The Importance of Environmental Protection in Ecosystems

Ecosystems

Environment

al P

rotection

Navigation Table

Pre-Test

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•

Google assessment

Environmental Protection

Introduction

Environmental Protection

Environmental Protection

Introduction

Nature is beautiful and

marvelous to behold.

Humans need to protect the

environment.

•

After completing this lesson, each student should be

able to:

Objectives

Environmental Protection

⮚

Explain the benefits of protecting the environment

⮚

Provide examples of how humans damage the

environment

⮚

Suggest things that humans can do to protect the

environment

⮚

Explain how our good intentions for the environment

can have unintended bad consequences

Why It Matters

Environmental Protection

Environmental Protection

Why It Matters

Why Do We Have to Protect the Environment?

We can read it in the headlines daily, "The health of

ecosystems

 on which we and all other 

species

 depend is

deteriorating more rapidly than ever," stated Robert Watson

as part of a United Nations report on the environment. What

are we doing wrong? Mostly the problem is destruction of

habitat by:

•

industrial pollution

•

mining

•

farming

•

transporting species into habitats where they had not

been

Environmental Protection

Why It Matters

Why Do We Have to Protect the Environment?

Cont’d

What are some of the consequences?

∙

Worldwide, 780 million people do not have access to an

improved water source

∙

Two and a half billion people lack access to improved

sanitation

∙

More than 90% of the world’s population (mostly in large

cities of newly industrialized countries) breath air that is

dangerously unhealthy

∙

Hundreds of millions of poor farmers struggle to make a

living on poor land

∙

Whole countries are on the verge of famine

It is important to care about the environment. Thoughtful people can

care about the environment and at the same time see the need to

use nature for resources to satisfy the needs of our species.

Environmental Protection

Why It Matters

Why Do We Have to Protect the Environment?

Cont’d

The human species needs food and water. We need energy.

But we also need to protect the ecosystem niches that make

survival of our species possible. Beyond that, we need to

protect the niches for other species too. Why do niches

need protection?

1.

It's not nice to try to fool Mother Nature

. Ecosystems are

complicated. We have seen in these lessons that

complexity grows as we move up the ladder from cells to

organ systems to ecosystems. The history of our

attempts to manipulate ecosystems shows that we often

make mistakes and fail to see the unintended

consequences of our actions. Rich ecosystems are those

with many occupied niches. A change in any one niche is

likely to affect other niches and their occupant species.

Extinction

 is forever. We don't get a second chance.

Environmental Protection

Why It Matters

Why Do We Have to Protect the Environment?

Cont’d

2.  Environmental hazards are dangerous

. Our lakes and oceans have

become dumping grounds for dangerous chemicals (

pesticides

,

herbicides

, oil and refinery products, industrial wastes, and heavy

metals). Some of these toxins concentrate in food webs, such as

mercury in fish.

When large tracts of land are plowed, the exposed soil can erode during rainstorms. Much of this runoff flows to the sea, carrying with it agricultural

fertilizers and pesticides.

Source: 

NOAA

Environmental Protection

Why It Matters

Why Do We Have to Protect the Environment?

Cont’d

3.  Moral Obligation

. Our species owes its existence to the

living world that we share with other species. We owe

the living world a chance to perpetuate the life-creating

processes of natural selection, population dynamics, and

exchange cycles. We can only pay this debt by

protecting the environment

We humans are doing well as a species (see graph on next

slide). But our success comes at the expense of other

species. The 

United Nations Intergovernmental Science-

Policy Platform on Biodiversity and Ecosystem Services

(IPBES)

 warns that up to 1 million species are threatened

with extinction, many within decades. Over 40% of

amphibian species are threatened with extinction.

Environmental Protection

Why It Matters

Environmentalism and Politics

Many people in the world like to blame industrialized nations, especially the

United States, for destroying world ecosystems. It is true that industrialized

countries create much of the air pollution. But the problem will not be cured

by treaties that punish American companies for air pollution when

competing companies in other countries are exempt from regulation.

World population is

now over 7.5

billion. Over a 100-

years, the world

population has

more than tripled

and the growth

seems to be

continuing at an

increasing rate.

How long can the

human species

sustain such

growth?

Environmental Protection

Why It Matters

Environmentalism and Politics Cont’d

The really frightening prospect is the rapid pace of industrialization in many

Third World countries where unregulated industries expand to serve the

growth of the already huge populations. China and India each has more

than 1.3 billion people. What will world pollution be like when countries like

these become fully industrialized and modernized?

People who wish to protect the environment often become politically active.

They may come to believe that animals, and even plants, have

"rights." What do you think?

The idea of "rights" originally came from perceived inequalities in power

and privilege among 

humans

. "Rights" are something we United States

citizens have to pursue "life, liberty, and happiness.”

To extend the idea of rights across species quickly creates problems for

ecosystems. Does the wolf have a right to kill sheep? Or do sheep have a

right to be protected from predators? Does any species have a right to use

Nature's resources to perpetuate itself as a species? Does a species have a

right to destroy niches of other species in the process of exploiting nature

for survival of the species? And if we could agree on any of these rights, we

must answer the question, "Who issued these rights?"

