map on a PowerPoint slide to simulate
what the weather newscasters present, please send it to me by Tuesday the 17th. I
will verify that I can open the file, and I will post it on our class website. Check
your email on Wednesday to make sure that I haven’t sent you notice that I
couldn’t open the file. Be sure to credit where you found the map. Without that
citation, I can’t post it.
f. This is a chance for those of you with a strong creative background to outshine us
nerdy science types! Have fun and get creative weather boys and weather girls!
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The world's biomes
Background material retrieved on January 9, 2009 from, pictures retrieved on February 9, 2009:
http://www.ucmp.berkeley.edu/exhibits/biomes/index.php
http://www.myclimatechange.net/UserImage/3/ArroundTheWorld/CoralReef1.jpg
http://www.41south-aquaculture.com/images/wetland.jpg
http://www.highdesertbulldogges.com/100_0008.JPG
Biomes are defined as "the world's major communities, classified according to the predominant
vegetation and characterized by adaptations of organisms to that particular environment"
(Campbell 1996). The importance of biomes cannot be overestimated. Biomes have changed and
moved many times during the history of life on Earth. More recently, human activities have
drastically altered these communities.
Freshwater
Marine
Desert
Forest
Grassland
Tundra
Freshwater
Freshwater is defined as having a low salt concentration —
usually less than 1%. Plants and animals in freshwater regions are
adjusted to the low salt content and would not be able to survive in
areas of high salt concentration (i.e., ocean). There are different
types of freshwater regions:
 Ponds and lakes
 Streams and rivers
 Wetlands
Marine Water Biomes
Marine regions cover about three-fourths of the Earth's
surface and include oceans, coral reefs, and estuaries. Marine
algae supply much of the world's oxygen supply and take in
a huge amount of atmospheric carbon dioxide. The
evaporation of the seawater provides rainwater for the land.
 Oceans
 Coral reefs
 Estuaries
Wetland Tasmania
Desert Biomes
Coral reef in the Indo-Pacific Ocean
Deserts cover about one fifth of the Earth's surface and occur
where rainfall is less than 50 cm/year. Although most deserts, such as the Sahara of North Africa
and the deserts of the southwestern U.S., Mexico, and Australia, occur at low latitudes, another
kind of desert, cold deserts, occur in the basin and range area of Utah and Nevada and in parts of
western Asia. Most deserts have a considerable amount of specialized vegetation, as well as
specialized vertebrate and invertebrate animals. Soils often have abundant nutrients because they
need only water to become very productive and have little or no organic matter. Disturbances are
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common in the form of occasional fires or cold weather, and sudden, infrequent, but intense rains
that cause flooding.
There are relatively few large mammals in deserts because most are not capable of storing
sufficient water and withstanding the heat. Deserts often provide little shelter from the sun for
large animals. The dominant animals of
warm deserts are nonmammalian
vertebrates, such as reptiles. Mammals are
usually small, like the kangaroo mice of
North American deserts.
Desert biomes can be classified according to
several characteristics.
There are four major types of deserts:
 Hot and dry
 Semiarid
 Coastal
 Cold
Semiarid Desert western Colorado
Forest Biomes
About 420 million years ago, during the Silurian
Period, ancient plants and arthropods began to
occupy the land. Over the millions of years that
followed, these land colonizers developed and
adapted to their new habitat. The first forests
were dominated by giant horsetails, club
mosses, and ferns that stood up to 40 feet tall.
Life on Earth continued to evolve, and in the
late Paleozoic, gymnosperms appeared. By the
Triassic Period (245-208 mya), gymnosperms
dominated the Earth's forests. In the Cretaceous A Wisconsin forest.
Period (144-65m mya), the first flowering plants (angiosperms) appeared. They evolved together
with insects, birds, and mammals and radiated rapidly, dominating the landscape by the end of
the Period. The landscape changed again during the Pleistocene Ice Ages — the surface of the
planet that had been dominated by tropical forests for millions of years changed, and temperate
forests spread in the Northern Hemisphere.
Today, forests occupy approximately one-third of Earth's land area, account for over two-thirds
of the leaf area of land plants, and contain about 70% of carbon present in living things. They
have been held in reverence in folklore and worshipped in ancient religions. However, forests are
becoming major casualties of civilization as human populations have increased over the past
several thousand years, bringing deforestation, pollution, and industrial usage problems to this
important biome.
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Present-day forest biomes, biological communities that are dominated by trees and other woody
vegetation (Spurr and Barnes 1980), can be classified according to numerous characteristics,
with seasonality being the most widely used. Distinct forest types also occur within each of these
broad groups.
There are three major types of forests, classed according to latitude:
 Tropical
 Temperate
 Boreal forests (taiga)
Grassland Biomes
Grasslands are characterized as lands dominated
by grasses rather than large shrubs or trees. In the
Miocene and Pliocene Epochs, which spanned a
period of about 25 million years, mountains rose
in western North America and created a
continental climate favorable to grasslands.
Ancient forests declined and grasslands became
widespread. Following the Pleistocene Ice Ages,
grasslands expanded in range as hotter and drier
climates prevailed worldwide. There are two main
divisions of grasslands:
A grassland west of Coalinga, California.
 Tropical grasslands or savannas
 Temperate grasslands
 Savanna
Tundra Biome
Tundra is the coldest of all the biomes. Tundra comes
from the Finnish word tunturi, meaning treeless plain. It
is noted for its frost-molded landscapes, extremely low
temperatures, little precipitation, poor nutrients, and short
growing seasons. Dead organic material functions as a
nutrient pool. The two major nutrients are nitrogen and
phosphorus. Nitrogen is created by biological fixation,
and phosphorus is created by precipitation.
Characteristics of tundra include:
1. Extremely cold climate
2. Low biotic diversity
Tundra along the Colville River, Alaska.
3. Simple vegetation structure
4. Limitation of drainage
5. Short season of growth and reproduction
6. Energy and nutrients in the form of dead organic material
7. Large population oscillations
Tundra is separated into two types:
 Arctic tundra
 Alpine tundra
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Biomes Through Time
Name _________________________________________________________________________
What location are you tracking within your biome? ____________________________________
Time
Temperature
Precipitation
Biome
Today
Miocene Climate
Oligocene Climate
Late Eocene Climate
Early Eocene Climate
Paleocene Climate
Late Cretaceous Climate
Early Cretaceous Climate
Late Jurassic Climate
Early Jurassic Climate
Late Triassic Climate
Middle Triassic Climate
Early Triassic Climate
Late Permian Climate
Early Permian Climate
Latest Carboniferous Climate
Late Carboniferous Climate
Early Late Carboniferous
Early Carboniferous Climate
Late Devonian Climate
Middle Devonian Climate
Early Devonian Climate
Silurian Climate
Middle & Late Ordovician
Early Ordovician Climate
Middle and Upper Cambrian
Early Cambrian Climate
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