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
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)
PEOPLE STILL FOLLOW THIS WAY OF LIFE AND
SUPPLEMENT THEIR DIET WITH THE MEAT OF WILD
ANIMALS: SUBSISTENCE HUNTING
SUBSISTENCE HUNTING ALLOWS THE USE OF GUNS,
SNOWMOBILES, TOOLS, ETC.
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: GOVERNMENTS AND
SCIENTISTS INTRODUCED NEW, INTENSIVE
FARMING PRACTICES THAT GREATLY
INCREASED THE YIELDS OF RICE, WHEAT,
ETC.

STRATEGIES OF THE GREEN REVOLUTION




DEVELOPMENT OF NEW, HIGHLY PRODUCTIVE
VARIETIES OF MAJOR FOOD CROPS=MIRACLE
STRAINS
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
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)
 URBAN CENTERS BECAME CROWDED AND
PEOPLE MOVED FROM CITIES TO SUBURBS
 INDUSTRIAL PROCESSES POLLUTE AIR, WATER,
AND SOIL
READ 6-1 IN YOUR BOOK AND COMPLETE YOUR
GUIDED READING WORKSHEETS!!!

6-2: RENEWABLE AND NONRENEWABLE
RESOURCES
A RESOURCE IS SOMETHING THAT CAN BE
DRAWN UPON TO TAKE CARE OF A NEED
 A COMMON RESOURCE IS AN ENVIRONMENTAL
RESOURCE OWNED BY MANY PEOPLE IN
COMMON
 “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

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 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
 HUMUS IS MOSTLY TOPSOIL THAT ABSORBS AND
RETAINS NUTRIENTS
 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
SUSTAINABLE USE PRACTICES
1.
2.
CONTOUR PLOWING: FIELDS ARE PLOWED
ACROSS THE SLOPE OF THE LAND TO
REDUCE EROSION
LEAVE THE STEMS AND ROOTS IN PLACE TO
HELP HOLD SOIL
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
 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 (MOST
INDUSTRIES USE TECHNOLOGY TO CONTROL
EMISSIONS)
COMBUSTION: RELEASES ACIDIC GASES CONTAINING
NITROGEN AND SULFUR COMPOUNDS INTO THE
ATMOSPHERE. WHEN THEY COMBINE WITH WATER
VAPOR, NITRIC AND SULFURIC ACIDS ARE FORMED
AND FALL TO EARTH’S SURFACE AS 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:





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
READ SECTION 6-2 IN YOUR BOOKS AND
MAKE SURE GUIDED READING
WORKSHEETS ARE COMPLETE FOR THIS
SECTION!!!
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

HABITAT ALTERATION AND FRAGMENTATION
WHEN LAND IS DEVELOPED, NATURAL HABITATS
ARE DESTROYED. SPECIES VANISH AS A RESULT.
 HABITAT FRAGMENTATION: LAND DEVELOPMENT
SPLITS ECOSYSTEMS INTO PIECES; THESE PIECES
BECOME “BIOLOGICAL ISLANDS”ANY PATCH
OF HABITAT SURROUNDED BY A DIFFERENT
HABITAT
*THE SMALLER THE ISLAND, FEWER SPECIES
CAN LIVE THERE, RESULTING IN SMALLER
POPULATIONS*

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.
 CITES=CONVENTION ON INTERNATIONAL TRADE
IN ENDANGERED SPECIES; IT BANS TRADE IN
PRODUCTS DERIVED FROM AN AGREED UPON
LIST OF ENDANGERED SPECIES

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

TWO PROPERTIES THAT MAKES DDT
HAZARDOUS
NON-BIODEGRADABLE: NOT BROKEN DOWN IN
NATURE
2. NOT ELIMINATED FROM THE BODIES OF
ORGANISMS AS THEY PICK IT UP
DDT IS CONCENTRATED AND STORED IN AQUATIC
PLANTS/ALGAEHERBIVORES EAT PLANTS AND
GET 10 TIMES THE CONCENTRATION THE
PLANTS HADCARNIVORES EAT HERBIVORES
AND DDT IS CONCENTRATED EVEN
MORE=PROCESS OF BIOLOGICAL
MAGNIFICATION
1.
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; INCREASE THE
POPULATIONS BECAUSE THE NEW HABITAT
LACKS PARASITES AND PREDATORS THAT
CONTROL THE POPULATION “BACK HOME”
CONSERVING BIODIVERSITY
CONSERVATION: WISE MANAGEMENT OF
NATURAL RESOURCES LIKE THE PRESERVATION
OF HABITATS AND WILDLIFE
 STRATEGIES FOR CONSERVATION:
1. CAPTIVE BREEDING PROGRAMS
2. FOCUS ON PROTECTING ENTIRE ECOSYSTEMS
AS WELL AS SINGLE SPECIES
3. GOVERNMENT SETS ASIDE LAND, EXPANDS
EXISTING AREAS AS PARKS/RESERVES
4. MARINE SANCTUARIES

CHALLENGES IN CONSERVATION
THE NEED TO PROTECT BIODIVERSITY IS
GREATEST IN COUNTRIES LEAST ABLE TO DO SO
 RAINFOREST DESTRUCTION IS THE GREATEST
THREAT TO BIODIVERSITY ON LAND
 CONSERVATION BIOLOGISTS IDENTIFY “HOT
SPOTS” WHERE SIGNIFICANT NUMBERS OF
HABITATS AND SPECIES ARE IN DANGER OF
EXTINCTION
READ 6-3 IN YOUR TEXTBOOK AND COMPLETE
GUIDED READING WORKSHEETS FOR THIS
SECTION!!!

6-4: CHARTING A COURSE FOR THE FUTURE
MANY BIOLOGISTS ARE CONCERNED ABOUT
THE BIOLOGICAL EFFECTS OF TWO TYPES OF
GLOBAL CHANGE:
1. THE THINNING OR DEPLETION OF THE
OZONE LAYER
2. 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.
2.
3.
4.
HUMAN ACTIVITIES HAVE ADDED CARBON
DIOXIDE AND OTHER GREENHOUSE GASES
SUCH AS METHANE TO THE ATMOSPHERE.
GLOBAL ATMOSPHERE GREENHOUSE RETAINS
MORE HEAT.
THE BURNING OF FOSSIL FUELS ADDS CARBON
DIOXIDE TO THE ATMOSPHERE, AS DOES
CUTTING DOWN AND BURNING FORESTS.
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

THE VALUE OF A HEALTHY BIOSPHERE

A HEALTHY BIOSPHERE PROVIDES US WITH
VALUABLE GOODS AND SERVICES:
 TEMPERATURE
CONTROL
 WATER PURIFICATION
 SOIL FORMATION
HOW DO WE MAINTAIN A HEALTHY BIOSPHERE?
USE RESOURCES WISELY
 RECYCLE MATERIALS
 CONSERVE ENERGY
 BETTER INSULATE HOMES AND OFFICES
 BUY FUEL EFFICIENT CARS

*READ 6-4 IN YOUR BOOK AND COMPLETE
GUIDED READING WORKSHEETS.
*STUDY FOR YOUR TEST!!!