Transcript Chapter 2, Section 2

Chapter 2, Section 2
ECOSYSTEMS
II. Ecosystems
Even in harsh polar regions and arid deserts,
plants and animals grow in response to their
environment.
A. Ecosystems
i. Groups of plants and animals tend to be
interdependent.
1. Shade
2. Support
3. Nourishment
ii. An ecosystem is formed by the interaction of
plant life, animal life, and the physical
environment in which they live.
iii. Various physical conditions affect the survival and
growth of life in an ecosystem.
These factors include:
1. Climate
2. Sunlight
3. Temperature
4. Precipitation
5. Elevation
6. Soil
7. Landforms
iv. Environments with similar conditions tend to
support similar communities of plants and animals.
Environmental Change
• EX. In a forest, the loss of oak trees will endanger
squirrels and other animals that rely on acorns
for food.
• As populations grow, ecosystems change
dramatically.
– Grasslands become farmland.
– Loss of habitat leads to severe decline in animal and
plant populations.
– Some species do thrive because of human changes.
Biomes
• Geographers classify ecosystems by their
natural plant and animal life.
• Biome is used to describe major types of
ecosystems found in various regions of world.
– Ex. DECIDUOUS forest  Likely to have moderate
climate conditions, oak or maple trees and
animals such as deer, squirrels, cardinals and owls.
B. Forest Regions
i. Forest vegetation grows on every continent
except Antarctica.
a. Three most common Forest Regions are:
1. Tropical Rain Forests
2. Mid-Latitude Forests
3. Coniferous Forests
 However others do exist…
Tropical Rain Forests
• Exist in areas near the equator.
• Large amounts of rain fall.
• Largest are in the Amazon and Congo River
basins.
• Tall trees form dense canopy of leaves that
blocks much of the sun from the forest floor.
• Varying conditions in layers lead to different
types of plants and animals.
• Cover only 6% of the earth but contain more
than half of the earth’s plants and animal
species.
Mid-Latitude Forest
• Trees are deciduous, they shed their leaves
during one season, usually autumn.
• Looks vary by season, stark and bare in the
winter and lush and green in the summer.
• Deciduous forests once covered much of
Europe, eastern N. America and Eastern Asia.
• Lands in the middle latitudes have a
temperate climate with adequate rainfall,
warm summers, and cool or cold winters.
Coniferous Forest
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Consists of Pines, spruces, firs.
These trees can survive long, cold winters.
Trees have needles instead of leaves.
Name comes from cones that protect their
seeds.
• Bears and deer live here but smaller animals
have adapted to the harsh conditions.
Other Forest Types
• Mixed Regions – forest regions overlap.
• Coniferous and deciduous grow together in
same areas. Common in Northern U.S.
• Chaparral – includes small evergreen trees
and low brushes.
• Adapted to Mediterranean climate. = Most
precipitation falls during winter and summers
are hot and dry.
C. Grasslands
• Central regions of several continents are
covered by grasslands.
• Grasslands and forests often mix.
• Characteristics of grasslands vary depending
on their latitudes.
– 2 types of Grasslands
1. Tropical Grasslands
2. Temperate Grasslands
Tropical Grasslands
• Tropical grasslands AKA savannas grow in
warm lands near the Equator.
• Scattered trees and plants.
• Animals:
Herbivores – Gazelles and Zebras
Carnivores – Lions and Hyenas
• Three Seasons:
– Wet
– Dry
– Time of naturally occurring wildfires.
Temperate Grasslands
• Prairies
– Temperate grasslands of N. America.
– More rain = taller grass.
– Prairies are now a rare site… Much of grassland region
was plowed under to provide fertile farmland.
Temperate Grassland Continued…
• Steppes
– Cool, dry, temperate grasslands of Northern
Eurasia and Central Asia similar to Great Plains.
– Steppe = comes from Russian word for treeless
plain.
D. Deserts
• Desert regions are not just barren expanses of
sand.
• Many plants and animals adapt to survive with
almost no water.
– Ex. Cactus Plants = store water.
– Saguaro cactus expands like a sponge to absorb water.
– Cactus leaves are prickly needles for protection.
Deserts continued…
• Like plants, animals in the desert are adapted to
extreme temperatures and scarcity of water.
– Many do not need to drink at all.
– Get moisture from seeds, plants or animals they eat.
– Camels can survive for days without food or water by
drawing on the fat stored in their humps.
 Alpine Tundra
E. Tundras
 Exist in high mountains.
 No trees grow at these high elevations.
 Small plants and wildflowers grow in sheltered spots.
 Tiny, brightly colored plants called lichens make
patterns on the rocks.
Tundra continued…
• Arctic Tundra
– Cold temps. and short growing seasons.
– No sunlight for most of winter.
– Treeless, covered with grasses, mosses, lichens
and some flowering plants.
– Parts of the tundra, a layer of soil just below the
surface (Permafrost) stays permanently frozen.