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 (types of habitats, ecosystems) Species diversity Genetic diversity 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? Habitat changes, fragmentation, destruction Hunting species to endangerment or extinction Introducing toxic substances into food webs (pollution) Introducing foreign species into environments (invasive species)

Biodiversity Hot Spots

In the past many species went extinct due to excessive hunting 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