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CHAPTER 6: HUMANS IN THE BIOSPHERE 6.1: A CHANGING LANDSCAPE HUMANS IN THE BIOSPHERE IN 1778, EUROPEANS ARRIVED ON THE ISLAND CHAIN OF HAWAII. THEY CHANGED THE ISLANDS BY INTRODUCING RANCHING, PREDATORS, AND DISEASE. LARGE AREAS HAVE BEEN PAVED FOR HOUSING SCHOOLS AND INDUSTRY; NATIVE HAWAIIAN SPECIES ARE GONE EARTH AS AN ISLAND ALL ORGANISMS THAT LIVE ON EARTH SHARE A LIMITED RESOURCE BASE HUMAN POPULATION IS INCREASING; OUR PLANET IS NOT HUMAN ACTIVITIES INDUSTRY AND TECHNOLOGY GIVE HUMANS A STRONG ADVANTAGE IN COMPETING FOR FOOD, ENERGY, AND SPACE HUMANS ARE THE MOST IMPORTANT SOURCE OF ENVIRONMENTAL CHANGE ON THE PLANET FOUR ACTIVITIES THAT HAVE TRANSFORMED THE BIOSPHERE 1. 2. 3. 4. HUNTING AND GATHERING AGRICULTURE INDUSTRY URBAN DEVELOPMENT HUNTING AND GATHERING THIS USED TO BE THE PRIMARY MEANS OF SURVIVAL PEOPLE LIVED IN SMALL GROUPS HUNTING AND GATHERING CAUSED ONE OF THE MAJOR MASS EXTINCTIONS OF LARGE ANIMALS (WOOLY MAMMOTHS, GIANT SLOTHS, AND SABERTOOTH CATS) AGRICULTURE (FARMING) THE SPREAD OF AGRICULTURE WAS IMPORTANT BECAUSE IT PROVIDED PEOPLE WITH A DEPENDABLE SUPPLY OF FOOD HUMANS GATHERED IN LARGER SETTLEMENTS (TOWNS AND CITIES) AND DEVELOPED GOVERNMENT AND LAWS. DOMESTICATION OF ANIMALS (SHEEP, GOATS, COWS, PIGS, HORSES, DOGS) SUPPLIED HUMANS WITH MILK, WOOL, ETC. OVERGRAZING CHANGED GRASSLAND ECOSYSTEMS, ERODED SOIL, AND PUT LARGE DEMANDS ON WATER SUPPLIES TRADITIONAL AGRICULTURE (1450-1700) ALLOWED FOR THE EXCHANGE OF FOODS AROUND THE WORLD TO BEGIN 1800’S: IRRIGATION, NEW CROP VARIETIES, AND FARM MACHINES HELPED FARMERS INCREASE THEIR YIELDS TREMENDOUSLY GREEN REVOLUTION: INTRODUCED NEW FARMING PRACTICES THAT GREATLY INCREASED THE YIELDS OF RICE, WHEAT, ETC. STRATEGIES OF THE GREEN REVOLUTION MONOCULTURE: LARGE FIELDS ARE CLEARED, PLOWED AND PLANTED WITH A SINGLE CROP YEAR AFTER YEAR FARMERS RELY ON IRRIGATION, CHEMICAL FERTILIZERS, AND PESTICIDES THE BENEFIT TO HUMANS FROM THE GREEN REVOLUTION IS NEW FARMING PRACTICES INCREASED FOOD PRODUCTION AND PREVENTED FOOD SHORTAGES PROBLEMS WITH THE GREEN REVOLUTION 1. 2. 3. 