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Chapter 12 Ecology: Module Hyperlinks

• 12.1 Ecology and society

• 12.2 The science of ecology

• 12.3 Abiotic factors

• 12.4 Populations

• 12.5 Population growth

• 12.6 Human population growth

• 12.7 Community interactions

• 12.8 Food webs

• 12.9 Species diversity

© 2017 Pearson Education, Inc.

Chapter 12 Ecology: Module Hyperlinks

• 12.10 Invasive species

• 12.11 Biodiversity

• 12.12 Terrestrial biomes

• 12.13 Aquatic biomes

• 12.14 Energy flow

• 12.15 Elements cycle

• 12.16 Water cycle

• 12.17 Ecological problems: causes

• 12.18 Ecological problems: solutions

• 12.19 Global climate change


12.1 Opening Questions: Ecology is

everyday.

• Ecologists study how organisms interact

with each other and their environment.

List all the organisms that you have

interacted with over the last 24 hours.

What was the nature of the relationship?

Was it positive or negative for both you

and them?

Chapter Table of Contents© 2017 Pearson Education, Inc.

12.1 Ecology is the study of organisms in

their environments.

• Ecology is the study of how organisms interact

with each other and with their environment.


Ecologists make verifiable

observations using the

discovery approach.

Hypothesis-driven ecology

science may be conducted

in the field or in the lab.

Chapter Table of Contents

12.1 Ecology can inform the philosophy and

social movement of environmentalism.

• Ecology is distinct from environmentalism,

a broad philosophy and social movement

that seeks to maintain environmental

quality.

• The science of

ecology provides

the basis for

understanding

environmental

problems.


12.1 Ecosystems provide valuable goods

and services that benefit human society.


Raw

materials

estimated

value:

>$2 trillion

Erosion

control

estimated

value:

>$16 trillion

Water

treatment

and filtration

estimated

value:

>$22 trillion

Recreation

estimated

value:

>$20 trillion


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12.1 Some important services are more

difficult to quantify in monetary terms.


Sustain

and define

cultures

Resources for

teaching and

learning

Scientific

research

Intrinsic

value


12.2 Opening questions: How much would

you pay for ice cream?

• Honeybees and native

insects pollinate many of

the crops that flavor our

ice cream.

• What if we had to replace

their service? How would

we?

• What would you be willing

to pay for your strawberry

or chocolate ice cream?

© 2017 Pearson Education, Inc. Chapter Table of Contents

12.2 Ecology can be studied at many levels.

• Ecology is the

scientific study of

organisms in their

environments.

• It is convenient to

divide ecology

into five

increasingly

comprehensive

levels.


Organismal

ecology

Population

ecology

Community

ecology

Ecosystem

ecology

Global

ecology


12.2 Ecology can be studied at many

levels: organismal ecology.

• Organismal

ecology focuses

on the ways that

organisms adapt to

their environments

through physiology

and behavior.


An organism is an

individual living being.

What type of questions

might an organismal

ecologist ask?



levels: population ecology.

• Population

ecology is

concerned with

the factors that

affect population

size, growth,

and density.


A population is a group

of individuals of the same

species living in the same

place at the same time.

What type of

questions might a

population ecologist

ask?



levels: community ecology.

• Questions in

community

ecology focus

on interactions

among species.


A community consists

of all the populations (of

multiple species) living

in a particular place.

What type of

questions might a

community ecologist

ask?


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levels: ecosystem ecology.

• Ecosystem

ecology is

concerned with

questions of

energy flow and

chemical cycling.


An ecosystem is all the

life living in a particular

area together with all the

nonliving components.

What type of

questions might an

ecosystem ecologist

ask?



levels: ecology of the biosphere.

• At a global scale,

ecologists can study

the influence of

energy and matter

on organisms across

the biosphere.


The biosphere is the

global ecosystem.

What type of questions

might an ecologist ask

about the biosphere?


12.2 All organisms interact with each other

and the nonliving ecosystems

• The ecosystem includes all living

organisms as well as nonliving factors

such as air, sunlight, wind, and water.

