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CHAPTER 6: HUMANS IN THE BIOSPHERE

Bell Ringer

—How do you impact your environment by every day

actions? Write a brief paragraph explaining your impact

on the world, why it is an impact, and whether it is positive

or negative.

—What happens when a growing human population doesn’t

adequately manage natural resources that are both vital

and limited?

The Effect of Human Activity—We affect the environment when we obtain

—Food

—Eliminate waste products

—Build places to live

Effects may not be very large

here, but in islands like Hawaii

with a small surface area, they are

huge!

The Effect of Human Activity● Humans affect regional and global environments

through agriculture, development, and industry

● Huge impact on the quality of Earth’s natural resources (including soil, water, and the atmosphere).

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 on Earth share a limited resource base and depend on it for their long-term survival.

✕ HUMAN POPULATION IS INCREASING; OUR PLANET IS NOT

✕ To protect these resources, we need to

understand how humans interact with the

biosphere.

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

✕What types of human activities can affect the

biosphere?

SOME 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.

✕ What are some of the disadvantages of relying on hunting and gathering to obtain all the food you need?

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.

Agriculture

● Modern agricultural practices have enabled farmers to double world food production over the last 50 years

● Much more food and it can be stored for long periods

● Monoculture: the practice of clearing large areas of land to plant a single highly productive crop year after year

● Ex: Soybeans

Agriculture

● Providing food for 7 billion people, though, puts a strain on natural resources like water and fertilized land

● This is why we invented fertilizers and farm machinery (which also takes a lot of fossil fuel)

✕ 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.

Copyright Pearson Prentice Hall

Agriculture

The Green Revolution

The green revolution was an effort in the mid-

twentieth century to increase global food

production through modern plant breeding

and agricultural techniques.

Over the last 50 years, the green revolution

has helped world food production double.

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

Challenges for the Future

While increasing world food supplies, modern

agriculture has created ecological challenges. For

example:

✕ 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

Industrial Growth● We have a lot of

conveniences now that allow us comfy homes, clothes and electronic devices… but these all require energy to produce and power! ● We get most of this

energy from fossil fuels (coal, oil and natural gas)

● Suburban growth consumes farmland and stresses native plants and animals.

Sustainable Development

● Most ecosystems provide us with “goods and services” like water and air

● If it can’t, then we must spend money in order to produce them● If the water isn’t being

cleaned by the natural rivers and wetlands, we have to pay for chemicals and mechanics to make it safe to drink


● Renewable resource: can be produced or replaced by a healthy ecosystem

● Ex: Water, wind, organisms

● Nonrenewable resource: can’t replenish them within a reasonable amount of time

● Ex: Fossil fuels like coal, oil and natural gas

Using Resources Wisely – 6.2● How do we obtain what we need from our local and

global environments without destroying those environments?

● Not farming is not an option, we all need to eat and depend on things like wheat in many ways!

6-2 Renewable and

Nonrenewable Resources

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


Classifying ResourcesHow are environmental resources classified?

+Environmental goods and services may be

classified as either renewable or

nonrenewable.


Classifying Resources

✕Renewable resources can regenerate if

they are alive, or can be replenished by

biochemical cycles if they are nonliving.

Can be limited though

✕A tree is an example of a renewable

resource because a new tree can be planted

in place of an old tree that dies or is cut

down.


Classifying Resources

✕A nonrenewable resource is one that

cannot be replenished by natural processes.

✕Fossil fuels such as coal, oil, and natural

gas are nonrenewable resources. Once

these fuels are depleted, they are gone

forever.



What effects do human activities have on natural

resources?

+Human activities can affect the quality and

supply of renewable resources such as land,

forests, fisheries, air, and fresh water.

✕ Sustainable development is a way of using

natural resources without depleting them,

and of providing for human needs without

causing long-term environmental harm.

***UNLESS SUSTAINABLE STRATEGIES ARE

USED, HUMAN ACTIVITIES CAN

DAMAGE/DEPLETE RESOURCES


● Sustainable development: using resources in an environmentally conscious and friendly way.

● Provides for human needs while preserving the ecosystem that produces those natural resources

Sustainable Development● It should:

● Cause no long-term harm to the ecosystem

● Consume as little energy and material as possible

● Should be able to withstand environmental stresses (droughts, floods, heat waves, cold snaps)

● Help people improve their situation


Land Resources

✕Land Resources✕Land provides space for human communities and

raw materials for industry. Land also includes the

soils in which crops are grown.

✕If managed properly, soil is a renewable resource.

