Human Impact on the

Environment

We share the Earth…

with a whole lot of other creatures…

We don’t share very well….

Human Activities

Humans have always _______ the Earth’s

ecosystems:

altered

• Hunting, fishing, gathering of _____

• ___________ -- deliberate planting

of ______ and raising of _________

(made larger ___________ possible)

Agriculture

crops livestock

settlements

• Farming technology: _________,

_________, __________ and

____________ (one type of crop) –

which reduces ____________!

irrigation

fertilizers pesticides

monoculture

biodiversity

food

Ecological Succession

After a ___________, there are a

__________ series of changes that occur

over time.

disturbance predictable

Ecosystems may seem ______, but they are

constantly _________ in response to

________ and ________ disturbances.

stable

changing

natural human

Older inhabitants _____ and make room for

________ inhabitants.

die

newer

Primary Succession Describes changes on surfaces with no

_____. (Bare _____.) soil rock

________ species are the _____ to populate

an area (________ and ________).

Pioneer first

lichens mosses

When the pioneer species die,

their remains are

____________ to begin

forming ______.

broken down

soil

Over __________ of years, more soil is

added, making it possible for ______ plants

to grow.

hundreds

larger

Eventually, the

ecosystem will reach

the _______

community, which is

a _______ ecosystem.

climax

stable

Secondary Succession Secondary succession is to _______ the

ecosystem to its _______ conditions after

________ events (_____) or _______ events

(________).

restore

original

natural fire human

farming

**But some events can

___________ affect these

communities – and they

may not be able to

________ from

__________ activities...

dramatically

recover

long-term

Industrial Growth

The Industrial Revolution added

__________ to the atmosphere and ______

supplies.

pollution water

Burning of ______ fuels increases the

concentration of _____ in the atmosphere,

adding to the ____________ effect.

fossil

CO2

greenhouse

This also adds _____ to the atmosphere and

causes _________.

soot

acid rain

Cities produce large amounts of ________

that contaminate _____ and _______.

waste

soil water

Renewable/Nonrenewable

Renewable resources can ___________ if

______. (Example: _____)

regenerate

alive trees

Replanting doesn’t

restore the whole

__________! ecosystem

____________ is greatly reduced, and may

not be able to ________...

Biodiversity

recover

Nonenewable resources _______ be

____________ by ________ processes.

(Example: ___________)

cannot

replenished natural

fossil fuels

___________ development: a method of

using natural __________ without

_________ them.

Sustainable

resources

depleting

This provides for _______ needs without

causing __________ environmental

_________.

human

long-term

damage

Land Resources

Soil _____ be renewable – but can become

___________ damaged if mismanaged.

CAN

permanently

Good soil provides _________ and adequate

_________ and __________.

moisture

drainage nutrients

Removing plants causes _________ of

topsoil and will prevent further ________.

erosion

growth

Soil also needs _____ for _____________ to

return _________ to the ecosystem!

time decomposers

nutrients

Forest Resources

Wood is used for _______ and _______. homes paper

Trees also provide ________ for animals

and limit ________ of topsoil.

habitats

erosion

___________ forests (have ______ been cut

and are __________ of years old!) are

_____________!!!

Old-growth never

hundreds

nonrenewable

Forest _____________: ____________

harvest _______ trees to give the _________

trees a better chance for _________.

Management selectively

older younger

survival

Ocean Resources

______ are a source of food for ______ of

the world’s population!

Fish most

___________ takes the larger __________

stock, leaving the _________.

Overfishing breeding

juveniles

This __________ growth rates for the

species – and some may __________

permanently!

decreases

disappear

___________ fishing sets ______ for the

_____ of fish, size of ______ and _________

-- to ensure that _________ continues.

Sustainable limits

size catch season

breeding

Air Resources

_________ is any harmful material in the

_________, spread through ______, ____ or

______.

Pollution

biosphere land air

water

Burning of fossil fuels puts _________,

________ and ____________ into the air.

nitrates

sulfates particulates

These can cause _________, which can

damage ____ and _______ supplies and

destroy _______.

acid rain

soil water

plants

Biodiversity Biodiversity is the total of all ___________-

based _________ of all __________ in an

__________.

genetically

variation organisms

ecosystem

**Biodiversity is one of Earth’s greatest

________________!!! natural resources

We have found _____, __________ products

and __________ like _______________,

______ drugs and __________ medications!

food industrial

medicines antidepressants

heart anticancer

Many human activities are a _______ to

biodiversity.

threat

Habit Alteration: humans can _____ or

_______ habitats.

alter

destroy

This can _________ communities, causing

________ with fewer _______, smaller

___________ and less __________.

fragment

‘islands’ species

populations variation

This will make them

more __________ and

less able to ________

from disturbance.

