chapter 59 The Biosphere

Question 1

Effects of Sun, Wind, Water

Answer 1

Biosphere: includes all living communities on Earth
Global patterns of life on Earth are influenced by
The amount of solar radiation that reaches different areas
Patterns of global atmospheric circulation which influence oceanic circulation

Question 2

Earth receives energy from the Sun
Solar radiant energy passes through the atmosphere and its intensity and wavelength composition are modified
About 1/2 of the energy is absorbed within the atmosphere
UV-B is strongly absorbed by the ozone

Answer 2

Some parts of the Earth’s surface receive more energy from the Sun than others
This has a great effect on climate
Angle of incidence: how the Sun’s rays strike the spherical Earth

Question 3

Earth’s orbit around the Sun and its daily rotation on its own axis affect climate
Progression of seasons occurs on all parts of the Earth

Answer 3

Global circulation patterns
Hot air rises relative to cooler air
Heating at the equator causes air to rise from the surface to high in the atmosphere
Rising air is rich in water vapor
Warm air holds more water than cold
Intense solar radiation at the equator provides the heat needed for water to evaporate

Question 4

After the warm moist air moves from the surface at the equator
Warm air moves north and south
Cooler air flows toward the equator from both hemispheres
Air descends at 30˚ latitude – desert regions of the earth
At 60˚ latitude air begins to rise again

Answer 4

The Coriolis effect: the curvature of the paths of the winds due to Earth’s rotation
Northern hemisphere: counterclockwise – winds curve to the right of their direction of motion
Southern hemisphere: clockwise –winds curve to the left; blow westward as well as toward the equator

Question 5

Regional and local differences affect terrestrial ecosystems
Rain shadows
Rain falls as air rises
Remains dry on the leeward side of the mountain

Answer 5

Monsoons – seasonally shifting winds
Asia is so huge that heating and cooling of its surface causes massive regional shifts in wind patterns
Winds blow off the water into the interior in the summer
Winds blow off land onto the water in the winter
Winds affect rainfall patterns
Duration
Strength

Question 6

Elevation: temperature and other conditions change with elevation
Air temperature falls about 6˚C for every 1000 m increase in elevation

Answer 6

Microclimates: highly localized sets of climatic conditions
Gaps in forest canopy
High air temperature and low humidity
Under a log in the forest
Low air temperature and high humidity

Question 7

Biomes

Answer 7

Biomes: a major type of ecosystem on land
Each biome has a characteristic appearance
Defined largely by sets of regional climatic conditions
Biomes are named according to their vegetational structures
8 principle biomes with 6 others

Question 8

Tropical rain forests
140–450 cm rain/yr
Richest ecosystems on land
High temperature and high rainfall
Very high diversity:  1200 species of butterflies in a single square mile

Answer 8

Savanna
50–125 cm rainfall/yr
Tropical or subtropical grasslands
Occur as a transition ecosystem between tropical rainforests and deserts
Serengeti of East Africa

Question 9

Deserts
25–40 cm rainfall/yr; unpredictable
Plants and animals cannot depend on any rainfall
30˚N and S latitudes – due to global air circulation patterns
Due to rain shadows
Vegetation sparse, animals adapted to little water availability

Answer 9

Temperate grasslands or prairies
Rich soils
Grasses with roots that penetrate deep into the soil
In North America converted to agricultural use
Adapted to periodic fire

Question 10

Temperate deciduous forests
Mild but seasonal climates (warm summers and cold winters), plus plentiful rains
Temperate evergreen forests
Occur along coastlines with temperate climates

Answer 10

Taiga and tundra
Both stretch in unbroken circles around the entire globe
Taiga—northern forests, coniferous trees;
one of the largest biomes; severe and long winters
Tundra—frozen treeless area
permafrost—soil ice that persists throught all seasons

Question 11

Human Impacts: Pollution

Answer 11

Human impacts can cause adverse changes in ecosystems
DDT: highly effective insecticide, sprayed in United States after WWII
DDT is oil soluble and biomagnifies in the food chain
Result of use
Populations of ospreys, bald eagles, and brown pelicans plummeted

Question 12

Biomagnification of DDT concentrations in the food chain

Predatory bird species were affected because it made their eggshells so thin that the shells broke during incubation

Answer 12

Freshwater habitats are threatened by pollution and resource use
Point source pollution: comes from an identifiable location
Factories
Sewage-treatment plants
Laws and technologies can be applied because the source is known

Question 13

Diffuse pollution: is exemplified by eutrophication caused by excessive run-off of nitrates and phosphates
Dissolved oxygen declines
Fish species change, carp take the place of more desirable species
Can originate from thousands of lawns, farms, golf clubs, etc.
Solutions depend on public education and political action

Answer 13

Pollution from coal burning: acid precipitation
When coal is burned, sulfur oxide is released
Sulfur oxide combines with water in the atmosphere to create sulfuric acid
Mercury emitted in stack smoke is a second potential problem
Mercury can interfere with brain development in human fetuses and infants

Question 14

Acid precipitation and mercury pollution affect freshwater ecosystems
pH levels below 5.0, many fish species and other aquatic animals die or are unable to reproduce
Mercury accumulates in the tissues of food fish: dangerous to public health

