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Environmental Problems Today
1. Overusing Resources:-Two Main Types:
*Renewable: sunlight, forests, air, soil
*Nonrenewable: minerals, gems, & fossil fuels
* Right now, we over use both types, but esp. nonrenewable resources
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2. Energy Consumption From Fossil Fuels:
* Oil, coal, & natural gas provide 80% of energy used in industrialized countries
* NONRENEWABLE & causes pollution
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3. Pollution: = any physical, chemical, or
biological change that negatively affects organisms or negatively alters the environment
*Includes air, water, & soil pollution
*At least 1.1 billion people lack an adequate supply of safe drinking water
*More than twice that don’t have modern sanitation
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4. Global climate change:
* Human activities release carbon dioxide (CO2) & other greenhouse gases that trap heat in the atmosphere
* Over the past 200 years, atmospheric CO2 has increased by 35%
* By 2100… global temps will probably warm 1.5 to 6C (2.7-11 F)
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5. Overpopulation
*More people = increased use of resources = destruction of environment
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6. Loss of Biodiversity:
*Biodiversity: diversity of organisms (different species) in an area* Over the past century, more than 800
species have gone extinct & at least 10,000 species are now threatened
Tasmanian tiger- extinct 1936
Great Auk
- extinct 1844
tree kangaroo- endangered
cheetah- endangered
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*Biodiversity
*Number species on Earth known & described is ~1.7 million
*Estimated to actually be ~ 10 million
*INTERESTING FACT: Insects constitute the greatest number of species (nearly 1,000), followed by plants, arachnids, fungi, mollusks, and vertebrates 3:32
*Why Biodiversity is Important:
*We depend on healthy ecosystems and many organisms for balanced nutrient cycles & energy flow. *Every species is dependent on or depended upon by at least one other species.
*We use organisms for food, clothing, shelter, & medicine. *About 25% of drugs prescribed in the US
are derived from plants. Almost all antibiotics are derived from chemicals found in fungi. 3:36
*Tropical rain forests, coral reefs, coasts, & islands have high biodiversity*~50% world’s species live in tropical rain forests
*25 spots on Earth are “Biodiversity hotspots” = have high #s of endemic species & are threatened*Endemic = found in a limited area; risk extinction
*The hotspots include places like Madagascar, the Caribbean, and tropical forests in South America, China, the Philippines, etc.
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*Examples of Endemic Species
Lemurs of Madagascar Rock macaque of Taiwan
Galapagos Tortoises Philippine Crocodile2:58
*Biodiversity Threats:*Endangered species = likely to go extinct in near future
*~10,000 animals worldwide are “endangered”
*Threatened species = populations are declining
Threats to Biodiversity:
1. Habitat fragmentation & destruction
(Ex: Florida panther almost went extinct)
2. Pollution
3. Overharvesting & Poaching (illegal hunting)
(Ex: fishing industries)
4. Invasive species (not native to a particular region; Ex: Fire ants, kudzu)
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*Preventing Biodiversity Loss: 1.Captive breeding: zoos, conservation groups
2. Endangered Species Act (1973) – law against hurting, trading, or destroying habitat of endangered species
3. IUCN (International Union for the Conservation of Nature and Natural Resources) – founded 1948; works to protect species & habitats worldwide
4.CITES (Convention on International Trade in Endangered species) – treaty pass in 1973 by 170 countries; controls trade of wildlife
5. National Parks & Wildlife Sanctuaries3:24