4. INTENSIVE FARMING CAN DEPLETE ENERGY AND WATER SUPPLIES MONOCULTURE ALLOWS PESTS TO REPRODUCE QUICKLY PESTICIDES CARRY HARMFUL CHEMICALS FERTILIZERS CAN INTERFERE WITH FOOD WEBS AND BIOGEOCHEMICAL CYCLES INDUSTRIAL GROWTH AND URBAN DEVELOPMENT HUMAN SOCIETY WAS TRANSFORMED BY THE INDUSTRIAL REVOLUTION MOST ENERGY NEEDED TO PRODUCE POWER CAME FROM FOSSIL FUELS (COAL, OIL, NATURAL GAS) INDUSTRIAL PROCESSES POLLUTE AIR, WATER, AND SOIL 6-2: RENEWABLE AND NONRENEWABLE RESOURCES A RESOURCE IS SOMETHING THAT CAN BE USED TO TAKE CARE OF A NEED A COMMON RESOURCE IS AN ENVIRONMENTAL RESOURCE OWNED BY MANY PEOPLE IN COMMON – like the atmosphere or community pool “TRAGEDY OF THE COMMONS”: ANY RESOURCE THAT IS OPEN TO EVERYONE (AIR, OCEANS) WILL EVENTUALLY BE DESTROYED BECAUSE EVERYONE CAN USE IT, BUT NO ONE IS RESPONSIBLE FOR PRESERVING IT NIMBY - _______________________________ TWO TYPES OF ENVIRONMENTAL RESOURCES 1. 2. RENEWABLE: THEY CAN BE REGENERATED AND ARE REPLACEABLE (TREES); THEY CAN BE LIMITED THOUGH NON-RENEWABLE: CANNOT BE REPLENISHED BY NATURAL PROCESSES; ONCE THEY ARE USED, THEY ARE GONE FOREVER (FOSSIL FUELS) SUSTAINABLE USE: A WAY OF USING NATURAL RESOURCES AT A RATE THAT DOES NOT DEPLETE THEM ***UNLESS SUSTAINABLE STRATEGIES ARE USED, HUMAN ACTIVITIES CAN / WILL DAMAGE/DEPLETE RESOURCES LAND RESOURCES IF MANAGED PROPERLY, SOIL IS RENEWABLE. IF NOT, IT WILL BE PERMANENTLY DAMAGED. FERTILE SOIL: BEST FOR FOOD CROPS TO GROW; CONTAINS A MIXTURE OF HUMUS, SAND, CLAY AND ROCK PLOWING: REMOVES ROOTS THAT HOLD SOIL IN PLACE SOIL EROSION = THE WEARING AWAY OF SURFACE SOIL BY WATER AND WIND DESERTIFICATION: COMBINATION OF FARMING, OVERGRAZING AND DROUGHT THAT TURNS PRODUCTIVE AREAS INTO DESERTS OCEAN RESOURCES *VALUABLE FOR FOOD *FISHING HAS INCREASED, BUT FISH STOCKS IN FISHERIES ARE BEING HARVESTED FASTER THAN THEY CAN REPRODUCE=OVERFISHING SUSTAINABLE USE OF FISHERIES LIMIT THE CATCH OF FISH POPULATIONS: THE PROBLEM IS THAT OPEN OCEAN WATERS ARE OUTSIDE THE CONTROL OF ANY ONE SINGLE COUNTRY. AN EXAMPLE OF A COMMON RESOURCE THAT EVERYONE WANTS BUT NO ONE HAS INCENTIVE TO PROPERLY MANAGE – Tragedy of the Commons!! AQUACULTURE: FARMING OF AQUATIC ORGANISMS GOOD BECAUSE IT PRODUCES ANIMAL PROTEIN IF IT ISNT MANAGED, THIS POLLUTES WATER WITH FISH WASTES AIR RESOURCES SMOG: MIXTURE OF CHEMICALS THAT OCCURS AS A GRAY-BROWN HAZE IN THE ATMOSPHERE; IT IS A COMBINATION OF SMOKE AND FOG, MOSTLY DUE TO AUTOMOBILE EXHAUSTS AND INDUSTRY EMISSIONS POLLUTANT: HARMFUL MATERIAL THAT CAN ENTER THE BIOSPHERE THROUGH THE LAND, AIR, OR WATER **BURNING OF FOSSIL FUELS SUCH AS NITRATES, SULFATES, AND PARTICULATES** PARTICULATES: MICROSCOPIC PARTICLES OF ASH AND DUST THAT CAUSE HEALTH PROBLEMS COMBUSTION: RELEASES ACIDIC GASES THAT COMBINE WITH WATER