Human activities can be harmful for the environment: Deforestation, over harvesting, introduction ofimported (invasive) species, pesticides use, fertilizeruse, air pollution, water pollution, industrial wastes,
1. deforestation: destroying forests by cutting down many many trees.
Deforestation destroys animal’s habitats,increase carbon dioxide in air, destroysrare species and new medicinal plants..
Solutions to deforestation: • Cut down less trees. • plant more trees to replace cut ones. • Pass laws to prevent over harvesting of trees. • Created protected forest areas where NO ONE can cut.
2.Over harvesting (Over hunting, over fishing): exploiting an organism too much. Ex: elephants killed for tusks and left to rot!
Over harvesting (Over hunting, over fishing) can lead to endangered or extinct species. Ex: elephants killed for tusks and left to rot!
Solutions to Over harvesting (Over hunting, over fishing): • Pass laws to protect animals. • Do not hunt too many animals. • Create protected areas for animals.
3. Imported species (invasive species):taking animals from their natural home and putting them in a new environment without any natural predators.
Examples of Imported species: rabbits & the Cane toads in Australia.
24 European rabbits were brought on purpose to Australia, they had no natural enemies. They bred and bred and bred until there were thousands (millions?) they almost destroyed Australia’s ecosystem .
cane toads were brought on purpose to Australia, they had no natural enemies. They bred and bred and bred until there were thousands (millions?) they almost destroyed Australia’s ecosystem .
sometimes imported species are brought by accident: the zebra mussel, gypsy moth, Japanese beetle, the fire ants.
sometimes imported species are brought by accident: the zebra mussel, gypsy moth, Japanese beetle, the fire ants. All are threats in their new environments!
Solution to imported (invasive ) species:• Don’t remove animals or plants from their natural habitats.• Pass laws against importing species.
Technology: has improved thequality of life for humans…
Humans need electricity to run ourmachines…. But there are tradeoffs (consequences)
Producing electricity (a good thing) ismostly made in “bad ways”: burning fossil fuels & nuclear energy.
The Fossil fuels are coal, oil, gasoline and natural gas…
Burning fossils fuel releases carbondioxide (CO2) and other “greenhouse gases”.
Nuclear energy does NOT pollute theair, but the radioactive wastes remainsdeadly for tens of thousands of years!
Solutions: make electricity using alternative sources:• Solar energy• Wind power• Hydroelectric (water) power.• Conserve electricity (turn off lights/appliances when you DON’T need then)
industrialization has improvedthe quality of life for humans…
Factories produce clothes, TV’s, DVD’s, computers, furniture… But there are trade-off (negative consequences)….
Factories produce air pollution, water pollution, solid waste.
Air pollution: poisonous gases released into the air from factories or from cars.
Air pollution is bad because it: causesglobal warming, ozone layer- depletion & acid rain!
global warming: carbon dioxide (CO2) andother greenhouse gases are raising average global temperatures; leading to severe unpredictable weather, the ice caps melting, rising sea levels and flooding.
CO2 levels have risen tremendously inmodern times. This is associated with global warming!
The ozone layer protects us from UV radiation.
CFC gases from spray cans deplete (destroy) the ozone layer. levels of skin cancer may rise without ozone layer protection!
acid rain: car exhaust, factory smoke, forest fire smoke add chemicals to the air. Thechemicals mix in the clouds and fall as acid rain.
Acid rain is bad because it destroysplants, kills fish when it gets in waterand damages statues and buildings
Solutions to air pollution.• Don’t pollution the air.• Make air pollution laws.• Don’t use spray cans that have CFC’s in them.• Recycle.• Plant trees to take CO2 from the air.• Build less factories.• Electric cars that don’t pollute.
Water pollution: some factories producewastes, which are dumped into the lakes, rivers and oceans.
Solutions to water pollution:• Don’t pollute the water.• Recycle.• Build less factories.• Treat sewage.