Transcript Chapter 5 Gases

Biology
Concepts and Applications | 9e
Starr | Evers | Starr
Chapter 43
The Biosphere
© Cengage Learning 2015
© Cengage Learning 2015
43.1 What Determines Air Circulation
Patterns?
• Climate
– The average weather conditions (cloud cover,
temperature, humidity, wind speed) over time
– Regional climates are influenced by factors
that affect winds and ocean currents (intensity
of sunlight, distribution of land masses and
seas, and elevation)
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43.3 What Are the Major Biomes?
• Biomes
– Communities with similar climates and
vegetation
– Evolve in widely separated regions as a result
of similar environmental factors
– Discontinuous region characterized by its
climate and dominant vegetation
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What Are the Major Biomes?
© Cengage Learning 2015
What Are the Major Biomes?
• Differences between biomes
– Rainfall and temperature are the main
determinants of the type of biome in a given
region
– Soils also influence biome distribution
• Properties of soils vary depending on the types,
proportions, and compaction of mineral particles
and varying amounts of humus
– Climate and soils affect primary production, so
primary production varies among biomes
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43.4 What is the Most Productive Biome?
• Tropical rainforests
– Form between latitudes 10° north and south in
Africa, East Indies, Asia, and South and
Central America
– 130 to 200 centimeters (50 to 80 inches) of
rain falls throughout the year
– Highly productive and species-rich biome in
which year-round rains and warmth support
continuous growth of evergreen broadleaf
trees
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What is the Most Productive Biome?
• Tropical rain forest is the most productive,
structurally complex, and species-rich
biome
– Photosynthesis occurs year-round, but trees
often form a closed canopy that blocks light
from the forest floor
– Deforestation is an ongoing threat to tropical
rain forests in developing countries with fastgrowing human populations
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What is the Most Productive Biome?
O horizon:
Sparse litter
A–E horizons:
Continually leached;
iron, aluminum left
behind impart red
color to acidic soil
B horizon:
Clays with silicates,
other residues of
weathering
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43.5 What Types of Forests Occur in
Cooler Climates?
• Temperate deciduous forests
– Northern Hemisphere biome in which the
main plants are broadleaf trees that lose their
leaves in fall and become dormant during cold
winters
– Deciduous plant sheds leaves annually, prior
to a season when cold or dry conditions would
not favor growth
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What Types of Forests Occur in Cooler
Climates?
• Temperate deciduous forests
– Form where 50 to 150 centimeters (20–60
inches) of precipitation falls throughout the
year
– Winters are cool and summers are warm
– Leaves often turn color before dropping in
autumn
– Trees remain dormant in winter; flower and
put out new leaves in spring
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What Types of Forests Occur in Cooler
Climates?
• Coniferous forests
– Conifers withstand harsher conditions than
broadleaf trees, so they grow farther north
and at higher altitudes
– The coniferous forest that extends across
northern Asia, Europe, and North America –
known as the boreal forest or taiga – is the
most extensive land biome
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What Types of Forests Occur in Cooler
Climates?
• Coniferous forests
– Conifers (evergreen trees with seed-bearing
cones) such as pine, fir, and spruce are the
main plants in coniferous forests
– Conifers are adapted to conserve water
during drought or times when the ground is
frozen
• Winters are long, cold, and dry; and most rain falls
in the cool summer
– Moose are the dominant grazers
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What Types of Forests Occur in Cooler
Climates?
A North American temperate deciduous forest in fall.
B Boreal forest (taiga) in Siberia.
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43.6 What Are the Fire-Adapted Biomes?
• Grasslands
– Form in the interior of continents between
deserts and temperate forests
– Perennial grasses adapted to fire, grazing,
strong winds, and infrequent rain are the main
plants in grasslands
– Temperate grasslands are warm in summer,
cold in winter, with rains throughout the year
– Grass roots help hold thick topsoil in place,
preventing erosion by constant winds
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What Are the Fire-Adapted Biomes?
A
B
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43.7 What Is the Driest Biome?
• Deserts
– Tend to have low humidity, large daily
temperature shifts, and little topsoil
– Receive less than 10 centimeters (4 inches)
of rain per year
– Most are located at about 30° north and south
latitude, or in rain shadows
– Plants that have water-storing and conserving
adaptations predominate
© Cengage Learning 2015
What Is the Driest Biome?
• Deserts
– Diversity is highest in regions where moisture
is available in more than one season
– CAM plants (cactuses, agaves, euphorbs)
conserve water by opening stomata only at
night when temperature declines
– Annuals have a life cycle that allows them to
sprout and reproduce in the short time that
the soil is moist
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What Is the Driest Biome?
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43.8 What Is the Coldest Biome?
• Arctic tundra
– Highest-latitude Northern biome
– Low, cold-tolerant plants survive with only a
brief growing period
– Forms between the polar ice cap and belts of
boreal forests in the Northern Hemisphere
– Snow covers arctic tundra up to nine months
of the year
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What Is the Coldest Biome?
