Download Understanding Our Environment

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 Hispaniola is an island that Christopher Columbus
took possession of during his voyage of 1492. He
was so enchanted with the lush green island that
he called it “The Spanish Island”.
 As the island was colonized, most of its indigenous
tribes died out from diseases and harsh working
conditions in Spanish gold mines.
 By 1517, the indigenous population was down to
14,000 from an original population of 250,000.
 There were now 14,000 African slaves and 1,000
Spanish colonists on the island.
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 Spanish and French colonists grew cane sugar,
indigo, cotton, and coffee, as these were the most
valuable commodities for trade.
 Much of the original forested land was cut down
and cultivated for farmland.
 The slave population of the island revolted in 1804,
gaining independence from French rule and their
own freedom. They named their new nation
“Ayiti”, meaning “mother of the Earth.”
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 The farmland was divided up in 15 hectare portions
to farmers. As this land was passed down and
divided up within families, the average farm size
shrunk to 1.5 hectares.
 Farmers began to overuse the land to continue
supporting themselves.
 When the land became infertile, they moved to
steep hills, overfarming them as well.
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 Today, only about 2% of the country’s original
forest cover remains. This forest remains at risk,
because most of the people depend on charcoal as
a source of heat.
 The lack of forests has made the country much
more susceptible to flooding, mudslides, and
erosion.
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 Species - All organisms genetically similar enough
to breed and produce live, fertile offspring in
nature.
 Population - All members of a species that live in
the same area at the same time.
 Biological Community - All populations living and
interacting in an area.
 Ecosystem - A biological community and its
physical environment.
 Biotic – Living or once-living factors
 Abiotic – Non-living factors
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 Biomes - Areas sharing similar climate,
topographic and soil conditions, and roughly
comparable communities.
 Includes all populations, communities, and abiotic
factors.
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 Productivity refers to the amount of biomass
produced in a given area during a given time.
 Food Webs are series of interconnected food
chains in an ecosystem.
 Trophic Level refers to an individual’s feeding
position in an ecosystem.
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 Organisms can also be identified by the kinds of
food they consume:
 Herbivores – Primary consumers; eat plants.
 Carnivores – Secondary or tertiary consumers; eat
other animals.
 Omnivores – Secondary or tertiary consumers, eat
both plants and animals.
 Decomposers - Breakdown complex organic matter
into simpler compounds. Feed on all trophic levels.
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 Most ecosystems have huge number of primary
producers supporting a smaller number of herbivores,
supporting a smaller number of secondary consumers.
 The Second Law of Thermodynamics states that some
energy is lost every time it is transferred in the form of
heat.
 Ecosystems not 100% efficient.
 The total energy transferred from one trophic level to the
next can be estimated with the 10% Rule.
 Only about 10% of the energy present in one trophic level can be
transferred successfully to the next trophic level.
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 The main abiotic factor in determining ecosystem
type is climate.
 Temperature, precipitation, humidity, and wind
over a long period of time.
 Different than weather (short-term)
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 Latitude is the distance away from the equator,
measured in degrees.
 Altitude is height above sea level.
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On the leeward side of the
mountain range, air descends,
warms, and releases little
moisture.
Prevailing winds
pick up moisture
from an ocean.
Moist habitats
Dry habitats
On the windward
side of a mountain range,
air rises, cools, and
releases moisture.
•Each side of a mountain range is affected differently by weather
patterns.
•The windward side is exposed to the wind first and gets more
moisture. The leeward side is left with very little moisture.
 Water gains and loses heat much more slowly than
air.
 Biomes near a large lake or ocean generally have
more stable temperatures.
 Often have higher levels of precipitation.
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 A climatograph is a
combination precipitation
and temperature graph for
a given biome.
 The average montly
precipitation for the area
is displayed as a bar graph,
while the average monthly
temperature is displayed
as a line graph.
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 Low moisture levels (less than 25cm of precipitation a
year)
 Rainfall is infrequent and unpredictable
 Often located on the leeward side of mountains
 High number of succulent plants
 Can survive for long periods without water
 Animals bury themselves underground and sleep
through the dry season.
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 Hottest and driest land biome
 Located near the equator
 Lowest amount of plant and animal life
 Seasonal temperature changes
 More moisture than tropical deserts, less than
grasslands
 Hot during the summer, freezing during winter.
 Similar precipitation to temperate deserts, but more
as snow and ice
Large desert cities
Soil destruction by offroad vehicles and urban
development
Soil sanitization from
irrigation
Depletion of underground
water supplies
Land disturbance and
pollution from mineral
extraction
Storage of toxic and
radioactive wastes
Large arrays of solar cells
and solar collectors used
to produce electricity
 More precipitation and cooler temperatures than
deserts.
 Temperature fluctuate depending on the time of day
and time of year.
