Transcript Terrestrial Biomes

Chapter 3
Communities and Biomes
Section 2, Part 2
Terrestrial Biomes
Latitude
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Position north or south of the equator.
The sun strikes the Earth at different angles at
different latitudes.
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This determines the climate at each latitude.
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Climate includes wind, cloud cover, temperature,
humidity, and precipitation.
Latitude and climate are abiotic factors that
affect what organism can survive in an area.
Tundra
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Circles the polar regions.
Long summer days and short winter days.
Temperatures are rarely above freezing.
Precipitation les than 25 cm per year.
Only the top layer of soil thaws during the
summer.
Under the top layer is a layer of permanently
frozen ground called permafrost.
Tundra
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Although summer days are long, the growing
season is short.
Process of decay is very slow due to cold
temperatures, so nutrients are poor.
Combined with poor nutrient content, the
topsoil is thin, so only shallow-rooted grasses
and small plants, such as dwarf shrubs and
cushion plants, can grow.
Tundra
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Mosquitoes and black flies are common
insects.
Lemmings, weasels, arctic foxes, snowshoe
hares, snowy owls, and hawks are the main
small animals.
Musk oxen, caribou and reindeer migrate into
the area during the summer months.
Taiga
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Also called boreal or northern coniferous
forests.
Located just south of the tundra.
Stretches across much of Canada, Northern
Europe, and Asia.
Forms an almost continuous band of
coniferous trees worldwide.
Taiga
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Warmer and wetter than tundra biomes.
Climatic conditions are harsh with long, severe
winters and short, mild summers.
35 to 100 cm of precipitation per year.
Permafrost is usually absent.
Top soil is acidic and poor in minerals as it
develops slowly from decaying coniferous
needles.
Taiga
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Common trees are larch, fir, hemlock, and
spruce.
When the community is disrupted by fires or
logging, birch, aspen, and other deciduous
trees can colonize the area because the new
soil conditions are with their tolerance range.
Taiga
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Animals common in the Taiga include
weasels, red squirrels, voles, elk, red deer ,
moose, caribou, lynx, snowshoes hares, and a
variety of migratory birds.
Desert
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Arid region with sparse to almost nonexistent
plant life.
Driest biome, usually receiving less than 2 cm
of rain annually.
Rainfall is the biggest limiting factor.
Desert
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Areas receiving higher amounts of rainfall
form shrub communities which may include
drought resistant trees such as mesquite.
Areas receiving less rain have scattered plant
life and large areas of bare land.
Desert
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Desert plants have various adaptations for
living in arid regions.
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Cacti have spines, photosynthetic stems, and waxy
coating to help conserve water and discourage
herbivores.
Some desert plants have leaves that either curl up
or fall off during extreme dry spells.
Many desert plants germinate from seed and grow
to maturity in short time periods after sporadic
rainfall.
Desert
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Many desert animals are small herbivores
which hide during the heat of the day abd
forage on plants at night.
Other animals include kangaroo rats, coyotes,
hawks, owls, roadrunners, snakes, lizards, and
scorpions.
Grasslands
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Also called prairies, steppes, savannas, and
pampas.
In the United States, grasslands are located in
the central and southwestern states.
Grassland
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Receives between 25 and 75 centimeters of
precipitation annually, but usually experience a
dry season, where insufficient water exists to
support forests.
Scattered trees are found throughout with
larger groupings of trees near streams and
other water sources.
Grasslands
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Large communities covered with rich soil.
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Soil has high humus content due to the many
grasses which die off during the winter.
Grass roots survive through the winter,
enlarging every year to form a continuous
underground mat called sod
Grasslands
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Higher biological diversity than deserts.
Other plants include oats, rye, wheat,
sunflowers, and a variety of wildflowers.
Grazing animals include bison, deer, and elk.
Other animals include jack rabbits, prairie
dogs, foxes, and ferrets.
Temperate Forests
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Also called deciduous forests.
Receive 70 to 150 cm of rain annually.
Temperatures from below freezing in the
winter to more than 30 degrees Celsius.
Temperate Forests
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Dominated by broad-leaved hardwood trees
that loose their foliage annually, such as
maple, oak, birch, elm, and ash.
Soil has a top layer that is rich in humus and a
deeper layer of clay.
Animals include squirrels, mice, rabbits, deer,
bluejays, salamanders, and bears.
Rain Forests
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Two types:
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Tropical Rain Forest
Temperate Rain Forest
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Found along the Olympic Peninsula in the U.S. and in
various parts of South America, New Zealand, and
Australia.
Temperatures from 9 to 12 degrees Celsius.
Both types have extensive amounts of moisture
supplied by rainfall or coastal clouds and fogs.
Also have the highest diversity of organisms.
Tropical Rain Forest
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Warm temperatures, wet weather, and lush
plant growth.
Near the equator.
Average temperature is 25 degrees Celsius.
Receive 200 to 600 cm of rain annually.
Animals include sloths, parrots, monkeys,
macaws, frogs, and chameleons
Tropical Rain Forest
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Hypothesis for abundant biodiversity:
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Because they are located near the equator, tropical
rain forests were not covered by ice during the last
ice age and thus have had more time to evolve.
Tropical rain forests have year-round growing
conditions which create a greater food supply
which in turn can support a greater number of
organisms.
Tropical rain forests provide numerous habitats
and niches for diverse organisms.
Tropical Rain Forest
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Tropical rain forests have a large number of niches because of
vertical layering, in which each layer, or story, have differences
which make them suitable for different animals.
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3 main stories:
 Canopy is 25 to 45 meters high and serves as a living roof.
 The understory is still, humid, and dark and has inhabitants
such as ferns, shrubs, insects, frogs, and snakes.
 The ground layer is the moist forest floor where organic
material decays quickly and animals such as the jaguar roam.
Tropical Rain Forest
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Very few nutrients are held in the soil of rain
forests, but instead are quickly recycled
through complex food webs.
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Hot humid climate allows ants, termites, fungi,
bacteria, and other decomposers to break down
dead plants and animals rapidly. Plants must
absorb these nutrients quickly, before they are
washed away by rain.