Environmental Protection

Why It Matters

Environmentalism and Politics Cont’d

To argue in the political terms of "rights" misses the

point about how Nature's ecosystems work. Competition

between and within species is not only natural but

necessary for ecosystems to function well. Competition

and exercise of power becomes a problem only when it is

so destructive that an ecosystem itself becomes

threatened. Because humans have the greatest power to

damage ecosystems, humans also have the greatest

duty to protect ecosystems.

Environmental Protection

Why It Matters

Species Become Extinct. So What?

When a species becomes extinct, it no longer has any known living

individuals. A species arises only under a unique situation in which

there is a great deal of genetic diversity in a population that matches

the opportunities provided by a unique and currently unoccupied

niche.

How sad it is to learn that humans are driving so many species

toward extinction. Humans even deliberately kill (hunt) such

marvelous animals as elephants, rhinos, and gorillas. 

Click here

 or

here

 to see how students can get involved in conserving wildlife.

Hunters in Africa kill elephants just to get their ivory tusks.

Environmental Protection

Why It Matters

Species Become Extinct. So What? Cont’d

Appearance of new species depends critically on diversity of

genes and diversity of niches. But human activity is

producing the opposite at alarming rates. We eliminate

many niches by creating habitats suitable for our species

(example: we wipe out a forest to build a housing

development). We drive into extinction plant and animal

species at a rate of about one species per day. The unique

genes of these extinct plants and animals are lost

forever. Our 

selective breeding 

of plants and animals

creates uniformity in 

gene pools

. Evolution of new species,

which has usually taken thousands or millions of years, will

proceed at even slower rates. There is no way that the pace

of new species can keep up with the rate of extinction.

Environmental Protection

Why It Matters

Species Become Extinct. So What? Cont’d

So, does it matter, in the short term of human existence

thus far, that humans reduce genetic variation in plants and

animals and drive so many species into extinction? How

would you defend a position that it does matter?  Think in

terms of:

•

Do we devalue life by destroying it?

•

Do we change the course of future medicine by

making gene pools of plants and animals more

uniform?

Forest and jungle plants can be sources

of new medicines. Fanny Payaguaje,

medicinal plant garden curator in the

Amazon, guides a group of school

children through the medicinal plant

garden and points out a common, red-

berry “weed” used to treat skin

funguses—one of the most common

ailments for children in this moist,

tropical rainforest. From:

https://www.amazonfrontlines.org/chro

nicles/indigenous-youth-knowledge/

Environmental Protection

Why It Matters

Why Humans Are the Ecological Problem

Human population growth increases the demand for food,

water, and energy. At some point, the world population

must reach the earth's maximum capacity to support the

species. At that point, a remedy will be imposed in one or

more of the following forms:

∙

starvation

∙

mass 

epidemic

∙

war

All of these possibilities are ugly. Unfortunately, starvation,

epidemics, and war have already started in many parts of

the world. All three are common in certain parts of Africa.

The demand of humans for more food, more water, and

more energy not only threatens the human species, but it

also devastates ecosystems in which other species lives.

Environmental Protection

Why It Matters

Why Humans Are the Ecological Problem Cont’d

Consider agriculture. Clearing jungles to create pastures

changes a rich ecosystem that can support hundreds of

species into an impoverished one that supports only a few

species. The solution, according to Dr. Norman Borlaug, the

"Father of the Green Revolution," is not to destroy more

forests and jungles to create more farm land. The solution

is to make the land we currently use for farming even more

productive. The "Green Revolution" is well underway in

Third World countries where agricultural productivity is

being improved by better strains of plants and animals, and

selective use of fertilizer, herbicides, and pesticides. Modern

agricultural practices not only provide more food, but by

doing so without using more land, they produce a dramatic

conservation effect. To read more about Dr. Norman

Borlaug, 

click here

.

Click here 

for the United Nations Web site on world-wide

agriculture.

Environmental Protection

Why It Matters

Why Humans Are the Ecological Problem Cont’d

Political problems are preventing completion of the Green

Revolution.

∙

Many environmentalists object to the use of pesticides and

herbicides (and some even object to fertilizer).

∙

Local small farm owners typically do not have the knowledge

or expertise to use more productive farming practices. In

Mexico, 

Profepa

, the federal agency charged with protecting

Mexico’s natural resources, estimates that the country loses

about 1.3 million acres of forests each year, the fifth worst

deforestation rate in the world. Most of this deforested land

is used to expand poorly productive local farms and for

grazing for cattle.

∙

Many people object to genetic engineering, which could

create many strains of plants and animals that are both

disease resistant and grow more efficiently.

∙

The adding of more people by increasing population growth

makes demands on resources and causes the production of

more pollution.

Environmental Protection

Why It Matters

Why Humans Are the Ecological Problem Cont’d

Some environmentalists say that low-yield farming is more "

sustainable

."

But Borlaug says that Africa proves that low-yield farming is sustainable

only in the face of higher death rates. In many parts of Mexico, local

farmers farm in the same inefficient way that their Mayan ancestors did

2000 years ago. The problem of too many people with too little food is

made worse by population growth. Small local farmers around the world

are caught in a downward spiral of trying to have bigger inefficient farms

and they destroy the jungle and forests in the process.

Are humans smart enough to save themselves and their environment?

Maybe human evolution is not yet finished.

Simnai and Phillip

Tshuma, smallholder

farmers from Hwange,

Zimbabwe, show off

their sorghum crop

planted using fertilizers.