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 ( material from decayed organisms)

✕ PLOWING: REMOVES ROOTS THAT HOLD SOIL IN PLACE→SOIL EROSION=THE WEARING AWAY OF SURFACE SOIL BY WATER AND WIND

Soil Resources● Healthy soil supports both agriculture and forestry

● Your cereal this morning and the paper of your textbook both depend on soil

Soil Resources

● Topsoil: the mineral and nutrient rich portion of soil● Rich in organic matter

and nutrients

● Allows water to drain

● Produced by long-term interactions between plants

● Can be renewable if managed correctly

Soil Erosion● Soil erosion: the removal of

soil by water or wind● Soil erosion is common

when land is plowed and left barren – all organic materials are carried away

● Desertification: when dry climates, farming, and overgrazing cause a productive area to turn into a desert.

● Caused by farming, overgrazing and drought ● Happened to the Great

Plains in the “Dust Bowl”

Soil Resources● If not managed correctly, topsoil can be depleted and we

lose our farming grounds

● The great “Dust Bowl” in the 1930’s – long drought and bad farming led to a loss of many jobs and fertile land

Forest Resources

✕Forest Resources

✕Earth’s forests are an important

resource for the products they

provide and for the ecological

functions they perform.

Forest Resources

Forest Resources:

✕provide wood for products and fuel.

✕remove carbon dioxide and produce oxygen.

✕store nutrients.

✕provide habitats and food for organisms.

✕moderate climate.

✕limit soil erosion.

✕protect freshwater supplies.

Forest Resources● Some areas can re-grow their forests… but remember succession

(which kind??) takes years!! ● Other areas, like the rainforest, can’t re-grow. Nonrenewable!

✕Whether a forest can be considered a renewable resource

depends partly on the type of forest.

✕Temperate forests of the Northeast are renewable

because they have been logged and have grown back

naturally.

✕Old-growth forests, such as those in Alaska and the Pacific

Northwest, are nonrenewable because it takes centuries to

produce them.


Forest Resources

+Deforestation

✕Loss of forests, or deforestation, has several

effects:

✱Erosion can wash away nutrients in the topsoil.

✱Grazing or plowing can permanently change local soils and

microclimates, which prevents the regrowth of trees.

● Deforestation: the loss of forests● Also has an effect on soil quality because forests hold the soil in place,

protect the quality of the water, absorb carbon dioxide and help the climate.

Soil Erosion● Deforestation can make matters worse if you allow over-

grazing and farming in rainforests

● The topsoil layer in rainforests is very thin, so the organic matter is used up quickly (within a few years)


Forest Resources

+Forest Management

✕Mature trees can be harvested selectively to

promote the growth of younger trees and

preserve the forest ecosystem.

✕Tree geneticists are breeding new, faster-

growing trees that produce high-quality

wood.

Soil Use and Sustainability

● It is possible to minimize soil erosion through careful management of both agriculture and forestry● Leave the stems! Don’t take

everything off● Crop rotation! Change the

type of crop and how often● “Terrace” the land… create

steps to help hold the soil● Selectively harvest trees!

Out with the old, in with the new!

Sustainable development

✕A variety of sustainable-development

practices can prevent problems such as soil

erosion and desertification.

+Sustainable-development practices include:

✕contour plowing—fields are plowed across the slope

of the land to reduce erosion

✕leaving stems and roots of the previous year's crop in

place to help hold the soil

✕planting a field with rye rather than

leaving it unprotected from erosion


Freshwater Resources

✕Freshwater Resources✕Americans use billions of liters of fresh water daily

for everything from drinking and washing to watering

crops and making steel.

✕Although water is a renewable resource, the total

supply of fresh water is limited and is threatened by

pollution.

Freshwater Resources● Remember. Only 3% of Earth’s water is freshwater… and

most of it is frozen in the ice caps!

● We must protect the ecosystems that collect and purify freshwater

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 CONTAINING MICROORGANISMS ALSO SPREADS DISEASE AMONG HUMANS AND ANIMALS

Freshwater Resources● Pollutant: any harmful material that can enter the

biosphere

● Point source pollution: when pollution enters water from one source

● Ex: From a factory or an oil spill

Freshwater Resources● Nonpoint sources: when pollutants enter water supplies

from many smaller sources

● Ex: the grease and oil washed off streets by rain


● The primary sources of water pollution are:

● Industrial and agricultural chemicals

● Residential sewage

Residential Sewage● Where does the waste in your toilet go when it flushes?

● Contaminates water (both fresh and salt) with microorganisms, and depletes it of oxygen



+Sustainable Use of Water

✕One way to ensure the sustainable use of water is to

protect the natural systems involved in the water

cycle that help purify water.

