Transcript Humans in the Biosphere

HUMANS IN THE
BIOSPHERE AND
SUSTAINABILITY
HOW HAVE HUMANS
CHANGED THE EARTH?
WHAT DO THESE TERMS
MEAN?
Soil erosion
Desertification
Deforestation
Overfishing
Pollution
Acid Rain
DESERTIFICATION
 Occurs in DRY
climates
 Once fertile soils
become deserts
 Caused by a
combination of
farming, drought,
and overdrawing
groundwater
*VIDEO*
DEFORESTATION
 Loss of trees/forest
 What happens if there
are no trees or roots?
(why is vegetation
important?)
 SOIL EROSION, soil is
exposed to heavy rain,
especially in tropical
areas!
*Video*
OVERFISHING
• Bycatch: organisms
caught accidentally (as a
Byproduct)
• Usually discarded
• Reduced biomass in
trophic levels
• Habitat
modification/destruction
*Video!*
Save me!
Pollution
Examples: DDT; garbage
island
*video*
Acid Rain
Affects:
Plant life & soils
Aquatic environments
Statues
Could cause cancer?
ACID RAIN IN NORTH AMERICA
BIODIVERSITY:
THE DIVERSITY OF LIFE
Several types of biodiversity
Environmental diversity
Species diversity
Genetic diversity
( types
of habitats, ecosystems )
Biodiversity has given us foods, medicines, and all
kinds of products. Who knows what else it could
provide for us?
WHAT ARE SOME THREATS TO
BIODIVERSITY?
1. Habitat changes, fragmentation,
destruction
2. Hunting species to endangerment or
extinction
3. Introducing toxic substances into food
webs (pollution)
4. Introducing foreign species into
environments (invasive species)
BIODIVERSITY HOT SPOTS
ENDANGERED SPECIES
In the past many species went extinct
due to excessive hunting
What threats are there to species today?
Development
Deforestation
Expansion
Decreasing amounts and availability of
resources
Climate Change