Photo: Busani Bafana

Retrieved from: 

United

Nations

How We Know

Environmental Protection

Environmental Protection

How We Know

We can know how safe our environment is if we monitor it: measure the

amount of toxins and other pollutants in our air, water, and soil. This

works, but we have to know which specific chemicals to monitor. This is not

always possible. Sometimes, we rely on biological monitors. Ever hear of

canaries in the coal mines? Canaries can act as an early warning signal.

They would die from toxic chemicals at much lower concentrations than

would humans. More recently, frogs are attracting attention as sentinels.

For example, male frog sexual development is impaired by a weed killer

(atrazine) at 1/30th of the level thought to be safe for people. In the past

decade, 200 frog species have declined and 20 are thought to have become

extinct.

But some things are obvious, right? Most people would agree that we

probably ought to clean up dirty air, dirty water, radioactive wastes, and

other such obvious sources of environmental hazards. Nor is there much

debate over such ecology-damaging events as soil erosion and chopping

down forests and jungle. A little common sense can help us know when we

are not protecting the environment.

Here are some issues that may not be so obvious:

Environmental Protection

How We Know

Fertilizer Run-off

Fertilizer that runs off into ponds and lakes

creates an environmental problem. Do you

know why? If you look at ponds and lakes

that drain heavily fertilized farm fields,

what do you suppose you would see? You

would see that the water was greenish

(like pea soup) or brown, that there was

much plant growth in it. If you looked at

water samples under the microscope, you

would see many single-celled organisms

and a wide range of insects and other

invertebrates. These organisms fix the

nitrogen from the fertilizer. However, most

plants cannot use this nitrogen and excess

nitrogen in the environment limits species

diversity. In our 

Water’s the Matter

Module

, there is a unit on measuring

nitrates and effects on water quality. Many

fertilizers also contain toxic chemicals than

can accumulate in the environment.

Toxic algae bloom in Florida was linked to fertilizer runoff.  

Click

here

 for more. Picture: Richard Graulich/The Palm Beach Post

Environmental Protection

How We Know

Antibiotic Resistance

How do we know if a given bacterium has

developed resistance to an antibiotic? The

original technique was to collect a sample of

the bacterium. For example, if you have a sore

throat, the doctor might swab the back of your

throat and send that swab to a laboratory. A

laboratory technician would gently rub the

swab on some growth medium in a round glass

dish and place little disks containing antibiotic

on top of the growth medium.  When the glass

dish is placed in a warm oven for a day or so,

the bacteria will grow all over the growth

medium, EXCEPT near the disks that contain

antibiotic that kills the bacteria. There will be a

clear zone, a halo, around each disk that has

the kind of antibiotic in it that prevents

bacterial growth. In recent years, this

technique is showing that more and more

kinds of antibiotics have lost their

effectiveness.

On this agar plate, a strain of bacteria is tested for resistance

to each of twelve different antibiotics. A clear zone around a

disc of the antibiotic indicate that the bacteria in the dish is

unable to survive in the presence of the test antibiotic.

Source

Environmental Protection

How We Know

Poor Farming Practices

What do you suppose will happen if a farmer plants his crops on a hillside?

Rains might wash away the soil, right? Elsewhere, we showed you a picture

of the Mississippi River and all the dirt that it contained. Where do you

suppose that dirt came from originally?

When rivers flood, the dirt they carry settles out and

helps to enrich the fields.  Much of that good soil is

carried in streams and rivers and does not settle out

until reaching the ocean.

A winding river with deposits along its banks.

What do you suppose would happen if you grew

crops year after year and burned off the field

instead of plowing it under? What happens to dead

plant matter? Do you know that it helps the soil

hold moisture? Plowing crops and keeping the dead

plant matter decreases the soil erosion problem

and also decreases the need for as much water.

Smoke billows from fires in the Yucatan. Source: NASA

Environmental Protection

How We Know

Running Out of Oil?

How do we know how much oil there is in the world?  We do

not know for certain. We can, however, make estimates.

These estimates are based on:

∙

The amount of oil coming out of wells and the rate

at which the production declines over time

∙

The size of new potential fields (as in Alaska) where

wells have not yet been drilled.

You could estimate oil fields by making small drill holes to

sample it. However, boreholes yield very narrow samples

and may drill right past substantial deposits of oil. Size of a

potential oil field is best determined by blasting sound

waves into the soil and recording the echo. Oil beneath the

surface will reflect sound waves differently from echoes

from rock. Complex computer analysis of the echo data in

three dimensions provides an estimate of the three-

dimensional size of pools of oil beneath the surface. This

technique is known as 

three-dimensional seismography

.

Environmental Protection

How We Know

Running Out of Oil? Cont’d

We know we are running out of oil, but estimates of the time left vary

enormously. Regardless of how much time we have left, we need to find

new sources of energy. We need to do that now, even if we have enough

oil, so that we can stop polluting our air and water with car exhaust and

gasoline refinery wastes.

