humans impact environment

8/12/2019 Humans Impact Environment

1/54

Humans and The Environment


2/54

HumanActivities

that have changed the biosphere include

may have once caused often relies on the methods of thehave resulted in

which increased

Food supply Pesticide use Monocultureuse

Hunting andgathering

AgricultureIndustrial

growthUrban

development

Extinctions oflarge animals

Greenrevolution

High standardof living

Increasedpollution

Section 6-1

Concept Map

Go toSection:


3/54

Leaving a Mark on the World

Have you ever seen very old photographs of

the town or city in which you now live? Has

your area changed? Perhaps there are morebuildings or roads than there were many

years ago. Maybe your town or city has more

trees and flowers now than it had years ago.

Humans, like all organisms, have an effect ontheir environment.

Section 6-1

Interest Grabber

Go toSection:
http://localhost/var/www/apps/conversion/tmp/Biology%20Main%20Menu.ppt


4/54

Earth is a kind of island

Limited resources

Nature must sustain the resources Human populations is growing

The planet is not


5/54

Demands on

Air

Water

Land

Living things


6/54

We must protect these resources

What human activities do you think have an

impact on the earths natural resources?

Hunting and gathering

Agriculture

Industry

Urban development


7/54

Recent study concluded that human activity uses

as much energy as all of earths other

multicellular species combined

Humans are the most influential in changing the

environments of the planet


8/54


9/54

Early man

Built dams

burned grasslands to encourage growth of certain

plants


10/54


11/54

Agriculture

Early humans learned how plants grew, which

were edible, and which were good medicines

They began to plant those that were important

near their settlements

11,000 years ago, humans started farming

(Agriculture)


12/54

Agriculture

Agriculture spread

With dependable food supply, people started

living in larger settlementstowns and cities

Domestication of Animals

Over time, people started keeping herds of

domesticated animals


13/54


14/54

Agriculture

Milk, meat, hides, wool, companionship, perform

work

Overgrazing changed grasslands ecosystems

eroded soils, large demand on water

Human population grew at an increasing rate.


15/54

Green Revolution

By 1950s food supply was straining

Green Revolutionto increase food supply,

governments and scientists introduced new

farming techniques to increase yields of crops

(rice, wheat, corn)

Relied on new, highly productive strains of crops


16/54

Green Revolution

Monoculturelarge fields plowed, and planted

with a single crop year after year

Irrigation, fertilization, and pesticides were relied

on to sustain the crops

Animal and human power was replaced with

machine power

Within 20 years, Mexican farmers increasedproduction of wheat 10 times


17/54

Green Revolution

Problems have been introduced by the green

revolution. Can you name a few?

Depletion of water supplies

Pollution of water by pesticides and fertilizers


18/54

Industrial growth and Urban

Development

Wastes from manufacturing and energy

production have been poured into the air, water,

and soil

Tied to high standard of living that we all enjoy


19/54

The question is: How do we control the harmful

effects of human activity on the environment?


20/54

Tragedy of the Commons

Resource is something that can be used to take

care of a need

When an environmental resource is owned by

many people, or no one, but no one isresponsible for it, it is called a common

resource.


21/54

Tragedy of the Commons

The Tragedy of the Commonsany resource

open to everyone will eventually be destroyed

because although everyone owns the resource,

no one is responsible for it. Air, Watershared by many countries, but no

one is responsible.


22/54

Whalingif some countries attempt to protect

whales, but others continue to hunt whales to

extinction, what will eventually happen?


23/54

2 types of resources Renewable and Nonrenewable

Renewable resources can be regenerated (but

not necessarily limitless)

Sunlight

Fresh water

A tree

Fish


24/54

2 types of resources Renewable and Nonrenewable

Nonrenewablecannot be replenished by

natural resources

Fossil fuels

Coal

Oil


25/54

1. Examine the list of natural resources shown below. Then,

classify each natural resource as either renewable or

nonrenewable.

a. Wood

b. Fossil fuels

c. Aluminum

d. Wool

e. Gold

2. Describe the impact that the loss of nonrenewable

resources would have on the environment.

