Human Impacts on the Environment and the 3Rs

7SCIENCE: Mon. Feb. 21

Review: We have learned some ways that humans make an impact on the environment

• Population growth• Pollution:– Air pollution– Water pollution

• Today we will learn a few more effects humans have on the environment:– Farming and grazing– Deforestation– Landfills– Natural preserves

Farming and Grazing• Land is as important to people as clean air and

water:• Farming (agriculture)– Land is used to produce food for humans– Chemicals such as pesticides, herbicides and

fertilizers are used to increase productivity• Grazing – Land is also used to raise animals for human

consumption (e.g. cows = milk, meat)– Usually land that cannot be used for

farming

Deforestation

• Some land is used as a source of wood• Deforestation:– Trees are cut down for paper, fuel, or as

a building material– Trees SHOULD BE replanted, however

many forests in tropical regions are not being replaced

• Some studies suggest that up to 50 000 species could become extinct because they are losing their habitat (forest)

Landfills

• Land is also used for storing wastes from humans

• Landfill– Area where waste is

deposited

• Sanitary landfill is covered with dirt and this prevents waste from blowing away and reduces the odor (smell)– These landfills are lined with materials to prevent

liquid waste from going into the water and soil

Natural Preserves

• A natural preserve is land that is not used by humans to produce something or to store waste– E.g. forests, national parks i.e. Parque Tayrona

• Land in its natural state is decreasing as human population increases

• WHY?

Introduction to the 3Rs

• The 3Rs represent the ideas to:– Recycle– Reduce– Reuse

• These 3 ideas can help to decrease the human impact on the environment

• How? Think of ways that the 3Rs can be applied to a human impact we learned about today in class