As for preventing oil spills in our lakes and oceans, we know how to do that

just from observing how oil spills in the past have occurred. We just need

to:

∙

Replace old, leaky pipelines

∙

Avoid human errors in handling

of oil cargo

∙

Prevent accidents of tankers and

barges

∙

Prevent leaks and spills from

offshore drilling rigs

A controlled in-situ burn of

surface oil after the 2010

Deepwater Horizon/BP spill in the

Gulf of Mexico. (USCG)

Retrieved from: 

NOAA

Environmental Protection

How We Know

Forest Management

Much debate occurs over how to manage forests, because

it is not always clear how we know which practices

work.  You can't run controlled experiments, where one

plot of hundreds of acres is managed one way and

another plot is managed another way. You can't control

the climate so that both plots get the same amount of

rain, have the same growth of underbrush, or have the

same wind conditions.

When old trees are not

harvested, a large growth of

small brush creates fuel

during droughts.

So, we are left with common sense. Here is a partial list of

things to consider:

∙

If you chop down all the trees, replanting young ones might not

work if rains wash away the soil.

∙

If you don't allow any trees to be harvested, a lot of underbrush

will grow and create a huge fuel source when lightning (or a

camper) creates a forest fire.

∙

If you prohibit roads being built into forests, you keep the campers

out and reduce the chances that they will accidentally cause a fire.

∙

Prohibiting roads will not stop lightning from causing fires and it

makes it harder for fire fighters to control a fire.

Environmental Protection

How We Know

Overfishing

If too many fish (or lobsters or other sea life) are harvested, at first there

might not be any sign of harm. Eventually, however, the yield of harvest

will decrease and get less and less.

The only way to know whether a fish population is declining is to actually

count them. Because many species migrate, you have to do counts at

various times of the year.  Scuba divers often volunteer to perform such

fish counts. 

Click here

 to learn how scuba divers conduct the counts.

If you stop fishing, the reefs may become re-populated quickly. As the reef

habitat is vacated, the empty niches attract other animals from adjacent

areas to move in. There is a risk of extinction of many species. By

decreasing the population, you reduce the chances for successful

reproduction, and the problem might get so bad that you drive the

overfished species into extinction. Think of it like eating seed corn. If you

ate all the seed, there would be no way to plant a new crop.

So, the obvious solution is to restrict harvesting - by law if necessary. This

is a major effort in all state fish and game agencies. 

Click here

 for a listing

of state fish and game agencies throughout the U.S.

What We Know

Environmental Protection

Environmental Protection

What We Know

Humans change the environment in many ways, both accidental and

deliberate:

∙

We put chemicals into the soil, water, and air

∙

We chop down jungles and forests

Likewise, humans move animals around and introduce

them into niches they would not have encountered on

their own. Ever since the intercontinental travel began

by sea several hundred years ago, humans have been

re-distributing plant and animal life.

∙

Creatures stow away in cargo or on the

vessels or vehicles. Rats and cockroaches, for

example, have overrun the entire planet,

thanks to easy access to these means of

transportation.

•

Bacteria and virus move with the animals and

people that move about. A disease that pops

up anywhere in the world will eventually

spread everywhere. Recent examples include

AIDS

 and West Nile fever.

Sharing the Love?

Source: NOAA

Source: GPS.gov

Environmental Protection

What We Know

Sharing the Love?

Deliberate introduction of species into new environments can lead to

unintended consequences. These non-native organisms are called “

invasive

species

.” Examples include:

•

House sparrows, introduced 

into U.S. in 1850, now number in the hundreds of

millions and have crowded out many bird species.

•

Rabbits, introduced into Australia in 1859, thrived so well that they ate all the grass

down to the roots and killed shrubs and bushes by eating all the bark. An estimated

population of 750 million rabbits ate as much grass as would have been eaten by

100 million sheep. A viral disease that would kill rabbits was introduced around

1950. At first, 98% of rabbits were killed, but the survivors became resistant.

Today, their descendants are only about 25% susceptible.

•

Sheep and cattle have displaced countless communities of plants and animals that

could otherwise occupy the vast spaces that cattle and sheep require.

•

Agricultural crops (corn, wheat, etc.) destroy the niches that could support a wide

range of native species.

We are rapidly becoming one homogenous world. In the process, we must

be careful about upsetting the balance of nature. In the book, 

Rogue

Primate,

author John Livingston says that "Nature thrives on diversity and

variety. Anything that tends to reduce the normal complexity of

interrelationships is biologically destructive."

Environmental Protection

What We Know

Animal Destruction of the Environment-Example

When Charles Darwin first encountered Galapagos

Island, it was like a Garden of Eden, full of lush

vegetation and a huge range of animal and plant

species. Each species had specific physical

features that made it capable of operating within

its specific niche. For example, birds that cracked

nuts for food had large, tough jaws and beaks.

Birds that ate other kinds of food had beaks that

were specialized for that kind of food.

Satellite view of one of

the Galapagos Islands,

located 1200 kilometers

West of Ecuador. This

island has six active

volcanoes. Courtesy of

NASA.

A few goats had been set loose by sailors in the hope that their offspring

would provide food for ship personnel in the future. Today, goats have

taken over the islands. Some of the islands are now stripped of vegetation.

Before the arrival of goats, the islands had no plant-eating mammals

except turtles and iguanas that had low metabolism and ate little. Where

goats have stripped everything, turtles and iguanas now face extinction.

They don't eat much, but some vegetation is still essential for their

survival. Turtles are also under attack from other human-introduced

creatures: rats, dogs, and pigs dig up turtle eggs to eat. Iguanas are eaten

by dogs and pigs.

