Post on 05-Apr-2018
7/31/2019 Chapter 9 Bio
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Human activities often effect wholeecosystem
With great advancements in themedical field, modern farming techniques and better infrastructure, the world’s population has grown toover 6 billion today
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The rapid destruction of woodlands / the removal of trees from forest is
known as deforestation
Every year, vast areas of forests are
cleared to make way for agriculture and development
7/31/2019 Chapter 9 Bio
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Despite their importance, it has beenestimated that more than 50 millionacres of rainforests are destroyed /
seriously degraded every year
7/31/2019 Chapter 9 Bio
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CAUSES SOIL EROSION,
LANDSLIDES
7/31/2019 Chapter 9 Bio
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IMPROPER
DEVELOPMENT
AND PLANNIG
THE ABSENCE
OF PLANT
ROOT SYSTEM
SOIL
EROSION
WHEN HEAVY
RAINS FOR A
LONG PERIOD
THE TOP LAYER
OF THE SOIL
SCRUMBLES
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LEADS TO
LANDSLIDES
THE ERODED SOIL
IS THEN CARRIED
BY MOVING WATER
DEPOSITED AT
THE BOTTOM
OF RIVERS
FLASH
FLOODS
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The destruction of millions of hectares of forest by human activitiesmeans:
the removal of bases of numerousfood webs
the loss of habitats of flora and fauna
the extinction of countless sp. and varieties of plants and animals
RESULTS IN THE LOSS OF
BIODIVERSITY
7/31/2019 Chapter 9 Bio
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THE
REMOVAL
OF PLANTS
DISRUPTS THE
NUTRIENTS
CYCLES
LEVEL OF
ATMOSPHERIC
CO2
LEVEL OF
ATMOSPHERIC
O2
THE RECYCLING
OF NITRATES &
OTHER IONS
DISRUPTS THE CARBON &
NITROGEN CYCLES
7/31/2019 Chapter 9 Bio
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deforestation disrupts the normalweather patterns, creating hotter,drier weather and causing climatic
changes the removal of trees reduces transpiration, rainfall and the rate at
which plants absorb CO2 from theatmosphere during photosynthesis
CAUSES CLIMATIC CHANGES
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this lead to increase in the level CO2 in the atmosphere. High level of CO2
prevent heat from escaping from theatmosphere. This is known as the greenhouse effect which is believed
to lead to global warming
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forest clearing and burning of woodresult in air pollution and release moreCO2 into the atmosphere
Burning of trees in the tropics addsabout 25% more CO2 to theatmosphere
7/31/2019 Chapter 9 Bio
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The burning of fossil fuels adds about75% of to the atmosphere
An increase in level is associated with the greenhouse effect and globalwarming
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Excessive use of land for intensivefarming decreases the space andresources available for other species
In intensive farming, farmers oftenuse inorganic fertilizers, which
contain nitrates, phosphates andpotassium ions, to improve crop yields
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Since nitrate and ammonium ions are
highly soluble, they do not remain in the soil for long and are quicklyleached into the surrounding rivers
and lakes
This leads to eutrophication.
Eutrophication is discussed later in the section on water polllution
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An increase in human population
generates an increase in bothdomestic and industrial waste
The dumping waste in landfills poses a great danger to living organisms as
toxic substances and other pollutantsfrom the dumpsites leak into the ground and eventually pollute thenearby water sources