Humans in the Biosphere (Chapter 6) Please set up your notebook for Cornell Notes

Human activities that impact the biosphere Hunting and gathering Hunt animals for food, gathered plant matter The arrival of humans in North America 12,000 years ago caused the extinction of many large mammals

Agriculture  farming Provided a dependent source of food Lead to the development of larger communities Advances in techniques lead to crops being grown in new areas Monoculture  large fields planted w/ one type of plant Chemical fertilizers and pesticides are used to increase yield The chemicals can run off and affect water supplies Green revolution  evolution of modern techniques that increased world’s food supply How can we keep humans fed w/ less impact on the planet?

Industrial growth and urban development Increase in pollution and waste What do we do with all of our trash? How can we limit pollution?

Biodiversity Biodiversity  the variety of all life on the planet Ecosystem biodiversity  all the habitats, communities and ecological processes in the world Species Diversity  the number of different species in the biosphere Also called species richness Highest near the equator, lowest near the poles All organisms in the biosphere are linked

Threats to biodiversity Human activity can reduce biodiversity by altering habitats, hunting species to extinction, polluting and introducing foreign species into the environment Some of these activities lead to extinction Species that are at risk of going extinct are considered endangered Foreign species that reproduce quickly and threaten native species are called invasive species Conservation  wise use of natural resources, including preserving habitats and wildlife

Global Climate Change Gases in atmosphere help trap heat from the sun much like a green house  called green house effect Necessary for life Evidence of global warming Geological record shows Earth’s climate has changed repeatedly in history How have how human activities contributed to climate change? Increasing levels of CO 2 in the atmosphere Possible effects of global climate change Increase in average global temperature 1-2 C Could cause flooding of coastal areas as ice caps melt Increases in extreme weather Drought, snow, hurricanes Extinction of organisms that cannot adapt to new, higher temps.