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Learning Targets
20. Explain how habitat destruction, invasive species, and overexploitation
lead to a loss of species.
21. Describe how human population size relates to the impact humans have
on the environment.
22. Describe the causes of major environmental issues. (Climate Change,
Ozone depletion, Acid rain, Eutrophication, Biological magnification)
Biodiversity
• ALL organisms in the
ecosystem—with all
possible gene variants
• One of Earth’s greatest
resources!
• Threats
• Endangered Species
• Threatened Species
Threats to Biodiversity
• Habitat fragmentation
• Habitats isolated—
organisms can’t breed
• Smaller the habitat → fewer
species
• Biological magnification
• Toxic substances become
more concentrated as they
pass through food chain
• DDT & Rachel Carson
Threats to Biodiversity (cont.)
• Introduced species
• Invasive species—
reproduce rapidly &
outcompete natives
• Zebra mussels!
• Thistle, purple
loosestrife, kudzu
Other problems
• Ozone depletion
• CFC’s degraded
atmospheric ozone—
lets too much UV in→
cancers
• Global warming
• Greenhouse gases -cause atmosphere to
warm up, ice shelves
melt, deserts spread
Resource Management
• Renewable Resources
• Can be regenerated or
replenished
• Non-renewable Resources
• Cannot be replaced
• Ex. Fossil fuels
• Sustainable development
• Using resources without
using them up
• No overexploitation
Resource Management:
Conservation
• Habitat protection
• Protect Keystone
species
• Species that can crash
the ecosystem
• Understand edge
effect
• Reduces habitat in
wooded areas
• Quail, pheasant
• Habitat restoration
Land Resources
• Erosion
• Plowing leaves soil
exposed—erodes
• Loss of fertile topsoil
• Results in
desertification
Forest Resources
• Provide wood, oxygen,
niche for many
organisms
• Deforestation
• Loss of wood/oxygen &
biodiversity
• Erosion of soil
Fishery Resources
• HUGE food resource
• Overfishing will
eliminate food fish by
mid-century & crash
ocean ecosystems
• Solution:
Aquaculture—grow
food fish!
• Not problem free