• The dynamics of every ecosystem depend

on two main processes:

1. Energy flow

2. Chemical

cycling


12.2 Energy flows through ecosystems.


12.2 Chemicals cycle through ecosystems:


12.3 Opening Questions: Shark week?

• Pick your favorite wild plant or animal.

• Pretend you can spend as much money as

you want and design new technologies if

you need to in order to collect data.


How would you study this species as an

organismal ecologist?

How would you study this species as an

ecosystem ecologist?


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12.3 The biosphere includes biotic and

abiotic factors.

• The living organisms of an ecosystem

constitute its biotic factors.

• The abiotic factors of

an ecosystem are its

nonliving components.


Abiotic factors can

have a profound effect

on the life within an

ecosystem.


12.3 Examples of abiotic factors include the

supply of energy and nutrients.

• The most important

abiotic factor is energy.

– Most ecosystems on

Earth are powered by

solar energy via sunlight.

• The availability of

inorganic nutrients can

impact plant growth.

– Examples are nitrogen

and phosphorous.


12.3 Other important abiotic factors

Wind

Temperature

Water availability

FireChapter Table of Contents© 2017 Pearson Education, Inc.

12.4 Opening Questions: How do abiotic

factors shape ecosystems?

• How do rain forests differ from deserts

in their abiotic factors?

• How might those differences result in

different biological communities?


12.4 Populations vary in density,

dispersion, and survivorship curves.

• Ecologists study populations in terms of

their density, dispersion patterns,

survivorship curves, and life histories.

• Collecting such data can provide insights

into the dynamics

of a population in

its ecosystem.


12.4 Population density and dispersion are

important ecological measurements.

• Population density is

the number of

members of a species

per unit area or volume

of the habitat.

• Dispersion patterns

are how individuals are

spaced within a

habitat.


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12.4 Age structure is the number of

individuals in different age groups.

• Comparing age structures of human populations

can provide insights into social conditions.


Which country will need more high schools built?


12.4 Survivorship curves graph the

percentage of individuals alive over time.

• Survivorship is the chance that an

individual member of a given population

will live to a particular age.


How do the curves vary among the three species?


12.5 Opening Questions: What patterns do

you expect?

What population dispersion patterns would

you expect for the following scenarios?

A. Territorial songbirds on their breeding

grounds

B. Trees that disperse as wind-blown seeds

C. Students in a classroom

D. Students in a classroom when free pizza is

delivered to the front of the room


• In its simplest terms, population size is

calculated from the number of births minus

the number of deaths.

• Ecologists have

developed idealized

models to help us

better understand

changes in

population size.

12.5 Growth models can predict changes in

population size.


12.5 Exponential population growth occurs

under ideal conditions.

• Imagine there are no predators, no

disease, and plenty of food.

• Over time, what do you expect will happen

to population size?

Exponential growth

occurs when the

population size of

each new generation

is a multiple of the

previous generation.


12.5 The exponential growth model

Exponential growth requires unlimited resources.


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• In real-world populations, there are

limiting factors, environmental constraints

that put a cap on the size of a population.

• The carrying capacity

is the maximum

population size that

can survive in an

environment.

12.5 Most populations cannot sustain

exponential growth indefinitely.


12.5 The logistic growth model incorporates

limiting factors.

• What happens if there are factors like

predators, disease, or food shortages?

• Over time, what do you expect will happen

to population size?

Logistic growth is

where the size of a

population grows

rapidly until it nears

its carrying capacity

for that environment.


12.5 The logistic growth model

Logistic growth includes limiting factors.


12.5 Limiting factors include two broad

categories.

• Density-dependent

factors are limiting

factors whose influence

is affected by population

density.

– Competition, disease

• Density-independent

factors are unrelated

to population density.

– Weather, environmental

disturbance


12.6 Opening Questions: What happened to

all the reindeer?

In 1944, the U.S. Coast Guard introduced 29 reindeer

to an island off Alaska. With no natural predators the

population reached 6,000 animals by 1963, leading to

concerns for the island’s vegetation. However, by 1966,

only 42 were alive. Weather records show that 1964

was exceptionally cold.

