1. Humans in the Biosphere

2. Changing the landscape  Humans depend on and participate in food webs and chemical cycles.  Activities that affect the biosphere –Hunting and gathering –Agriculture –Industry –Urban development 6-1

3. Hunting and Gathering  Our ancestors obtained food by hunting and gathering  They hunted for birds and mammals, and fished in rivers and oceans  They also gathered seed, fruits and nuts  These activities changed the environment.

4. Agriculture  Agriculture = farming –One of the most important developments in human history  Why?  Monoculture is when a large field is used to plant one type of plant year after year

5. The Green Revolution  The introduction of monoculture and the use of chemical fertilizers became know as the green revolution  This is because it greatly increase the worlds food production.

6. Challenges for the Future  Large scale monoculture lead to problems with pests and diseases –Chemical pesticides can damage beneficial insect, contaminate water and accumulate in the environment  Finding enough water for irrigation also became a problem

7. Industrial growth and urban development  These have provided us with many of the modern conveniences such as homes, clothes, electronics, machines cars, etc.  The down side is the pollution put in the air, water, and land due to this  Also human growth takes up natural habitats that puts stress on plants and animals ability to survive.

8. Classifying Resources EEEEnvironmental goods and services may be classified as either renewable or nonrenewable. 6-2

9. Renewable resources  Resources that can regenerate if they are alive or can be replenished by biochemical cycles if they are nonliving.  Example – a tree can grow in place of an old tree that dies or is cut down

10. Nonrenewable resource  A resource that cannot be replenished by natural processes.  Example – fossil fuels (coal, oil, and natural gas) formed over hundreds of millions of years from deeply buried organic materials, when they’re gone they’re gone forever.

11. Classifying a resource renewable or nonrenewable  This depends on the context, a single tree is renewable, a population of trees in a forest ecosystem may not be renewable.  If a community of organisms depends on the trees, the ecosystem may change forever once those trees are gone

12. Land Resources  Land is important b/c it gives us space to live on and materials for industry.  It also includes soil which crops are grown in  Soil is renewable if managed properly, but can be permanently damaged if mismanaged

13.  Soil erosion is the wearing away of surface soil by water and wind –Plowing the land removes roots and plants which hold soil in place  A combination of farming, overgrazing, and drought has turned productive areas in to deserts –this is known as desertification

14. Forest Resources  Forests are important for the products they provide and for the ecological functions they perform  Loss of forest, deforestation, leads to soil erosion which washes away nutrients

15. Fish Resources  Fish and other animals that live in water are valuable sources of food for humanity  Overfishing means we are taking fish out of the water faster than they are reproducing –Fish populations are decreasing because of this

16.  Sustainable development is a way to try and maintain the worlds fish supply  There are guidelines/rules which tell fishermen how many and what size fish they can catch  Aquaculture, the raising of aquatic animals for human consumption, is helping to sustain fish resources

17. Air resources  Air is a common resource that we use every time we breathe, the condition of the air affects people’s health  Smog- a mixture of chemicals that occurs as a gray-brown haze in the atmosphere.  Smog is a pollutant, it is a harmful material that can enter the biosphere through the land, air or water.

19. Causes of air pollution  The burning of fossil fuels can release pollutants into the atmosphere  Burning fossil fuels releases sulfur and nitrogen compounds into the air  Acid rain is caused by these substances combining with water vapor

21. Biodiversity  Biodiversity = total of the genetically based variety of all organisms in the biosphere  Bio = lifeDiversity = variety  Biodiversity is the earths greatest natural resource  Species of many kinds have provided us with foods, industrial products and medicines – such as painkillers, antibiotics, heart drugs, antidepressants, and anticancer drugs 6-3

22. Threats to biodiversity  Human activities can reduce biodiversity –Altering (changing) habitats –Hunting species to extinction –Introducing toxic compounds into food webs –Introducing foreign species to new environments

23. Habitat alteration  When humans develop land habitants are destroyed  As habitats disappear, the species that live there disappear.  When a habitat is split into pieces by development it is called habitat fragmentation.

26. Pollution  Humans add many toxic chemicals into the environment that threaten biodiversity  Biological magnification – concentrations of toxins increase in organisms at higher trophic levels in a food chain or web  Each step up in the food chain magnifies the toxin

29. Introduced Species  Plants and animals that seem harmless are transported around the world by humans.  These organisms can end up altering native communities.

30. Invasive Species SSSSpecies that are introduced into new habitats and reproduce rapidly. TTTThis happens because their new habitat lacks the parasites and predators that normally control their population “back home”.

31. Conservation  Conservation – the wise management of natural resources, including preserving of habitat and wildlife.  Conservation focuses on protecting ecosystems, which will ensure that the natural habitat and the interactions of many different species are preserved at the same time

32. Ozone depletion  Ozone layer protects the Earth from the Sun’s Ultra-violet radiation  Ozone layer has been broken down by pollutants put in the air by humans, mainly cfc’s 6-4

33. Results of Ozone Depletion  Ultra-violet radiation causes cancer –Skin cancer in humans has increase over the last 20 years.  Global warming = the average temperature of earth’s surface is rising

34. Effects of Global Warming  Higher temperatures  Sea levels may rise  Ecosystems could change

35. Value of a Healthy Biosphere  The environment provides both environmental and economic benefits to humans  Such as -Insects that pollinate our crops -Organisms that provide us with new medicine - new varieties of crops

36. How can we help  Avoid using excess water (showering, watering plants)  Plant trees to replace ones cut down  Reuse/recycle trash and other wastes  Dispose chemicals in ways that don’t harm ecosystems  Cut down on use of fossil fuels