Understanding Human Impact on Earth's Resources

1. Chapter 6 Humans in the Biosphere

2. A Changing Landscape “Earth is an Island” • All organisms- including humans -that live on Earth share limited resources & depend of them for their survival. • Natural ecological processes sustain these resources (water, carbon, nitrogen cycles) • To protect these resources – we must understand how humans interact with the Earth

3. Humans and the Biosphere • We as humans depend on chemical cycles (H20, C, N) to provide: a. breathable air b. drinkable water c. fertile soil d. storage & recycling of nutrients • We must understand how human activity affects these cycles

4. Human Activities that Affect the Biosphere • Hunting & gathering • Agriculture • Industry • Urban development • Human activity has become the most important source of environmental change on the planet. • We do not fully understand how these activities affect our ecosystems

5. Industrial growth Urban development Hunting and gathering Agriculture Green revolution Extinctions of large animals Increased pollution High standard of living Monoculture use Food supply Pesticide use Human Activities that have changed the biosphere include may have once caused often relies on the methods of the have resulted in which increased

6. Renewable Resources • Can regenerate or can be replenished • Not always unlimited • Example: - Water can become limited by drought or overuse • Human activity can affect the quality of renewable resources such as: - land, forests, fisheries, air & freshwater

7. Nonrenewable Resource • Cannot be replenished by natural processes • When they are depleted – they are gone forever • Example: - coal - oil - natural gas (fossil fuels)

8. Sustainable Development • Way of using natural resources without depleting them • Provides humans with what they need without causing long term environmental harm • This can have a positive impact on the environment we create for ourselves & future generations

9. Biodiversity • The sum of the genetically based variety of all organisms in the biosphere • Basically, how all living things are so different!!! • Greatest natural resource • The many different species provides us with: 1. food 2. industrial products 3. medicines (painkillers, antibiotics, heart, antidepressants & anticancer drugs) • When biodiversity is lost, potential sources of material with significant value to Earth & mankind may be lost with it

10. Types of Diversity • Ecosystem Diversity: • Variety of habitats, communities, and ecological processes in the living world • Examples: habitats ecological processes 1. deserts 1. water cycle 2. mountains 2. carbon cycle 3. rain forests 3. nitrogen cycle 4. oceans 4. phosphorus cycle

11. Types of Diversity • Species Diversity • Refers to the # of different species in the biosphere • Scientists have identified & named about 1.5 million species • They estimate millions will still be discovered • Genetic Diversity • Refers to the total of all the different forms of genetic information carried by all organisms living on Earth today (DNA)

12. Threats to Biodiversity • Altering habitats • Hunting to extinction • Introducing toxic compounds into food webs • Introducing foreign species to new environments