VAPOR, to make NITRIC AND SULFURIC ACIDS -- ACID RAIN. ACID RAIN KILLS PLANTS, CHANGES SOIL CHEMISTRY, AND RELEASES MERCURY FROM THE SOIL WHICH IS TOXIC. WATER RESOURCES OVERALL, WATER IS A RENEWABLE RESOURCE. FRESHWATER IS LIMITED AS A RESOURCE. POLLUTION THREATENS WATER SUPPLIES: WATER POLLUTION!!! OIL SPILLS IMPROPER DISPOSAL OF CHEMICALS LEADS TO THEIR SEEPAGE INTO STREAMS AND RIVERS WASTE DISCARDED ON LAND SEEPS INTO SOIL AND ENTERS GROUNDWATER SUPPLIES DOMESTIC SEWAGE CONTAINS NITROGEN AND PHOSPHORUS COMPOUNDS THAT ENCOURAGES GROWTH OF ALGAE AND BACTERIA IN AQUATIC HABITATS SEWAGE ALSO SPREADS DISEASE AMONG HUMANS AND ANIMALS SUSTAINABLE USE=WATER CONSERVATION 6-3: BIODIVERSITY VARIETY IS ALSO KNOWN AS DIVERSITY. BIODIVERSITY: THE SUM OF THE GENETICALLY BASED VARIETY OF ALL ORGANISMS IN THE BIOSPHERE ECOSYSTEM DIVERSITY: VARIETY OF HABITATS, COMMUNITIES, AND ECOLOGICAL PROCESSES IN THE LIVING WORLD SPECIES DIVERSITY: NUMBER OF DIFFERENT SPECIES IN THE BIOSPHERE GENETIC DIVERSITY: SUM OF ALL DIFFERENT FORMS OF GENETIC INFORMATION CARRIED BY ALL ORGANISMS LIVING ON EARTH BIODIVERSITY IS ONE OF EARTH’S GREATEST NATURAL RESOURCES SPECIES HAVE PROVIDED US WITH: FOODS MEDICINES ANTICANCER DRUGS PAINKILLERS ANTIBIOTICS HEART DRUGS ANTIDEPRESSANTS THREATS TO BIODIVERSITY HUMAN ACTIVITY IS THE NUMBER ONE THREAT! WE ALTER HABITATS, HUNT SPECIES TO EXTINCTION, INTRODUCE TOXIC COMPOUNDS INTO FOOD WEBS, AND INTRODUCE FOREIGN SPECIES TO A NEW ENVIRONMENT EXTINCTION: OCCURS WHEN A SPECIES DISAPPEARS FROM ALL OR PART OF ITS RANGE ENDANGERED SPECIES: SPECIES WHOSE POPULATION SIZE IS DECLINING AND IN DANGER OF EXTINCTION DEMAND FOR WILDLIFE PRODUCTS HUNTING HAS CAUSED EXTINCTION FOR MANY SPECIES TODAY, ENDANGERED SPECIES ARE PROTECTED FROM HUNTING IN THE U.S. AFRICA, SOUTH AMERICA, AND ASIA STILL ALLOW HUNTING OF ANIMALS FOR FOOD, FUR, HIDES, ETC. POLLUTION: SERIOUS PROBLEM THREATENING BIODIVERSITY; OCCURS WHEN TOXIC COMPOUNDS ACCUMULATE IN TISSUES OF ORGANISMS (EX. DDT) 1. DDT WAS THOUGHT TO BE “PERFECT”REMAINS ACTIVE FOR A LONG TIME, KILLS MANY DIFFERENT INSECTS, AND WAS CHEAP 2. WHEN SPRAYED, DRAINED INTO WATER SUPPLIES DDT DDT IS: 1. NON-BIODEGRADABLE: NOT BROKEN DOWN IN NATURE 2. NOT ELIMINATED FROM THE BODIES OF ORGANISMS AS THEY PICK IT UP TWO PROPERTIES THAT MAKES DDT HAZARDOUS DDT IS CONCENTRATED AND STORED IN AQUATIC PLANTS/ALGAEHERBIVORES EAT PLANTS AND GET 10 TIMES THE CONCENTRATION THE PLANTS HADCARNIVORES EAT