How sad it is to see this devastation of this living museum of evolution.

Environmental Protection

What We Know

Humans Are the Big Environmental Problem

We humans like to think of ourselves as superior to other species. We can

do things with our brains that no other species can. This attitude of

superiority has been called "speciesism."

By what standards do we measure the superiority of a species?

∙

Do we mean the ability create powerful tools and procedures that

can even change the ecological niche in which a species lives?

By that measure, humans are clearly superior to all species.

∙

Do we mean the total number of similar species?

The fossil record has revealed no more than about a half-dozen human-like

species. All have become extinct, except one (our species). Meanwhile,

bacteria and insect species number in the millions and have thrived for

millions of years.

∙

Do we mean the fitness to adapt to Nature's niches and thrive as a

species?

By that measure, humans fail to impress. Humans kill each other by

the millions -- in war and with diseases, such as AIDs. The modern

human species may be no more than 1/2 million years old, while

bacterial fossils have been found that are 3.5 

billion 

years old.

Environmental Protection

What We Know

Humans Are the Big Environmental Problem

Cont’d

Humans are not immune to extinction. As the earth's population grows to

the point where we have exhausted our resources or become so

overcrowded as to encourage devastating plagues or wars, extinction

becomes possible. More certain is that bacteria and bugs will be around

long after we are gone.

We humans dominate the earth and the other living things in it. We exploit

Nature to satisfy our desires. We whitewash our excessive desires by

defining them as 

rights

. We selfishly decide that our rights come first ahead

of those of other species that have no rights.  This viewpoint is then used

to justify our abuse of the environment and the damage that we do to other

species.

Have you heard of "rogue elephants," which

are elephants that run amok, causing

devastation everywhere they go? Author John

Livingston has called humans the "Rogue

Primate." Is that what we have become?

Environmental Protection

What We Know

Too Much of a Good Thing: 

Over-fertilization

Chemical fertilizers contain mostly nitrogen, phosphorous,

and potassium. They are used on crops because they make

crops grow better. Indeed, new genetic strains of crops

were developed because they could grow better if given

extra fertilizer that is not normally present in most soils.

The "Green Revolution" has saved millions of people from

starvation because fertilization of genetically improved

plants has allowed us to increase food production in order to

keep up with the demands of the rapid growth in human

population to 7.5 billion people. The argument has been

made that we should do even more fertilization, so that we

can grow more food on the same amount of land and thus

stop clearing of forests and farming on land that is subject

to washing away when it rains.

Environmental Protection

What We Know

Too Much of a Good Thing: 

Over-fertilization Cont’d

But what happens to extra fertilizer that is

not taken up by plants? For example,

fertilizer can be washed away in the runoff

when it rains. Where does this water go?  It

flows into creeks, ponds, rivers, and lakes.

What happens then? The plant life in the

water explodes, especially in response to the

nitrogen in fertilizer. So why is that a

problem? For one thing, it can choke the

waterway so that fish and other animal life

can no longer live there.

Too much nitrogen and phosphorus in the water can have

diverse and far-reaching impacts on public health, the

environment and the economy. Photo credit: Bill Yates.

Green algae, water lilies, and sea "weeds" can grow so fast that they

cannot rot as fast as they die. The decay of this massive growth robs the

water of oxygen, so fish cannot live. Ponds and lakes can become really

stinky. The overgrowth robs other living things in the water of light and

nutrients. It changes the niches and breeding grounds for other species and

typically drives them out. 

Click here

 to see examples of these problems.

We should also mention that fossil fuels are used to make fertilizers, and

we are already running out of fossil fuels. Extra growth of plants also

makes demands for more water. This is a real problem when farmland has

to be irrigated. There may not be enough water to go around.

Environmental Protection

What We Know

Too Much of a Good Thing: 

Antibiotic Use

Have you ever had a doctor prescribe antibiotics?

Did the doctor tell you to make certain that you

skip no doses and continue taking the medicine

until all pills are taken?  Why do you suppose this

is? If you stopped taking an antibiotic as soon as

you felt better, would there still be some bacteria

alive? Which ones would be most likely to have

survived up to this point? … the ones that had so

far resisted the antibiotic. In other words, you

could be creating a population of bacteria in your

body that had developed resistance to the

antibiotic.

What would happen if you took the same antibiotic all the time, that is,

every time you got a cold or felt bad. A few bacteria would survive, and at

some point, they might even start to thrive in the presence of the

antibiotic. The constant exposure to the same antibiotic would become a

natural selection force that could select the creation of a new species or

strain of bacteria that is resistant to that antibiotic. Now when you get sick

again with these resistant bacteria, your antibiotic will no longer work.

Environmental Protection

What We Know

Too Much of a Good Thing : 

Antibiotic Use Cont’d

This is exactly what has happened with penicillin. Penicillin, the first

antibiotic, was discovered in the 1940s and was very effective

against many kinds of bacteria. Now, because of overuse of

antibiotics, many of these bacterial strains are no longer affected by

penicillin.

The same problem has developed with several other antibiotics. The

more popular and widely used an antibiotic is, the more likely it will

lead to resistant strains of bacteria. Eventually, we may run out of

effective antibiotics. Then what?

Structure of penicillin.

Source: PubChem

Environmental Protection

What We Know

Depletion of Natural Resources: 

Poor Farming

Practices

Mayan farming

.