Section 6-2

Interest Grabber continued

Go toSection:


26/54

Where Do NaturalResources Come From?

Natural resources are materials that are supplied

by nature. A renewable resource is one that isreplaceable. A nonrenewable resource is one that

cannot be replenished by natural processes.

Once a nonrenewable resource is used up, it is

gone forever.

Section 6-2

Interest Grabber

Go toSection:


27/54

Land Resources

Land is a resource

Provides space for living, raw materials for

building, and industry

Important for soils crops grow on


28/54

Land Resources

Soil is a renewable resource that can be

damaged by human activities

Best fertile soil is a mixture of humus, sand, clay,

and rock particles


29/54

Most of the humus is in the top layers called

Topsoil

Absorbs and retains moisture, but allows drainage

Lots of nutrients

Low in salts


30/54

Different plants add and use different amounts ofnutrients

Plowing the land removes the roots that prevent

erosion Erosionthe wearing away of the surface soil by

water and wind

Combinations of farming, overgrazing, and

drought can cause productive areas to becomedeserts

Process is desertification


31/54

Practices that can maintain the soil include

Contour plowing

Planting crops that maintain the soil while primary

crops are harvestedrye for example Leaving roots and stems of previous years crops


32/54

Cover Crops

Legumes, grasses, and other

cover crops recycle soil nutrients,reduce fertilizer need, and

prevent weed growth.

Controlled Grazing

By managing graze periods and herd

densities, farmers can improve nutrientcycling, increase the effectiveness of

precipitation, and increase the carrying

capacity of pastures.

Biological Pest Control

The use of predators and parasites

to control destructive insectsminimizes pesticide use as well as

crop damage

Contour Plowing

Contour plowing reduces

soil erosion from land runoff.

On hilly areas, plowing is doneacross the hill rather than

straight up and down.

Crop Rotation

Different crops use and

replenish different nutrients.

By rotating crops, the lossof important plant nutrients

is decreased.

A B C

Yr. 1

Yr. 2

Yr. 3

Section 6-4

Sustainable Agriculture

Go toSection:

corn

corn

corn

alfalfa

alfalfa

alfalfa

oats

oats

alfalfa(plowed in)


33/54

Forest Resources

Forests provide

Wood

Paper

Fuel

Remove CO2 and add O2

Food

Sore nutrients

Moderate climate

Limit soil erosion

Protect fresh water supplies


34/54

Forest Resources

DeforestationLoss of forests

Soil erosiontopsoil and nutrients washed away

Grazing and plowing after deforestation can add

to problems

Sustainable use strategies

Harvesting mature trees selectively

Plant, manage, harvest, and replant tree farms

Geneticists breeding faster growing varieties


35/54

Ocean Resources

Food

Fish catch has risen from 20 million tons/year to

over 90 million tons / year

As fish catches rose, fish stocks declined

Overfishing

Techniques to moderate include

Limits

Aquaculture

Temporary closing of areas to fishing


36/54

World Fish Catch World Fish Catch per Person

TotalCatch

(milliontons

)

AmountofFishpe

rPerson

(kilograms

)

Year Year

Section 6-2

Growth of Fish Catch

Go toSection:


37/54

Air Resources

Air is a resourcewe breath it

Smogsmoke and fog

Auto and industrial exhaust include Nitrogen oxides andsulfur dioxides that are transformed into nitric and sulfuricacids

Cause acid rain

Pollutanta harmful material that can enter the biospherethrough land, air, or water