• Graph the reindeer population over time.

• Does the graph show exponential or logistic

growth (or both)? Explain.

• Did the population change due to density-

dependent or density-independent factors?


12.6 The total human population—currently

about 7.2 billion—continues to rise.

• Unlike nearly every natural population,

humans have demonstrated exponential

growth, especially over the last 250 years.


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12.6 Human population growth is

exponential.


12.6 Population age structure can inform

future population size.

• Current population growth is affected by the birth

rate 15 to 30 years ago, since that is when

today’s child-bearers were born.


Age structure

can be used to

project future

population

size.


12.7 Opening questions: Why are you in

college?

• In many countries around the world, the

most effective method for reducing

population growth (by dropping birth rates)

has been linked to increasing access for

girls to primary and secondary schools.


• Why is education for girls is so effective in

reducing the number of births per female?

• Does this suggest policy recommendations

to help stabilize our global population?


12.7 Interactions between species play

important roles in communities.

• Within a community, species interact with

members as they compete for food, water,

sunlight, or living space.


12.7 Competition occurs when two or more

species rely on similar limiting resources.

• Competition is mutually harmful.

• According to the competitive exclusion

principle, if the resources required by two

species are too similar, they cannot coexist.


12.7 Mutualism is a form of interspecies

interaction in which both species benefit.

• Mutualism is beneficial to both species.

– It often occurs among species that are

symbiotic, living in close physical association

with one another, but not all symbiotic

relationships are mutual.


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12.7 Some interactions are beneficial to

one species and harmful to the other.

• Predation is an

interaction in which

a predator species

kills and eats a prey

species.

• Herbivory is the

eating of plant parts

by an animal.


Cheetah and impala

Barrel cactusChapter Table of Contents

12.7 Some interactions are beneficial to

one species and harmful to the other.

• A parasite lives on or

in (but does not kill) a

host, from which it

obtains nutrients.

• Pathogens are

disease-causing

microorganisms.


Mouse flea

Chestnut blightChapter Table of Contents

12.8 Opening Questions: What happens

when species compete?

• Imagine that two species of related birds

live in the same habitat and eat similar

food items.

• Design a simple experiment to test the

competitive exclusion hypothesis.


12.8 Food webs describe multiple trophic

structures.

• Trophic structure

describes the feeding

relationships within a

community.

• Food chains and

food webs describe

the transfer of organic

material from one

trophic level to the

next.


12.8 A food chain is a simplified description

of one part of the trophic structure.


12.8 A food web interconnects multiple

food chains.


A food web of a

hypothetical

forest community

Arrows indicate

energy transfer or

“who eats whom.”


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12.8 Many toxins cannot be digested and

are passed from one tropic level to another.

• Biological magnification is the tendency of

toxins to become concentrated in a food chain.


Why are pregnant women told to limit their

consumption of tuna and other predatory fish?


12.9 Opening Questions: Which forest is

more diverse?

Consider these two forests:

• Are they equally diverse? Or would you consider

one forest more diverse than the other?


12.9 Species diversity includes both

species richness and abundance.

• Both forests have the same number of species,

or species richness (four in this example).



12.9 Species diversity includes both

species richness and abundance.

• However, the relative abundance, differs

between the two communities.



12.9 Keystone species can drive patterns of

species richness and diversity.

• A keystone species is a species that has

a disproportionately large effect on its

environment relative to its abundance.

• Ecologists studying

the Alaskan coast

discovered that a

decline in the sea

otter population

allowed sea urchins

to quickly multiply.


12.9 Communities are rarely static, and

disturbance is followed by recolonization.

• Primary succession occurs when an area has

been rendered virtually lifeless with no soil.


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12.9 Ecological disturbance often adds to

the diversity of habitats and communities.

• Secondary succession occurs after a

disturbance that kills much of the life in an area

but leaves the soil intact.

• After a disturbance, an area will be reoccupied

by a series of species. Ecological succession

may take hundreds or thousands of years.


12.10 Opening questions: Why do

introduced species sometimes take over?

