Transcript Ch 21 and 22 Powerpoint

CH 21 AND 22
Turk
NIHS
Chapter 21
Section 1 Terrestrial Biomes
The Major Biomes
■ The major types of terrestrial ecosystems, known as biomes,
are tundra, tropical forest, temperate forest, taiga, temperate
grassland, savanna, chaparral, and desert.
Chapter 21
Section 1 Terrestrial Biomes
Tundra
■ Tundra is a cold biome characterized by permafrost
under the surface of the ground.
Chapter 21
Section 1 Terrestrial Biomes
Forests
■ Tropical Forests
– Tropical forests receive abundant rainfall and have stable
temperatures.
– They have a greater species richness than any other biome.
Chapter 21
Section 1 Terrestrial Biomes
Forests, continued
■ Temperate Forests
– Temperate forests have coniferous
trees, which bear seeds in cones, or
deciduous trees, which shed their
leaves each year.
■ Temperate Deciduous Forests
– The trees in temperate deciduous
forests shed all of their leaves in the
fall.
Chapter 21
Section 1 Terrestrial Biomes
Forests, continued
■ Taiga
– Taiga is cold but is warmer
than tundra and receives
more precipitation.
– Taiga is dominated by
coniferous forests.
Chapter 21
Grasslands
Section 1 Terrestrial Biomes
■ Temperate Grasslands
– Temperate grasslands occur in areas with cold
winters and hot summers.
– They are dominated by grasses and herds of grazing
animals.
■ Savanna
– Savannas are tropical grasslands with alternating
wet and dry seasons.
– They are dominated by herds of grazing animals.
■ Chaparral
– Chaparral is found in coastal regions with warm, dry
summers and mild winters.
– It is dominated by dense, spiny shrubs.
Chapter 21
Section 1 Terrestrial Biomes
Deserts
■ Deserts receive less than 25
cm (9.9 in.) of precipitation
per year.
■ Desert inhabitants have
adaptations for conserving
water.
Chapter 21
Section 2 Aquatic Ecosystems
Ocean Zones
■ The photic zone in the ocean
receives light, but the aphotic
zone does not.
■ The Intertidal Zone
– In the intertidal zone,
organisms must be able to
tolerate drying and pounding
by waves.
Chapter 21
Section 2 Aquatic Ecosystems
Ocean Zones, continued
■ The Neritic Zone
– The neritic zone receives nutrients
from the bottom of the ocean and
from land. It is the ocean’s richest
zone in terms of the number of
species and individuals.
■ The Oceanic Zone
– Production in the oceanic zone is
limited by a shortage of nutrients.
■ Estuaries
– Estuaries are very productive
areas where rivers and streams
flow into the sea.
Chapter 21
Section 2 Aquatic Ecosystems
Freshwater Zones
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Lakes and Ponds
Oligotrophic lakes are clear and lacking in nutrients.
Eutrophic lakes are rich in nutrients and are often murky.
Rivers and Streams
Rivers and streams are bodies of water that flow down an
elevation gradient within a watershed.
■ Freshwater Wetlands
– Freshwater wetlands are areas of land, such as marshes and
swamps, that are covered with fresh water for at least part of
each year.
Chapter 22
Section 1 An Interconnected Planet
Environmental Issues
■ Atmosphere
– Important parts of the
atmosphere are greenhouse
gases, which trap heat on Earth,
and the ozone layer, which shields
Earth from UV radiation.
– The atmosphere’s ability to trap
heat is called the greenhouse
effect.
Chapter 22
Section 1 An Interconnected Planet
Biodiversity
■ Biodiversity refers to the variety of life found in an
area.
■ Measuring Biodiversity
– Biodiversity can be measured in different ways,
including by species richness, species evenness, and
genetic diversity.
Chapter 22
Section 2 Environmental Issues
Pollution
■ Human impacts range from local
pollution to global change in
ecosystems.
■ Ozone Thinning
– Industrial chemicals called
chlorofluorocarbons (CFCs) act as
catalysts in chemical reactions that
break down O3 molecules in the ozone
layer.
– Most countries have banned CFCs,
and the ozone layer seems to be
recovering.
Chapter 22
Section 2 Environmental Issues
Pollution, continued
■ Global Warming
– The correlation of increasing
atmospheric CO2 and rising global
temperature suggests a cause-andeffect relationship.
– Considering several types of evidence,
many scientists have concluded that
increased CO2 levels have caused
warmer surface temperatures on
Earth.
Chapter 22
Section 2 Environmental Issues
Pollution, continued
■ Acid Precipitation
– Certain air pollutants cause acid
precipitation, which harms or kills
many organisms.
– Mostly due to sulfur from burning
fossil fuels
Chapter 22
Section 2 Environmental Issues
Pollution, continued
■ Land and Water Pollution
– The release of toxic chemicals,
such as DDT, into the biosphere
can impact ecosystems in many
ways, especially when chemicals
undergo biological magnification.
Chapter 22
Section 2 Environmental Issues
Ecosystem Disruption, continued
■ Extinction
– Human impacts on the environment are causing an increasing
number of extinctions.
– Important causes of extinctions are habitat destruction, the
transfer of invasive species to new habitats, harvesting, and
hunting.
– This loss of species has both known and unknown effects on
ecosystems.
■ Ecosystem Imbalances
– Species such as the sea otter that affect many other species in
a community are called keystone species.