✕These include:

✱wetlands

✱forests

✱other vegetation

✕Also, by conserving water in:✱home

✱industry

✱agriculture

Water Quality and Sustainability

● Watershed conservation: clean all areas, including the areas that drop water off, to prevent pollution● Sewage treatments to eliminate

bacteria and disease

● Use integrated pest management (IPM) – natural predators to the pests instead of pesticides

● Drip irrigation: delivers water drop by drop directly to the roots of the plants that need it

FISHERY RESOURCES✕ Fish and other animals that live in the water

are VALUABLE FOR FOOD

✕ Overfishing, or harvesting fish faster than

they can be replaced by reproduction, has

greatly reduced the amount of fish in parts

of the world’s oceans.

✕ Until recently, fisheries seemed to be a

renewable resource, but overfishing has

limited that resource.


Fishery Resources

+Sustainable Development

✕The U.S. National Marine Fisheries Service has

issued guidelines that specify how many fish, and of

what size, can be caught in various parts of the

oceans.

✕The regulations have helped fish populations

recover.

Fishery Resources

This graph shows how the

cod population has

changed in Georges Bank,

a fishery off the New

England coast. The fish

population began to rise

after regulations restricted

commercial fishing.

http://www.phschool.com/webcodes10/index.cfm?fuseaction=home.gotoWebCode&wcprefix=cbp&wcsuffix=2062


Fishery Resources

This graph shows

how the haddock

population has

changed in Georges

Bank, a fishery off

the New England

coast. The fish

population began to

rise after regulations

restricted commercial

fishing.

http://www.phschool.com/webcodes10/index.cfm?fuseaction=home.gotoWebCode&wcprefix=cbp&wcsuffix=2062

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

Atmospheric Resources

● We need oxygen to breathe! But our pollution is breaking down the ozone layer, which provides us with protection from UV radiation

Atmospheric Resources● Common forms of air pollution include

● Smog

● Acid rain

● Greenhouse gases

● Particulates● Cause respiratory illness (asthma), change

climate patterns and increase skin disease

✕ PARTICULATES: MICROSCOPIC PARTICLES OF ASH AND DUST THAT CAUSE HEALTH PROBLEMS (MOST INDUSTRIES USE TECHNOLOGY TO CONTROL EMISSIONS)

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 ANDINDUSTRY EMISSIONS

Considered a pollutant because it threatens peoples health


Air Resources✕A pollutant is a harmful material that can

enter the biosphere through the land, air,

or water.

✕The burning of fossil fuels can release

pollutants that cause smog and other

problems in the atmosphere.

Strict automobile emissions standards and

clean-air regulations have improved air

quality in many cities, but air pollution is

still a problem.

Air Resources

✕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 by damaging their leaves and

changing the chemistry of soils and standing-water

ecosystems.

✕Acid rain may dissolve and releases toxic elements,

such as mercury, from the soil, freeing the

elements to enter other portions of the biosphere.


✕Formation of Acid Rain

✕ Acid rain results from the chemical transformation of nitrogen and

sulfur products that come from human activities.

Air Resources

Emissions to AtmosphereNitrogen oxides

Sulfur dioxide

Chemical TransformationNitric acid

Sulfuric acid

Condensation

Dry FalloutParticulates

Gases

PrecipitationAcid rain, fog, snow,

and mist

Industry Transportation Ore smelting Power

generation

6-3: BIODIVERSITY

✕ VARIETY IS ALSO KNOWN AS DIVERSITY.

✕ BIODIVERSITY: THE SUM TOTAL 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 TOTAL OF ALL DIFFERENT FORMS OF GENETIC INFORMATION CARRIED BY ALL ORGANISMS LIVING ON EARTH

http://www.youtube.com/watch?v=GK_vRtHJZu4

Why is biodiversity importnant?

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

What are current 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

✕ As the population of an endangered species

declines, the species loses genetic diversity.

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

✕Demand for Wildlife Products✕Throughout history, humans have pushed some

animal species to extinction by hunting them for

food or other products.

✕Today, in the U.S., endangered species are

protected from hunting.

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.

✕ The Convention on International Trade in Endangered Species, CITES, bans international trade in products derived from endangered species.

✕ 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

✕ ONE OF THE MOST SERIOUS OCCURS WHEN TOXIC COMPOUNDS ACCUMULATE IN TISSUES OF ORGANISMS (EX. DDT)

1. DDT WAS THOUGHT TO BE “HARMLESS”-REMAINS ACTIVE FOR A LONG TIME, KILLS MANY DIFFERENT INSECTS, AND WAS CHEAP

2. WHEN SPRAYED, DRAINED INTO WATER SUPPLIES

Industrial and Agricultural Chemicals✕When DDT enters food webs, it undergoes

biological magnfication.