In 1859, 24 rabbits were released on an Australian

ranch for game hunting. By 1900, the rabbit

population had increased to several hundred

million, spanning most of the continent.

Rabbit devastated landscape

in Australia – note the rabbits!

• What type of growth

curve did the introduced

rabbit population show?

• Why did the population

grow so rapidly?

Consider the ecology.


12.10 Invasive species disrupt ecosystems

as both predators and competitors.

• When non-native organisms are introduced

to a community, they can spread rapidly,

becoming an invasive species.

• Invasive species are now a leading cause

of extinctions of local populations.

Lionfish were introduced

into the Caribbean and

consumed other fish

voraciously.


12.10 Invasive species spread rapidly after

being introduced to a new environment.


Burmese pythons were set loose in

Florida.

Kudzu is a climbing vine,

introduced to the southern U.S.A rogue’s gallery of

invasive species


12.10 Once established, controlling invasive

species can be very difficult.

• Ecologists may implement biological

control, the intentional release of a

natural enemy.

The introduction of a stingless wasp has helped

keep populations of the invasive borer in check.


12.10 Biological control for invasive species

can have unintended consequences.

• In Hawaii and the Caribbean, growers

introduced the mongoose, a fierce hunter of rats.

Unfortunately, the mongooses also decimated

native reptiles, amphibians, and birds.


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12.10 Modern agriculture presents unique

challenges for biological control.

• Integrated pest management is a

method that utilizes several strategies:

– Biological control, pest-resistant crop

varieties, judicious use of chemicals, release

of sterile pests, and other biological and

behavioral changes.

Integrated pest management

has been used effectively for

cotton crops in India.


12.11 Opening Questions: Do you know

any invasive species?

• Every state now has at least a few

notorious invasive species. There are

likely some on your campus. Have you

heard of any in your area?

• What attributes might make a species

good at invading foreign ecosystems?


12.11 Biodiversity is a general term for the

variety of living things on Earth.

• Biodiversity includes:

Genetic

diversity

Species

diversity

Ecological

diversity


12.11 Genetic biodiversity refers to the

collection of genes within a population.

• Severely reducing genetic variation makes

the population less able to adapt to a

changing environment.

– Because virtually all the potatoes in the country

were genetically identical, the Irish potato blight

caused widespread crop failure and famine.


12.11 Species biodiversity refers to the

number of different species.

• Extinction is the irreversible loss of all

populations of a species.

• Ecologists estimate that at the current rate

half of all living plant

and animal species will

be extinct by the end of

this century.


12.11 Ecosystem biodiversity refers to the

variety of ecosystems found on Earth.

• The degradation of ecosystems threatens

ecosystem services, benefits that

ecosystems provide to people such as:

– Waste decomposition

– Water cycling

– Nutrient cycling

– Food production

– Recreation


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12.11 Biodiversity benefits people

and supports our society in many ways.

Biodiversity

provides both

current and

future food

crops.

Emu (Dromaius

novaehollandiae)Rosy periwinkle

(Catharanthus roseus)

Belize Barrier Reef

Nearly all of our

drugs are derived

from natural

products.

The economies of

many countries

depend on wildlife

preserves and

ecotourism.


12.11 Causes of biodiversity loss: habitat

destruction

• Habitat destruction

is the single greatest

threat to biodiversity.

– This includes

destruction of habitat

due to development,

agriculture, forestry,

mining, and dam

construction.

Brazilian rain forest being

cleared for agricultural use


12.11 Causes of biodiversity loss:

overharvesting

• Overharvesting species faster than they

can naturally replenish leads to a loss of

biodiversity.

– This includes hunting, fishing, and logging.


Overfishing has

decimated the

populations of

many wild fish.


12.11 Causes of biodiversity loss: invasive

species

• Invasive species are an increasingly

grave threat to biodiversity.

– The invader may have no natural predators

and can thus multiply unchecked, causing the

extinction of competitors or prey species.

Introduced to Guam,

brown tree snakes

have driven several

bird species to

extinction or near

extinction.


12.11 Causes of biodiversity loss: pollution

• Pollution of the air and water contributes

to biodiversity loss at the local, regional,

and global levels.