 Mostly grasses, wildflowers, and shrubs.
 Few trees due to inadequate rainfall and high frequency
of fires.
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 Located near the equator, usually between desert and
rainforest biomes.
 Precipitation is very seasonal
 Wet season: Most active time for animals and plants
 Dry Season: Grass fires occur frequently
 Found in the interior of continents
 Three types of grasslands:
 Temperate means seasonal; Hot summers and cold
winters
 More consistent precipitation than tropical
grasslands.
 Very cold most of the year, windy
 Dominated by grasses, lichens, and herbs.
 Located north of the Arctic circle
 Underneath the topsoil, there is permafrost
 Permanently frozen soil
Fig. 5-14, p. 89
Natural Capital Degradation
Grasslands
Conversion of savanna and
temperate grasslands to cropland
Release of CO2 to atmosphere from
burning and conversion of
grassland to cropland
Overgrazing of tropical and
temperate grasslands by livestock
Damage to fragile arctic tundra by
oil production, air and water
pollution, and off-road vehicles
 Transition areas between arid grasslands and forests
 Hot, dry summers and cool, moist winters.
 Dominated with small, leathery, waxy leaves.
 Evergreen shrubs
 Fires common component of landscape.
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 Tropical Rainforests
 More than 200 cm annual rainfall
 Hot temperatures year-round.
 Usually located near the equator.
 Rapid plant growth causes the soil to be very nutrient
poor.
 Thin soil cannot support continued farming, and is
susceptible to erosion.
 Higher diversity of plants and animals than any other
biome.
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 Canopy
 Top layer of forest;
 Contains most of the fruits and flowers
 Also contains most of the animals
 Understory
 Receives only 5% of sunlight
 Few branches and leaves in this layer.
 Shrub Layer
 Shorter plants with wide, flat leaves to catch as much
sunlight as possible.
 Ground Layer
 Very bottom
 Mostly occupied by decomposers
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Emergent
layer
Harpy
eagle
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Height (meters)
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Toco
toucan
Canopy
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25
20
Understory
Wooly
opossum
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10
Brazilian
tapir
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Black-crowned
antpitta
0
Shrub
layer
Ground
layer
Fig. 5-17, p.
 Anywhere in the world where rainfall is plentiful
and there are four seasons.
 Deciduous trees shed leaves when water is scarce
or ground is frozen.
 High variety of trees and animals; not as diverse as
the rainforest
 Plants grow in layers
 Canopy: Tall, mature trees
 Understory: Small trees and shrubs
 Forest floor: Ferns, herbs, mosses
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 Large amounts of precipitation, high humidity,
and moderate temperatures.
 Occur farther away from the equator than tropical
rain forests and are not as warm.
 Example: Pacific Northwest
 Located near the Pacific Ocean
 Windward side of the Olympic Mountains
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 Located just below the Arctic Circle.
 Long, harsh winters
 Short growing season
 Mostly coniferous trees
 Produce cones instead of flowers
 Needle-like leaves
 Do not shed leaves in winter
 Waxy coating minimizes water loss.
 Allow snow to fall to the ground easier
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Fig. 5-19b, p.
Natural Capital Degradation
Forests
Clearing and degradation of tropical
forests for agriculture, livestock
grazing, and timber harvesting
Clearing of temperate deciduous
forests in Europe, Asia, and North
America for timber, agriculture, and
urban development
Clearing of evergreen coniferous
forests in North America, Finland,
Sweden, Canada, Siberia, and Russia
Conversion of diverse forests to
less biodiverse tree plantations
Damage to soils from off-road
vehicles
Fig. 5-20, p. 94
 Located anywhere the elevation rises 3000 feet or
more above sea level.
 Climate changes quickly occur over very short
distances
 Effect of elevation: Air gets colder and drier as
you get higher and higher
 Windward vs. leeward slopes: The side facing
the wind/weather patterns gets more moisture.
 Tops covered in ice and snow
 Reflects sunlight; Stay cooler and maintain
snow.
Natural Capital Degradation
Mountains
Landless poor migrating
uphill to survive
Timber extraction
Mineral resource extraction
Hydroelectric dams and
reservoirs
Increasing tourism (such
as hiking and skiing)
Air pollution from industrial
and urban centers
Increased ultraviolet radiation from ozone depletion
Soil damage from off-road
vehicles
Fig. 5-22, p. 95
 Ecotones - Boundaries between adjacent
communities.
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 Ecological Succession
 Primary Succession - A community begins to
develop on a site previously unoccupied by living
organisms.
 Secondary Succession - An existing community is
disrupted and a new one subsequently develops at
the site.
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 Pioneer Community – Community that develops
initially.
 Climax Community – Mature community that
develops after many years.
 Animals and plants are well-established K-
strategists
 Community becomes resistant to further change.
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