Acid rain can kill plants, and cause soil chemistry tochange

May release Hg, or other dissolved toxic elements

Figure 6 12 The Formation of


38/54

Emissions to Atmosphere

Nitrogen oxides

Sulfur dioxide

Chemical Transformation

Nitric acid

Sulfuric acid

Precipitation

Acid rain, fog,

snow, and mist

Dry Fallout

Condensation

particulates, gases

Industry Transportation Ore smelting Power generation

Section 6-2

Figure 6-12 The Formation ofAcid Rain

Go toSection:


39/54

Water Resources

Water is a resource

Drinking, washing, watering crops, industry

71% of the earth is covered by water

97% of the water is sea water (salty)

2% more is frozen

1% of all water is liquid fresh water


40/54

Pollution

Wastes discarded (on purpose or not) can

Seep into water supplies

Sewage

Contains nitrogen and phosphorus

Cause algal and bacterial growth

Spread disease


41/54

Pollution

Wetlands such as swamps and estuaries can

help to protect water supplies

Purifies water as it passes through

Holds soil in place

What Is


42/54

What Is

Biodiversity?

Biodiversity is the sum total of the variety of

organisms in the biosphere. Sometimes humanscan reduce biodiversity, which is considered a

natural resource.

Interest Grabber

Go toSection:


43/54

Biodiversity

1.5 million species identified so far

Food

medicinepainkillers, heart drugs, antibiotics

industrial products


44/54

Insects

BacteriaFungi

Plants

Protists Other Animals

54.4%

4.2%

18%

3.4%0.3%

19.7%

Section 6-3

Species Diversity

Go to

Section:


45/54

Biodiversity

Human activity can reduce biodiversity

May cause extinction


46/54

Figure 6-16 Biological


47/54

Fish-Eating BirdsMagnification of

DDT Concentration

10,000,000

100,000

10,000

1,000,000

1

1000

LargeFish

Small Fish

Zooplankton

Producers

Water

Section 6-3

Figure 6 16 BiologicalMagnification of DDT

Go to

Section:


48/54

Biological magnification

Concentrates as herbivores eat plants sprayed

with DDT, then carnivores eat the herbivores

etc


49/54

Introduced species

Organisms transferred from one area to another

that did not have them before

Zebra Mussel, Phragmites, Japanese shore crab

I t t G bb ti d


50/54

1. Choose an animal other than a humanand describe at least two ways in which it

may change its environment.

2. What events might have led to the

changes that occurred in your town or city?

3. What positive effect have humans had

on their environment? What negative effect

have humans had on their environment?

Section 6-1


Go to

Section:

I t t G bb ti d


51/54

1. List three ways in which other organisms have

proved to be a benefit to humans.

2. Compare biodiversity with other naturalresources, such as wood and fossil fuels. Do you

think biodiversity is a renewable or a

nonrenewable resource? Explain your answer.

3. What can be done to preserve the biodiversityof organisms?

Section 6-3


Go to

Section:

I t t G bb


52/54

How Much Should

It Cost?

You may have read that when something

becomes hard to obtain, its price usually

increases. Such is the case for materials like goldand diamonds, which are nonrenewable

resources. Using similar thinking, some

researchers believe that all the valuable services

provided by a healthy ecosystem should be

assigned a dollar value.

Interest Grabber

Go to

Section:

I t t G bb ti d


53/54

Rank the following items in order of their

importance to you. Then, next to each item, write

down how much you would be willing to pay for it. 1. Fresh, clean drinking water

2. Clean air to breathe

3. An endangered plant containing a substance

that can cure cancer

4. Gas for your family car

Section 6-4


Go to

Section:


54/54

Solar energy

Production of oxygen

Storage and recycling ofnutrients

Regulation of climate

Purification of water and airStorage and distribution offresh water

Food production

Nursery habits for wildlife

Detoxification of human and

industrial wasteNatural pest and diseasecontrol

Management of soil erosionand runoff

Section 6-4 Figure 6-22 Ecosystem Services

Go to
http://localhost/var/www/apps/conversion/tmp/Biology%20Main%20Menu.ppt

humans impact environment

Documents