vulnerable

recover

Wildlife products: used for _____, _____,

___________ or ___________ -- we have

hunted some animals to __________.

meat fur

‘medicine’ decoration

extinction

Pollution: we use __________ to control

insect populations, without realizing the

_________ caused to the whole

___________.

pesticides

damage

ecosystem

Conserving Biodiversity

We need to conserve biodiversity for

_________________. future generations

Conservation is the _____ management of

natural _________ to preserve ________ and

________.

wise

resources habitats

wildlife

Challenges to Conservation

• Captive _________ programs in zoos –

preserve only one _______ -- we should be

just as concerned about the ____________

between species in the __________!

breeding

species

interactions

ecosystem

• Limiting the __________ of resources

changes and ______ the way that people

____________.

harvesting

limits

earn a living

** Can cause severe financial _________,

but if steps aren’t taken to ________

resources, they may _________________!!!

hardship

protect

disappear forever

DDT and Biomagnification

DDT is a _________ that seemed perfect – it

was _______, worked against many different

______, and didn’t ____________ in the

environment.

pesticide

cheap

pests break down

BUT – it ________ into streams and rivers –

in _____ enough concentrations that no one

was concerned.

drained

low

In the water supply, DDT was taken up by

_______ and _________. plants bacteria

___________ eat plants. Because of the

________ loss between trophic levels, they

must eat _______ of plants – increasing the

DDT level ______ from plant level.

Herbivores

energy

LOTS

10 X

Carnivores must eat many __________,

which increases the DDT _____________ in

the bodies of the carnivores.

herbivores

concentration

Top carnivores have the _______ risk, and

suffer the greatest _______.

highest

effects

**Responsible for decrease in ______ and

_______ populations – caused fragile _____!

eagle

osprey eggs

Biological Controls

If you can’t use __________ to control pests

– what’s the solution?

chemicals

Find the pest’s ______________! natural enemy

We can use predators (_________),

parasitoids (wasps that lay _____ on

_______), pathogens (_________) or insects

that _______ specific _______.

ladybugs

eggs

larvae bacteria

target weeds

This method ________ pest populations

without ________ the rest of the

__________!

controls

harming

ecosystem

Invasive Species

Humans have ____________ species to

areas where they did not ________.

introduced

evolve

In many cases, these new species are better

________ to the new environment and able

to ____________ the native species!

adapted

out-compete

They also have no natural __________, so

there is no _______ on their population

________.

predators

check

growth

Invasive Species Examples:

Snakehead fish

Purple

loosestrife Gray squirrel

Asian carp

Zebra mussel

Major Environmental Concerns

There are 2 major concerns for the future of

Earth’s ecosystems:

Depletion of the Ozone Layer

Global Warming

Ozone Layer

Ozone is a _____ in the atmosphere that

________ harmful ____ rays from the sun –

like Earth’s ____________.

gas

absorbs UV

In the 1970’s, a _____ was discovered over

__________ -- and scientists found that

______ (chlorofluorocarbons) found in

_______ cans were making it larger.

‘sunscreen’

hole

Antarctica

CFC’s

aerosol

CFC’s are now ________ in the US – but

effects can linger for ____ years, and other

countries still use CFC’s…

banned

100

Global Climate Change

Life in the biosphere is _________ to live in

a very narrow range of _____________.

adapted

temperatures

Our global climate is getting ________,

which have serious side effects:

warmer

• _________ polar ice caps Melting

• Rising ______ levels at __________ water coastlines

• Destruction of __________ coral reefs

_________ evidence shows that _________

trends have happened in the past – but…

Geologic warming

Did we ______ this one? cause

Cutting _______ and burning _______ fuels

adds ____ to the atmosphere – much faster

than it can be ________.

forests fossil

CO2

cycled

Increased CO2 levels contribute to the

___________ effect and make the Earth

________.

greenhouse

warmer

Long-Term Effects

The average _______ temperature on the

Earth is expected to rise ______ by the year

_____.

surface

1-2 ºC

2050 This will cause:

• _________ in ________ areas Flooding coastal

• _________ during the ________ months Drought summer

• Change in ________ composition in

ecosystems

species

• Will alter ________ relationships as some

species become _______

feeding

extinct

The Bottom Line…?

Why does any of this matter?

EVERYTHING in the biosphere is

__________, so if we don’t make an effort to

_________ our resources, the next food

chain we destroy may be _______.

connected

preserve

OURS

Once it’s gone, it’s gone folks. No going

back.

We must be good _________ of the Earth –

we don’t own it –

we _______ it from our _________.

stewards

borrow children