The Deepwater Horizon oil rig

explosion in 2010 released oil

into the Gulf of Mexico.


12.11 Causes of biodiversity loss: climate

change

• Global climate change impacts

biodiversity at both local and global scales.

– Ecologists predict declining biodiversity due to

changes in rainfall patterns, disruption of

seasonal patterns, rising temperatures, and

ocean acidification.

Coral bleaching is a

phenomenon that has been

linked with the increase in

water temperatures and

ocean acidification.


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12.12 Opening Questions: How does driving

a car impact the world’s coral reefs?

As CO2 levels rise in the atmosphere, about

25% of the excess CO2 is absorbed by the

oceans, lowering the pH of the ocean.

Review your earlier learning:• Why does CO2 lower the

ocean pH?

(review Chapter 2)

• What impacts might

ocean acidification have

on biodiversity?

Coral bleaching event


• A biome is a type of ecological community

that occupies a particular zone.

• The distribution of biomes depends largely

on two measures of climate: temperature

and rainfall.

• Terrestrial biomes

are identified primarily

by the types of

vegetation found

within them.

12.12 Ecologists categorize the Earth’s

surface into a series of biomes.


12.12 Some biomes are colder and drier.

Tundra is characterized

by dryness, bitter cold

temperatures, high

winds, and permafrost.

Polar ice is found in the

northernmost and

southernmost parts of

the Earth.


12.12 Deserts have very low rainfall.

There are both hot and cold deserts.

Most desert plants have evolved

adaptations that help them store

water.


Tropical forests

occur in wet, warm

climates near the

equator.

12.12 Forest biomes vary by latitude, but all

are found in relatively wet areas.

Coniferous forests

are dominated by

cone-bearing evergreens.

Temperate

broadleaf

forests occur in

regions of hot

summers, cold

winters, and

relatively

frequent rain.


12.12 Fire can play an important role in

maintaining some temperate biomes.

Temperate grasslands

are found in regions with

cold winters, low rainfall,

and periodic drought.


Savannas are warm,

fairly dry climates that

primarily contain

grasses with scattered

trees.

Chaparral is found in

coastal areas where

ocean currents produce

mild, rainy winters

and hot, dry summers

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12.13 Opening Questions: Water, water

everywhere, but not a drop to drink?

Some have argued that wars in the future

might be fought over access to fresh water.


List the reasons why is fresh water so

important to living things?

Do human societies all have equal

access to fresh water?


12.13 Freshwater biomes generally have

salt concentrations of less than 1%.

• Freshwater biomes include:


Lakes and ponds Rivers and streams Wetlands

Freshwater biomes cover less than 1% of the Earth’s

surface, but are home to nearly 6% of all species.


12.13 Marine biomes generally have water

that is about 3% salt by weight.

• Marine biomes include:


Coral reefs

The pelagic realm,

which has photic and

aphotic zones Deep sea


12.13 Where land and fresh water meet the

ocean are intermediate aquatic biomes.

• Intermediate aquatic biomes include:


Intertidal zones Estuaries


12.14 Opening Questions: For many

organisms is it home sweet biome?

• What challenges are similar for organisms

living in aquatic and terrestrial biomes?

• Which challenges for organisms are

unique to each environment?


12.14 Energy flows through ecosystems

from producers to consumers.

• Primary producers

convert solar energy

to chemical energy

via photosynthesis.

• Primary consumers

are herbivores that eat

primary producers.

• Secondary consumers

are carnivores that eat

primary consumers.


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12.14 Energy flows through ecosystems

along multiple levels of consumers.

• Tertiary consumers are

top-level predators.

– As trophic levels increase,

less energy is available at

each transfer.

• Decomposers are

organisms that break down

nonliving matter.

– Death at any level sends

energy to the decomposers.


12.14 The trophic structure of an ecosystem

describes the feeding relationships.

TROPHIC LEVEL 4

Tertiary consumers

TROPHIC LEVEL 3

Secondary consumers

TROPHIC LEVEL 2

Primary consumers

TROPHIC LEVEL 1

Primary producers

Decomposers break

down nonliving matter.