HERBIVORES AND DDT IS CONCENTRATED EVEN MORE=PROCESS OF BIOLOGICAL MAGNIFICATION BIOLOGICAL MAGNIFICATION: CONCENTRATIONS OF A HARMFUL SUBSTANCE INCREASES IN ORGANISMS AT HIGHER TROPHIC LEVELS IN A FOOD CHAIN/WEB BY THE 1970’S, DDT WAS BANNED IN THE U.S. RACHEL CARSON WROTE A BOOK IN 1962, TITLED “SILENT SPRING” WHICH EXPLAINED THE RESULTS OF USING THE PESTICIDE DDT. INTRODUCED SPECIES INVASIVE SPECIES: PLANTS AND ANIMALS THAT HAVE MIGRATED TO PLACES WHERE THEY ARE NOT NATIVE POPULATIONS EXPLODE BECAUSE THE NEW HABITAT LACKS PARASITES AND PREDATORS 6-4: CHARTING A COURSE FOR THE FUTURE 1. 2. MANY BIOLOGISTS ARE CONCERNED ABOUT THE BIOLOGICAL EFFECTS OF TWO TYPES OF GLOBAL CHANGE: THE THINNING OR DEPLETION OF THE OZONE LAYER GLOBAL WARMING OZONE DEPLETION (O3) OZONE LAYER IS 20-50 KM ABOVE EARTH’S SURFACE OZONE AT GROUND LEVEL IS A POLLUTANT OZONE LAYER ABSORBS UV RADIATION FROM SUNLIGHT BEFORE IT REACHES EARTH’S SURFACE EXPOSURE TO UV RADIATION CAUSES: SUNBURN CANCER DAMAGE TO EYES DECREASED RESISTANCE TO DISEASE *THE OZONE LAYER SERVES AS A GLOBAL SUNSCREEN BECAUSE IT SHIELDS THE BIOSPHERE FROM UV LIGHT 1970’S: “HOLE” DISCOVERED IN OZONE LAYER OVER ANTARCTICA 1995: OZONE HOLE LARGE ENOUGH TO EXPOSE PARTS OF THE US TO HIGH LEVELS OF UV CFC’S: CHLOROFLOUROCARBONS: ACT AS CATALYSTS THAT ENABLE UV LIGHT TO BREAK APART OZONE MOLECULES GLOBAL WARMING GLOBAL WARMING IS AN INCREASE IN THE AVERAGE TEMPERATURE OF THE BIOSPHERE TEMPERATURES BETWEEN 1980 AND 2000 ROSE AT A FASTER RATE THAN DURING THE PREVIOUS 100 YEARS 1990’S WERE THE HOTTEST DECADE EVER RECORDED CAUSES OF GLOBAL WARMING 1. HUMAN ACTIVITIES HAVE ADDED CARBON DIOXIDE AND OTHER GREENHOUSE GASES SUCH AS METHANE TO THE ATMOSPHERE. 2. GLOBAL ATMOSPHERE GREENHOUSE RETAINS MORE HEAT. 3. THE BURNING OF FOSSIL FUELS ADDS CARBON DIOXIDE TO THE ATMOSPHERE, AS DOES CUTTING DOWN AND BURNING FORESTS. 4. NATURAL VARIATIONS IN CLIMATE:AVERAGE GLOBAL SURFACE TEMPERATURE WILL INCREASE BY 1-2 DEGREES CELSIUS BY 2050 IF GLOBAL WARMING CONTINUES AT CURRENT RATES, THE POLAR ICE CAPS WILL CONTINUE TO MELT AND SEA LEVELS COULD RAISE ENOUGH TO FLOOD SOME LOW-LYING COASTAL AREAS STORMS COULD BECOME MORE FREQUENT AND SEVERE MORE SERIOUS DROUGHTS IN NORTH AMERICA ABUNDANCE OF DISEASE CARRYING SPECIES COULD INCREASE HOW DO WE MAINTAIN A HEALTHY BIOSPHERE? USE RESOURCES WISELY RECYCLE MATERIALS CONSERVE ENERGY BETTER INSULATE HOMES AND OFFICES BUY FUEL EFFICIENT CARS *STUDY FOR YOUR TEST!!!