  Ancient Mayans in

Central America (from about 0 to

900 AD) had a "slash and burn"

method of farming. Each year after

the harvest, they would cut down all

the old plants and set the fields

afire. Then they would repeat the

process again the next year on the

same plot of ground. After about 7

years, the soil was so depleted of

nutrients and organic matter that it

had to be abandoned. They moved

on to clear another patch of ground.

Burning crop land (here in Brazil) depletes the soil and exposes it to wind

and rain erosion. Photo Ueslei Marcelino/Reuters

The Mayan population grew, sometimes to include cities with a hundred

thousand or more people. Soon, the farmers could not grow enough food

and there was no more good soil. Then the farmers started farming

marginal land, such as hillsides. That created other problems, because the

hillsides were easily eroded by rain. We may never know all the reasons

why the Mayan civilization disappeared, more or less suddenly around 900

AD. Two things are clear: 1) people abandoned the cities and returned to

simpler living, and 2) massive farming efforts could no longer be sustained.

Environmental Protection

What We Know

Depletion of Natural Resources: 

Poor Farming Practices

Cont’d

Oklahoma Dust Bowl.

  In the 1930s in the U.S., most of Oklahoma

and much of West Texas turned into a dust bowl because of a

drought.

Trees were cut down and grassland was turned into crop land. The

soil then became exposed to erosion from rain and wind. When

drought came, the land became worthless, unable to grow anything.

The air was choked with dust. Many farmers had to abandon the land

and move to other states, such as California. 

Click here

 to read the

story of the Dust Bowl.

Dust cloud rolling over western Kansas town, February 21, 1935

Environmental Protection

What We Know

Depletion of Natural Resources: 

Over-fishing

People who live on islands are very dependent on the fish

life around them. As an island becomes more populated with

people, the demand for food from the sea can outstrip the

source.

This has happened recently on the islands off the coast of

Honduras. The people there are very poor. Their struggles

were only made worse when they depleted the fish and sea

creatures. Such problems were made even worse when a

seafood restaurant chain set up a factory there for

processing lobster and fish. It didn't take long to exhaust

the sea's supply.

Coral reefs shelter and feed many fish.

Where did all the fish go?

Environmental Protection

What We Know

Depletion of Natural Resources: 

Over-fishing Cont’d

Over-fishing not only threatens the human food supply but

also that of other species that feed on sea life. One example

of a species threatened in this way is the Russian Brown

bear.

One hopeful sign is 

fish hatcheries

, where fish are raised in

captivity. For more on the world crisis in over-fishing, 

click

here

.

Environmental Protection

What We Know

Oil Depletion

Do you know where gasoline comes from? It comes from

processing oil. Where does most of the world's oil come

from? The oil that we pump out of the ground today took

millions of years to make. So our oil supplies are not

renewable -- once gone, gone forever.

An oil shortage is inevitable. Some analysts think that

shortages may develop, even as soon as in the next few

years. Then what? Prices will go up. Oil and gas may get so

scarce that people start wars. What can we do? One option

is to drill more wells. One problem is that oil wells create

hazards to wildlife if there are spills from tankers or breaks

in pipelines. On the other hand, if new wells only maintain

our current supplies, no additional hazards are created.

Environmental Protection

What We Know

Oil Depletion Cont’d

Many people are trying to stop all new drilling, especially in wildlife areas

such as  

Arctic National Wildlife Refuge

  (ANWR) in Alaska. Others argue

that we cannot develop alternatives to gasoline fast enough and that there

are responsible ways to drill for oil in wildlife areas (

click here

 to see their

arguments). These debates influence our national energy policy and laws

passed by Congress.

Arctic National Wildlife Refuge in Alaska

Source: U.S. FWS

So, what to do? Of course, we should do the research needed to develop

other sources of energy. In the meanwhile, we must get new sources of oil.

And in the process, we must be careful not to add a burden on the

environment.

Environmental Protection

What We Know

Success Stories

Environmental Hazards Can be Eliminated: Unleaded Gasoline

For about 80 years, lead was used as an

additive in gasoline to make car engines run

smoother. It became the primary source of lead

pollution in the United States. Lead poisoning

causes serious effects, especially on the brains

of babies and young children. See our Hazards

discussion of lead.

In 1990, amendments to the Clean Air Act were enacted to phase out the

use of lead in gasoline by the year 1995. Benefits occurred quickly. One

study shows that blood-lead levels declined by 80 percent from 1976 to

1999 in American children one to five years old. The European Union has

banned the use of lead in gasoline and the World Bank has urged all

countries to do so.

Since 2002 the Partnership for Clean Fuels and Vehicles,

within the United Nations Environment Program has been working to finish

the leaded gas phase-out. As of 2017, only six countries continue to use

leaded gasoline. 

Click here

 for a quick overview of the history of lead use in

gasoline.

Environmental Protection

What We Know

Success Stories Cont’d

Endangered Species Can Be Saved

In an earlier unit, we talked about how conservation efforts seem to have

saved the American Bald Eagle and the Whooping Crane from

extinction. There are other modern-day examples of preserving species.