Energy enters an

ecosystem as

sunlight.

At each energy conversion heat is released.


12.14 Different ecosystems have different

rates of primary production.

• Biomass is the total amount of living

material in an ecosystem.

• Primary production measures the rate at

which solar energy is converted to biomass.


12.14 As energy is passed from one trophic

level to the next, most of it is lost as heat.

• From one trophic level

to the next, only around

10% of the energy

transfers.

• The cumulative loss of

energy means that each

level of trophic structure

can support fewer

organisms than the last.


12.14 Energy availability can be visualized

in an ecological pyramid.

Producers

Primary

Consumers

Secondary

Consumers

20,000 calories of primary production can feed 10 vegetarians for one

day or support one meat-eater for one day.


12.15 Opening Questions: Tiger farming?

• Across all human societies, the large

animals that were domesticated for food

were herbivores.

Why don’t we farm tigers?

If you decided you wanted to

farm tigers, how much space

would you need? Explain.


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12.15 Elements—such as carbon and

nitrogen—cycle through the biosphere.

• Energy flows through ecosystems.

• Elements cycle through ecosystems.

• Elements move from

abiotic reservoirs

(nonliving) such as the

air, soil, and water, to

biotic components

(living) of ecosystems in a

biogeochemical cycle.


12.15 Biogeochemical cycles occur both

locally and globally.


Geological processes

contribute to the abiotic

reservoirs.

Abiotic reservoirs − Includes the atmosphere,

rocks, and oceans

Biotic components − Includes producers,

consumers, and decomposers


12.15 The carbon cycle is an example of a



The carbon cycle is affected by human activities (shown in red), primarily

the burning of fossil fuels, which releases trapped carbon into the

atmosphere as CO2.


12.15 The nitrogen cycle is an example of a



Nitrogen is only available to living things after soil bacteria convert N2 to

compounds that plants can take up. Human effects on the nitrogen cycle

are shown in red.


12.16 Opening Questions: Ecosystem

trivia—you decide: true or false?

For each one, be prepared to explain your choice:

• True or false? The top of the food chain

has the most energy because energy

accumulates up the chain.

• True or false? Decomposers release

some energy into the soil that is then

cycled back to plants.

• True or false? The carbon cycle consists

only of photosynthesis and respiration.© 2017 Pearson Education, Inc. Chapter Table of Contents

12.16 All water on Earth is interconnected

in a global water cycle.

• Precipitation transfers water from the

atmosphere to the land.

• Conversely, evaporation from bodies of

water and transpiration from plants move

water from terrestrial sources to the

atmosphere.


Water erodes the land as

it moves to the ocean.


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Over the oceans, the net movement of water is from the sea into

the atmosphere. Over land, it is from the clouds down to the land.

12.16 The global water cycle


12.16 Fresh water, a valuable resource for

human societies, is relatively rare

• The vast majority of

water on Earth’s

surface is found in

the oceans.

• Less than 1% of the

water on Earth is

fresh water that

humans can access!


12.17 Opening Questions: What impact

does our population have on other

species?

The global human population is now over

7.2 billion and still growing.


How might the increasing human population

impact other species populations?

Explain using ecological concepts.


12.17 Humans depend on Earth for survival,

but we cause many ecological problems.

• Humans depend on the continued health

of Earth’s ecosystems for our own survival,

but we threaten the health of ecosystems

in several ways.

• No part of the

biosphere remains

unchanged by the

collective influence

of over 7 billion

humans.


12.17 The average American uses resources

at a higher rate than the world average.

• An ecological footprint is an estimate of

the amount of land and water required to

sustain one person.


12.17 The average world citizen uses more

resources than the planet can provide.


What are some ways we

can each reduce our

ecological footprint?


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12.17 Human impact: Forest destruction

• The primary cause of forest destruction is

clearing for agriculture.

Satellite images for one region

of a South American rain forest


12.17 Human impact: Freshwater shortages

• Some regions of the world are already

experiencing dire freshwater shortages,

and the problem will probably get worse in

the near future.