• Arctic tundra
– Only the surface layer of soil thaws during
summer – below that lies permafrost up to
500 meters (1,600 feet) thick
– Permafrost
• Prevents drainage
• Cool and anaerobic conditions slow decay
• Organic remains build up
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What Is the Coldest Biome?
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43.9 What Are the Main Types of
Freshwater Ecosystems?
• Freshwater ecosystems
– Gradients in light penetration, temperature,
and dissolved gases affect the distribution of
life in aquatic habitats
– Include lakes, streams, and rivers
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What Are the Main Types of Freshwater
Ecosystems?
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What Are the Main Types of Freshwater
Ecosystems?
• Dissolved oxygen
– One of the most important factors affecting
aquatic organisms
• More oxygen dissolves in cooler, fast-flowing water
than in warmer, still water
• When water temperature increases or water
becomes stagnant, aquatic species with high
oxygen needs suffocate
• Smoothly flowing water, holds less oxygen than
water that mixes with air as it runs over rocks
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43.10 What Are Coastal Ecosystems?
• Near the coasts of continents and islands,
concentrations of nutrients support highly
productive aquatic ecosystems
• Estuary: an enclosed coastal region where
seawater mixes with fresh water from
rivers and streams
– A highly productive ecosystem where nutrientrich water from a river mixes with seawater
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What Are Coastal Ecosystems?
• Estuaries
– Marine nurseries; many larval and juvenile
invertebrates and fishes live in them
– Detrital food chains predominate
– Primary producers include algae and other
phytoplankton, along with plants that tolerate
submergence at high tide
© Cengage Learning 2015
What Are Coastal Ecosystems?
A Cordgrass
(Spartina) in a
South Carolina salt
marsh. Salt taken
up in water by
roots is excreted
by glands on the
leaves.
B Mangroves along
the shore in Florida.
Specialized cells at
the surface of some
exposed prop roots
allow gas exchange
with air.
© Cengage Learning 2015
43.11 What are Coral Reefs?
• Coral reefs: highly diverse marine
ecosystem
– Wave-resistant formations that consist
primarily of calcium carbonate secreted by
coral polyps
• Reef-forming corals live mainly in shallow, clear,
warm waters between latitudes 25° north and 25°
south
– A healthy reef is home to living corals and a
quarter of all marine fish species
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What Are Coral Reefs?
© Cengage Learning 2015
What Are Coral Reefs?
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Biology
Concepts and Applications | 9e
Starr | Evers | Starr
Chapter 44
Human Effects on the Biosphere
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44.1 Why Are So Many Species
Threatened of Endangered?
• All over the world, humans are replacing
wildlife habitat with our dwellings,
factories, and farms
• We also put species at risk
– Competing with them for resources
– Overharvesting them
– Introducing non-native competitors
• The rate of species extinctions is rising;
many types of biomes are threatened
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Why Are So Many Species Threatened of
Endangered?
• A species is considered endangered when
one or more of its populations have
declined or are declining
– Endangered species
• A species that faces extinction in all or a part of its
range
– Threatened species
• Species likely to become endangered in the near
future
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What Are the Effects of Desertification and
Deforestation?
A Dust cloud in the Great Plains during the 1930s.
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B Dust blows across the Atlantic from North Africa.
What Are the Effects of Desertification and
Deforestation?
• Tropical forests continue to disappear at
an alarming rate
• In addition to immediate destruction of
forest organisms, deforestation
encourages flooding, and raises risk of
landslides in hilly areas
• Deforestation also affects local weather –
temperatures rise, and reduced
transpiration results in less rainfall
© Cengage Learning 2015
What Are the Effects of Desertification and
Deforestation?
• Forests take up and store huge amounts
of carbon, so deforestation also
contributes to global climate change
– Deforested areas also become nutrient-poor
• Experimental deforestation increased
runoff of essential soil nutrients such as
calcium (compared with undisturbed
forest)
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What Are the Effects of Desertification and
Deforestation?
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44.3 How Does Trash Degrade Habitats?
• Trash:
– Buried in the ground (such as lead from
batteries) can contaminate groundwater
– Dumped at sea (such as plastics) harms
marine life
• Plastic and other garbage that enters our
coastal waters persists for many years
– Avoid buying plastics, or be sure to recycle or
dispose of them properly
© Cengage Learning 2015
How Does Trash Degrade Habitats?
A
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B
44.4 What Are the Effects of Acid Rain?
• Pollutants disrupt physiological processes
of organisms
– Sulfur dioxides from coal-burning power
plants, and nitrogen oxides from burning gas
and oil, are common air pollutants
– Pollutant
• Substance that is released into the environment by
human activities and interferes with the function of
organisms that evolved in the absence of the
substance or with lower levels
© Cengage Learning 2015
What Are the Effects of Acid Rain?