Answer 14

Terrestrial ecosystems are threatened by deforestation

Single greatest problem is deforestation by cutting or burning

Question 15

Deforestation consequences
Loss of habitat
Major contributing factor in increased desertification
Loss of nutrients from soils
Nutrient enrichment of bodies of water downstream
Disruption of the water cycle
Acid rain

Answer 15

Overfishing of the ocean
Single greatest problem in the ocean realm
Poaching on terrestrial animals increases when fish populations decline

Question 16

Aquaculture is only a quick fix
Dietary protein needs of many aquacultured fish are met with wild-caught fish
Often damage natural ocean ecosystems: clearing of mangrove swamps for aquaculture area

Answer 16

Pollution effects in the ocean
Plastic found washed up on beaches in remote areas
Waters are laced with toxic chemicals
Biopsy of tissue from Arctic killer whales reveal high levels of pesticides and flame-retardant chemicals

Question 17

Destruction of coastal ecosystems
Estuaries subjected to severe eutrophication
Destruction of salt marshes
Major contributing factor to hurricane destruction along the coast of Louisiana
Had marshes been present, Katrina might not have caused so much damage

Answer 17

Stratospheric ozone depletion

Ozone hole: over Antarctica between 1/2 to 1/3 of original ozone concentrations are present

Question 18

Over United States
Ozone concentration has been reduced by about 4%
Stratospheric ozone is important because it absorbs UV radiation (UV-B)
UV-B damages tissue, increases risks for
Skin cancer: 1% drop in ozone leads to a 6% increase in skin cancer
Detrimental to amphibians

Answer 18

Ozone depletion and CFCs: Major cause of ozone depletion are chlorine- and bromine-containing compounds in the atmosphere (chlorofluorocarbons)
Use of CFCs are being phased out in many countries
CFCs liberate free chloride atoms which breaks down ozone molecules (O3O2)
CFCs are chemically stable in the atmosphere for many years
Ozone depletion will continue to occur until all of the CFCs are broken down

Question 19

Climate Change

Answer 19

CO2 and other gases in the atmosphere maintain the Earth’s average temperature at 25˚C higher than it would be without these gases
Human activities are now changing the composition of the atmosphere; increasing the CO2 and other gas levels
Because of the increase, global temperatures are increasing, causing global warming

Question 20

Based on a variety of different scenarios, computer models predicted that global temperatures would increase 1.1°C to 6.4°C (2.0–11.5°F) by the end of this century
Some countries will come out ahead, others will come out behind

Answer 20

Carbon dioxide is the major greenhouse gas
Other atmospheric gases also involved
All authorities agree that the cause of this steady rise in atmospheric CO2 is the burning of coal and petroleum products by the increasing (and increasingly energy-demanding) human population

Question 21

How CO2 affects temperature
CO2 absorbs electromagnetic radiant energy
Earth receives radiant energy from the Sun
Earth also emits radiant energy
The Earth’s temperature will be constant only if the rates of these two processes are equal

Answer 21

The atmosphere allows in short wave radiant energy from the Sun, but does not allow the long wave radiant energy from the Earth to escape
This is the same principle as a Greenhouse
Short wave – in, long wave – cannot get out, increase in temperature in the greenhouse

Question 22

Other greenhouse gases
Methane: 20 times the heat trapping properties of CO2, less concentration in the atmosphere, less long-lived
Methane is produced globally in anaerobic soils and fermentation reactions of ruminant mammals
Methane is locked up in permafrost
Sudden release will cause large perturbation in global temperature

Answer 22

Other greenhouse gases
Nitrous oxide: agricultural use of fertilizers is the largest source
Energy consumption
Industrial use
Evidence confirms global warming
Ice free seasons 2.5 weeks longer
Ice at the North Pole decreased
Glaciers decreasing in size

Question 23

Global temperature change has affected ecosystems in the past and is doing so now
Shift in species’ geographic ranges
Migratory birds arrive earlier at their summer breeding grounds
Insects and amphibians breed earlier
Wild fruit fly populations – changes in gene frequency
“Bleaching” of reef-building c

Answer 23

Problems
Rate of warming today is rapid
Evolutionary adaptations for species survival may not have time to occur
Natural areas no longer cover the whole landscape
Species that shift to higher altitudes may have reached the peak of the mountain
Species’ habitat disappears entirely

Question 24

Problems
Rate of warming today is rapid
Evolutionary adaptations for species survival may not have time to occur
Natural areas no longer cover the whole landscape
Species that shift to higher altitudes may have reached the peak of the mountain
Species’ habitat disappears entirely

Answer 24

Possible effects on human species
Rising sea levels: 200 million people would be affected by increased flooding
Coastal cities and entire islands could be submerged
Frequency or severity of extreme events will increase (heat waves, drought, hurricanes, El Niño)

Question 25

Effects on agriculture
Positive: more CO2 tends to increase growth of some crops
Increase pollen production causing more severe allergies
More droughts in some regions
Decrease in crop production in tropical areas

Answer 25

Human health
Frequent flooding = loss of safe drinking water
Cholera and other epidemics may occur more often
Tropical diseases may invade nontropical countries
Malaria
Dengue fever