Polluted creek in Orange

County, California

Depleted water levels at

Arrowrock Dam, Idaho


12.17 Human impact: Declining species

• Endangered species are those with rapidly

declining populations.

An endangered hawksbill

turtle with researcher

The Canada lynx is considered

a threatened species.


12.18 Opening Questions: What does

biodiversity tell us?

• How is biodiversity related to ecosystem

health? Explain.

Biodiversity on a coral reef© 2017 Pearson Education, Inc. Chapter Table of Contents

12.18 Humans can work together to solve

ecological problems.

• Conservation biology

is a branch of ecology

that seeks to investigate

and reverse the loss of

biodiversity.

• The field of restoration

ecology uses ecological

principles to help repair

degraded areas.

Conservation and restoration ecology are both

expanding fields and are making significant progress.


12.18 Identifying conservation priority areas

can save much biodiversity.

Endemic species

are only found in

a relatively small

geographic area.

The ring-tailed lemur is endemic

to the island of Madagascar.

• Biodiversity hot spots are relatively small

areas with unusually high concentrations of

endemic species and endangered species.


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12.18 Conservation biologists recommend

preserving habitat in biodiversity hot spots.


12.18 When people are motivated to act,

species recovery can be dramatic.

• Bald eagles declined dramatically in the

lower 48 U.S. states due to habitat loss

and environmental toxins, primarily DDT.

• Today, bald

eagles have

recovered to

over 10,000

breeding pairs.


12.18 Conservation biologists also aim to

maintain ecosystem biodiversity.

• Fragmentation is the splitting of habitats

that isolates small populations.

• Corridors can be used to connect habitat

patches.

A bridge in the Netherlands

allows animals to access

areas otherwise separated

by a road.


12.18 Restoration ecologists work to repair

degraded habitats.

• This includes returning

native species and

bioremediation, the

use of living organisms

to detoxify polluted

ecosystems.

Workers plant sunflowers

to naturally remove toxins

from topsoil.


12.18 A realistic goal for the future is

promoting sustainable development.

• The goal of sustainable development is

to maintain the productivity of Earth’s

ecosystems indefinitely.

– Sensible, science-driven policies can help us

take corrective action now, while much hope

remains.

Education plays an

important role in

conserving our

biosphere.


12.19 Opening Questions: What are some

solutions?

Sustainable development aims to maintain

ecological process and ecosystems, while

also providing for human needs.

Imagine your state in 50 years. What

steps could we take today to both make

your state ecologically healthy and

provide for human needs (social,

cultural, and economic)?


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20

12.19 The accumulation of greenhouse

gases is causing global climate change.

• Greenhouse gases are airborne

chemicals that capture and hold heat

within Earth’s atmosphere.

• They include:

– Carbon dioxide (CO2)

– Methane (CH4)

– Nitrous oxide (N2O)

– Water (H2O) vapor


12.19 Global climate change: data on

greenhouse gases

• Atmospheric levels are higher now than at

any time in the past 800,000 years.


12.19 Global climate change: data on global

temperatures

• Since 1880, there has been an increase in

global surface temperatures.


12.19 Carbon dioxide is an important

greenhouse gas produced by our activities.

• Power generation and industry contribute

the most CO2 to the atmosphere.


CO2 contribution from

various human activities


12.19 Why is the Earth warming? We need

to understand the greenhouse effect.


12.19 Greenhouse gases act as an

atmospheric blanket, trapping heat.

• The greenhouse effect is vital to life on

Earth; without it, most of Earth’s surface

would be too cold to support life.

• The more greenhouse gases there are in

the atmosphere, the more heat is trapped.


The overwhelming consensus among

scientists is that the atmospheric

accumulation of greenhouse gases from

human activity is warming the Earth,

causing global climate change.


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21

12.19 Global climate change has many

far-reaching effects on ecosystems.

Ecosystem effects include:

– Habitat change or loss (shifting ranges)

– Polar melting (species loss)


12.19 Global climate change has many

far-reaching effects that impact human life.

– Coral bleaching (can mean the loss of entire

reef ecosystems)

– Increasing fires (result of earlier snow melt)


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