• Dry acid deposition: dry dust particles
coated with airborne sulfur and nitrogen
• Wet acid deposition (acid rain): pollutants
combine with water and fall as acidic
precipitation
• Acid rain
– Low pH rain that forms when sulfur dioxide
and nitrogen oxides mix with water vapor in
the atmosphere
© Cengage Learning 2015
What Are the Effects of Acid Rain?
• Acid rain in aquatic habitats
– Prevents fish eggs from developing
– Kills adult fish
• Acid rain in forests
– Burns tree leaves
– Makes trees more susceptible to insects and
pathogens
© Cengage Learning 2015
44.5 What Are the Effects of Ozone
Depletion and Pollution?
• Ozone is said to be “good up high, but bad
nearby”
– In the upper atmosphere, the ozone (O3) layer
absorbs most incoming ultraviolet (UV)
radiation that damages DNA and causes
mutations
– Near the ground, it is a harmful pollutant
© Cengage Learning 2015
What Are the Effects of Ozone Depletion
and Pollution?
• In the mid-1970s, scientists noticed that
Earth’s ozone layer (10.5 to 17 miles
above sea level) was thinning, particularly
over Antarctica (the “ozone hole”)
• In 1987, countries worldwide agreed to
phase out production of
chlorofluorocarbons (CFCs) and other
ozone-destroying chemicals – but existing
CFCs break down very slowly
© Cengage Learning 2015
44.6 What Are the Effects of Global
Climate Change?
• Climate change is the most widespread
threat to habitats worldwide
– Thermal expansion/meltwater from glaciers
flood coastal wetlands
– Temperature changes disrupt life-cycle events
(e.g., tree flowering, animal migration, and
breeding seasons)
– Some species are moving to higher latitudes
or elevations; those that cannot move are
stressed or dying
© Cengage Learning 2015
What Are the Effects of Global Climate
Change?
• Many weather patterns are expected to
change as rising land and sea
temperatures affect evaporation, winds,
and currents
• Examples
– Extremes in rainfall patterns: periods of
drought interrupted by unusually heavy rains
– Increase in hurricane intensity
© Cengage Learning 2015
What Are the Effects of Global Climate
Change?
Muir Glacier in Alaska (1940)
Muir Glacier in Alaska (2004)
© Cengage Learning 2015
What Is Conservation Biology?
• Healthy ecosystems are essential to
human survival:
– Produce our oxygen and food
– Remove, decompose, and detoxify wastes
– Prevent erosion and reduce risk of flooding
– Allow for new medicines to be derived from
compounds in wild species
– Encourage plant breeders to use genes in
wild species to protect and improve crops
© Cengage Learning 2015
What Is Conservation Biology?
• People often oppose environmental
protections because they fear adverse
economic consequences
• Conservation biologists help determine
which regions should be targeted for
protection first by identifying hot spots
– Threatened region with great biodiversity that
is considered a high priority for conservation
efforts
© Cengage Learning 2015
What Is Conservation Biology?
© Cengage Learning 2015
44.8 How Can We Reduce Our Impact?
• Ultimately, the health of our planet
depends on our ability to recognize the
principles of energy flow and resource
limitation
• The goal is living sustainably
– Meeting the needs of the present generation
without reducing the ability of future
generations to meet their own needs
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How Can We Reduce Our Impact?
• People in industrial nations use enormous
quantities of resources, and the extraction,
delivery, and use of these resources has
negative effects on biodiversity
– Example: In the U.S., an average new home
contains about 500 pounds of copper wiring
and plumbing
• Strips vegetation and soil; produces waste; causes
air and water pollution
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How Can We Reduce Our Impact?
A
© Cengage Learning 2015
B
Ecological
Footprint
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© Cengage Learning 2015
© Cengage Learning 2015
Figure 19.22
44.9 A Long Reach
• In the Arctic, unusually warm temperatures
are affecting the seasonal cycle of sea ice
melting and formation
– Polar bears can only reach their main prey by
traveling across ice
• Other threats – high amounts of mercury
and organic pesticides are carried to polar
regions by winds and ocean currents
– Have been found in tissues of polar bears
© Cengage Learning 2015
A Long Reach
• Eight countries, including the U.S., control
parts of the Arctic and have rights to
extensive oil, gas, and mineral deposits
– Melting ice sheets make it easier to remove
minerals and fossil fuels from the Arctic
– Extracting these resources will further harm
Arctic species that are already threatened by
global climate change
© Cengage Learning 2015
© Cengage Learning 2015
11/26 Friday Schedule
Populations
40
11/28
No Class
12/3
41
12/5
Trophic Levels
Ecology
Succession
Lab Review
12/10 Biomes & Human 43&44 12/12
Effect
Lecture Review
Lab Final Exam
12/17
Make up class if
needed
Final Exam
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12/19
42