For decades, biologists at various

institutions in Mexico and Texas have

developed programs to save the Kemp’s

ridley sea turtle species. The Kemp’s

ridley turtle is the world’s most

endangered sea turtle. Humans had

nearly destroyed the species by

harvesting the eggs that the turtles laid

on the Gulf Coast beaches. Today, under

strict protection, we are cautiously

optimistic that the population is on its

way to recovery. 

Click here

 or 

here

for

more information.

Source: NPS

Environmental Protection

What We Know

Unintended Consequences of Conservation Efforts

DDT Example

Have you read the Rachel Carson story yet

(see 

Story Time

)?  Rachel Carson worked at

a time when DDT was a common

insecticide.  Everyone thought it was about

the safest bug killer available, and it was

used with apparent success for many years.

But then people noticed that certain bird

species populations were declining. Especially

alarming was the U.S. national symbol, the

bald eagle. 

Click here

 to read about the eagle

recovery program. Closer study revealed that

bald eagle eggs were cracking and preventing

chicks from developing and hatching. Without

reproduction, no species can survive. The

cause was attributed to DDT, which causes

thinning of egg shells. This was an

unintended consequence of using the

insecticide. And so DDT was banned from use

in the U.S. and many countries of the world.

A Bald Eagle lands in the top of a tree as a good hunting

vantage point.

Source: NPS

Environmental Protection

What We Know

Unintended Consequences of Conservation Efforts

Cont’d

But now there is yet another unintended consequence. 

Malaria

 in tropical

countries is spreading rapidly. Malaria is caused by a blood parasite that is

transmitted from one person to another by mosquito bites. Mosquitoes are

developing resistance to the insecticides that we have used as substitutes

for DDT. Mosquitoes might also eventually develop resistance to DDT. The

point is that we need a wide array of insecticides to keep one step ahead of

resistance changes in mosquito populations.

Mosquito on human skin.

From: CDC

Environmental Protection

What We Know

Unintended Consequences of Conservation Efforts

Cont’d

Mosquito populations have increased 10-fold over that last

50 years in areas of the United States. Similar findings are

reported in other countries. This increase can cause the

increased spread of mosquito-borne diseases like malaria.

Some scientists estimate that one billion or more new

infections could be possible by the end of the century. DDT

was, and is, our cheapest insecticide, and Third World

countries cannot control mosquito populations without

cheap insecticides. DDT is now banned in the United States

for agriculture use. It is also banned in some 170 other

countries worldwide. While we have saved some bird

species, we have allowed human malaria to kill thousands

more people around the world. The fact that DDT is “good”

because it saves lives, and “not safe” because it has health

and environmental consequences, raises ethical issues. 

Click

here

for more.

Environmental Protection

What We Know

Unintended Consequences of Conservation Efforts Cont’d

Gasohol Example

Clearly, we must stop using so much fossil fuel, such as oil, which is used to

make gasoline for our cars and trucks.  Fossil fuels, once burned, cannot be

replaced. They are not renewable.  In a world that will someday run out of

oil (estimates range from 20 to 100 years), we simply must find

alternatives.

One idea is to add alcohol to gasoline to reduce

the amount of fossil fuel needed for vehicles.

This combination is known as “gasohol.”

Alcohol, made from fermenting grain or crop

residues and wood, is renewable. Alcohol

would also reduce tailpipe emissions that

contribute greatly to our air pollution. A recent

study found that greenhouse gas (GHG)

emissions from corn ethanol are about 39

percent lower than gasoline on energy

equivalent basis. Moreover, a gasohol program

would provide a new market for corn and crop

farmers.

Government programs help farmers find a new

market for their corn: gasohol.

Environmental Protection

What We Know

Unintended Consequences of Conservation Efforts

Cont’d

Questions still arise about the benefit of producing and

using ethanol. It was originally thought that it takes more

energy to produce the corn and refine the ethanol than the

ethanol actually provides. Recent studies investigating more

efficient farming methods and better refining technology

show that ethanol produced from corn demonstrates a

positive energy balance, meaning that the process of

producing ethanol fuel does not require more energy than

the amount of energy contained in the fuel itself. However,

ethanol’s energy balance is not as high as fossil fuels.

Debates continue about the comparison of efficiency of

gasohol vs. gasoline.

Even the cleaner air claim is open to debate. The

Environmental Protection Agency suspects that alcohol

production plants are polluting the air with carbon

monoxide, methanol, and other chemicals.

Environmental Protection

What We Know

Forest Fire Examples

Forest conservation efforts have resulted in state and federal laws that

protect national forests from timber cutting. To keep the forests in their

natural pristine state, roads in the forests have been prohibited. Whenever

forest fires are started by lightning, they are put out as quickly as possible.

All this seems logical. But there is an unintended consequence.

Lightning has been starting forest fires for

centuries.

Environmental Protection

What We Know

Forest Fire Examples Cont’d

Our national forests are now overgrown with trees and brush. Much of the

forest floor is covered in dead brush and timber from insect destruction. In

other words, the national forests are loaded with fuel, and fires, once they

start, burn excessively and rapidly. A combination of severe drought, high

temperatures, and strong winds created explosively combustible conditions

that resulted in the massive fires in Colorado and Arizona in the summer of

2002.

Firefighters cannot control these fires, because they are so big and because

there are not enough roads to get into the forests to build firebreaks. Not

only are the trees destroyed, but the animals and birds that live in the

forest are either killed or driven out of their habitats. The problems are

made even worse because more and more people who love the forests want

to build homes there. So now, shortsighted forest management policies not

only create more devastation of the forest when a fire does start but also

increases the destruction of expensive homes.

