Human impact on the Biosphere Hunting and Gathering… Early history – All materials necessary for...
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Transcript of Human impact on the Biosphere Hunting and Gathering… Early history – All materials necessary for...
Human impact on the Biosphere
• Hunting and Gathering… Early history– All materials necessary for survival
is taken from the local ecosystem• Forces evolution or extinction of prey
species
– Still practiced in indigenous tribes
Agriculture• Practice began ~11,000 years ago
with wheat, rice and potatoes– Quickly expanded into raising animals:
goats, pigs, cows, and horses– Allowed for the formation of larger
communities… civilization– Practice expanded dramatically in the
1800s and 1900s with plows and specialized equipment for the processing of materials… commerce• Monoculture practice ensues… growing
a single type of crop on a field
Green Revolution• The green revolution… Despite the
practice of monoculture farming and the development of specialized equipment, there were obvious food shortages in the mid 20th century– Fertilizers were introduced that
increased crop yields dramatically– Burbank and such introduced hybrid
varieties that were heartier and produced larger individual fruits
Limitations & Challenges faced by the Green Revolution
• Ecological impact– Practice of monoculture has led to
the evolution and rapid growth of the insect population leading to increased insecticide use
– Increased fertilization leads to eutrophication of ponds and lakes• Both practices endanger the water
supply
– Irrigation of arid land leads to saltification of the soil as minerals dissolve
– Irrigation of fields leads to loss of ground water needed for our communities• Supplies expected to dry up in 15-
20yrs
Industrial Revolution• Movement created convenience and
dependence on fossil fuels– Grew faster than our understanding of
the environment• Early practices included simply dumping
waste into the environment• Created the need for a waste disposal
system– Concentrates waste into toxic proportions
– Although there have been many advances, many ecologists are concerned that continued urban sprawl reduces farmable land and increases water use and pollution concentration