✕In biological magnification, concentrations of a

harmful substance increase in organisms at higher trophic levels in a food chain or food web. When a pollutant (like DDT or mercury) is picked up by an organism and is not broken down or eliminated from its body● Concentration increases as it goes up the food chain

Industrial and Agricultural Chemicals

● The concentration of DDT was so high at one point that it threatened the existence of our national bird – the Bald Eagle

Industrial and Agricultural Chemicals

● Industrial pollutants are difficult to eliminate because they stay underneath the ground, in the sand and mud

● Ex: PCB’s – these were banned in the 1970’s

● Ex: DDT, a pesticide and insecticide that ran off into water supply

TWO PROPERTIES THAT MAKES DDT

HAZARDOUS

1. 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

✕ 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 alerted people to the dangers of biological magnification and EXPLAINED THE RESULTS OF USING THE PESTICIDE DDT.


PollutionMagnification of

DDT Concentration

http://www.youtube.com/watch?v=Ipbc-6IvMQI

http://www.youtube.com/watch?v=L8149TO0EU0

http://www.youtube.com/watch?v=vbtp2B-IFmw


Introduced Species

✕Introduced Species✕Another threat to biodiversity comes from plants

and animals that humans transport around the world

either accidentally or intentionally.

✕Invasive species are introduced species that

reproduce rapidly because their new habitat lacks

the predators that would control their population.

CONSERVING BIODIVERSITY✕ CONSERVATION: WISE MANAGEMENT OF NATURAL

RESOURCES LIKE THE PRESERVATION OF HABITATS AND WILDLIFE

✕ Strategies for Conservation

Many conservation efforts are aimed at managing individual species to keep them from becoming extinct.

✕ 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

Conserving

Biodiversity

What is the goal of conservation biology?

+Conservation efforts focus on protecting entire ecosystems as well as single species.

+Protecting an ecosystem will ensure that the natural habitats and the interactions of many different species are preserved at the same time.

Conserving BiodiversityConservation Challenges

✕Protecting resources for the future can require

people to change the way they earn their living

today.

✕Conservation regulations must be informed by solid

research and must try to maximize benefits while

minimizing economic costs.

✕ 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

http://www.youtube.com/watch?v=RaQBaVeEbW8

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 CLIMATE SYSTEM

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

✕ damage plant leaf tissue and phytoplankton

in the oceans

*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

Ozone Depletion

One Solution

CFCs (chlorofluorocarbons) were once

widely used:

✱as propellants in aerosol cans

✱as coolant in refrigerators,

freezers, and air conditioners

✱in the production of plastic foams

The U.S. and other nations began

reducing the use of CFCs in 1987, and

eventually banned them.


Ozone Depletion

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

✕ One sign of global warming is melting of

polar ice

✕ 1990’S WERE THE HOTTEST DECADE EVER

RECORDED

Global Climate Change

Biologists are concerned

about global warming. This

map of the Arctic is based on

images taken by satellites in

1979 and 1999. Sea ice in

the Arctic Ocean has receded

so quickly that some

scientists suggest that, within

the next 50 years, the ice

could disappear completely.

Global Climate Change

Evidence of Global Warming

The geological record shows that Earth’s climate has

changed repeatedly during its history.

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

THE VALUE OF A HEALTHY BIOSPHERE

✕ A HEALTHY BIOSPHERE PROVIDES US WITH

VALUABLE GOODS AND SERVICES:

+ TEMPERATURE CONTROL

+ WATER PURIFICATION

+ SOIL FORMATION

The Value of a Healthy

Biosphere

Human

society

depends on

healthy,

diverse, and

productive

ecosystems

because of the

environmental

and economic

benefits they

provide.

HOW DO WE MAINTAIN A HEALTHY

BIOSPHERE?

✕ USE RESOURCES WISELY

✕ RECYCLE MATERIALS

✕ CONSERVE ENERGY

✕ BETTER INSULATE HOMES AND OFFICES

✕ BUY FUEL EFFICIENT CARS

Meeting Ecological Challenges

● Ecological Footprint: describes the total area of functioning land and water ecosystems needed to provide resources for an individual/population and to absorb harmless wastes from that individual/population

Meeting Ecological Challenges● Ecological footprints help us determine what the carrying

capacity is for humans and our own impact on the world

● No exact way to calculate it

● It is estimated that Americans footprints are four times larger than the global average – we use too much!!

Meeting Ecological Challenges● Steps to take action:

● 1. Recognize the problem in the environment

● 2. Research the problem to determine its cause

● 3. Use scientific understanding to change our behavior to have a positive impact on the global environment

Let’s Meet A Challenge!● In your table groups, design an ecologically sustainable

house and draw it out on a piece of paper. You will have to explain the different things you’ve added to the house that make it sustainable.

http://www.youtube.com/watch?v=5eTCZ9L834s

chapter 6: humans in the biosphere - ms. …mgaughan-biology.weebly.com/uploads/1/1/0/3/... · bell...

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