Chapter 9 Bio

7/31/2019 Chapter 9 Bio

http://slidepdf.com/reader/full/chapter-9-bio 1/25



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





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



Despite their importance, it has beenestimated that more than 50 millionacres of rainforests are destroyed /

seriously degraded every year





CAUSES SOIL EROSION,

LANDSLIDES





CAUSES FLASH FLOODS





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



LEADS TO

LANDSLIDES

THE ERODED SOIL

IS THEN CARRIED

BY MOVING WATER

DEPOSITED AT

THE BOTTOM

OF RIVERS

FLASH

FLOODS



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



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



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







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



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



The burning of fossil fuels adds about75% of to the atmosphere

An increase in level is associated with the greenhouse effect and globalwarming





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



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



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



Documents

Chapter 9 Bio