Environmental Protection

What We Know

Forest Fire Examples Cont’d

Yellowstone National Park's 2.2 million acres had a serious 

fire in

1988

. Park managers and fire behavior specialists allowed a portion of the

naturally caused (caused by lightning) fires to burn. Some of those fires

burned out naturally. However, due to unusually extreme dry conditions,

several burned on. The forest was devastated. But the forest regenerated

itself in a few years. It was thought that this newly regenerated forest

would be more resistant to fires, but this same area burned again in 2016.

These fires, and the response of the forests to these fires, have ushered in

a new way of thinking about forest management.

The 2016 Maple Fire burns young

lodgepole pine forests that regenerated

after the 1988 Yellowstone Fires.

Historically, fires in Yellowstone occurred

at 100-300 year intervals, but reburns like

this are expected to become more common

as climate continues to warm. 

Photo

courtesy of the National Park Service.

Environmental Protection

What We Know

Forest Fire Examples Cont’d

The lessons that forest managers have learned include that it may be

a good idea to allow limited timber cutting in forests. Likewise, we

should allow loggers to build roads in forests, which have the benefit

of providing access to firefighters if and when a forest fire breaks

out. Click 

here

 for a discussion of logging and fire management.

Other options for fire management are prescribed or controlled

burns, mechanical removal of vegetation by bulldozers or wood

chippers, and better preparation of community members and

firefighters. Click 

here

 for more on forest fire management.

A firefighter uses a hose to quell flames near the Norris Museum on Black Saturday – August 20,

1988.NPS / Jeff Henry

Rachel Carson (1907-1964)

Storytime

Environmental Protection

Books can pry open closed minds. The

books by Rachel Carson helped to open

the minds of government regulators,

executives in the chemical industry, and

the general public about the

environment and the dangers of

insecticides and herbicides. Just as

mighty forests spring from tiny seeds,

Rachel’s powerful books sprang from her

childhood fascination with nature.

Rachel Carson holding her book 

Silent Spring

Source: Library of Congress

Early Life

Environmental Protection

Storytime

Rachel grew up loving nature and exploring its wonders.

She thought that everybody should enjoy nature. Rachel

wrote: "The pleasures, the values of contact with the

natural world are not reserved for the scientist. They are

available to anyone who will place himself under the

influence of a lonely mountain top – or the sea – or the

stillness of a forest; or who will stop to think about so small

a thing as the mystery of a growing seed."

She loved the Beatrix Potter stories about Peter Rabbit and

other animals and the picture books her mother read to

her.  She had, from a very young age, an especially intense

fascination and curiosity about everything that lived in the

ocean, even though she grew up in Springdale,

Pennsylvania, miles from the seashore!

Early Life Continued

Environmental Protection

Storytime

Rachel grew up on 64 acres of peaceful farmland that had

an orchard, a few farm animals and some woods. The

delicate ecosystem of the Allegheny River was a daily

encounter for her, and she enjoyed learning about all the

birds and wildlife of the area.

On this land there were many fossilized ocean-dwelling

shells that Rachel and her neighbors collected.  These fossils

from millions of years ago sparked her curiosity about the

ocean that she had only read about in books or heard about

from her mother.

Rachel’s mom was the one who introduced her to the

wonders of nature, and young Rachel spent many hours

with her mom exploring on their homestead.

Early Life Continued

Environmental Protection

Storytime

Her dad was a self-declared salesman, who never seemed to make his

dreams a reality. He had grand plans to make the farm into a subdivision

for the growing town of Springdale (which grew in the opposite direction

from the farm).  He was known for moving and leaving many debts unpaid.

The farmhouse was simple, and reflected the family’s economic status.

There was a lean-to kitchen added to the side of the house. The house

never had indoor plumbing while Rachel lived there (1907-1925), and it

was without electricity when they moved in. Among the farm's several

outbuildings, there was a large gable-roofed barn, a matching garage, a

chicken coop, and a springhouse (which supplied them with fresh water and

was used to keep foods cool, since they had no refrigerator).

While they had plenty of land, cash was always in short supply for the

Carson family. Over the years, they had to sell off blocks of the farm.

Today Rachel’s homestead is preserved by the Rachel Carson Homestead

Association.  There they hold tours and classes, and visitors can experience

the surroundings that influenced and taught Rachel as a young child.

Schooling

Environmental Protection

Storytime

Rachel had only a few friends in childhood, which could have been due to

their isolation or to the fact that any friend had to first win the approval of

Rachel’s mom. One such friend was Charlotte Fisher. She would bring the

Carsons loads of books whenever her family went to Pittsburgh. This was

especially important since Springdale had no library at the time, and Rachel

loved to read and write.

Rachel Carson at work.

Rachel learned to read at a young age,

and decided quite early in life that she

would become a writer. She liked

school, possibly because she learned to

read early. She would write poetry and

bind it together as a gift for her

Dad. When she was ten, she decided to

submit a story to a magazine for

publication. By the time she was 11,

Rachel got her first story published in

the children’s section of 

St. Nicholas

Magazine

.

Schooling Continued

Environmental Protection

Storytime

Rachel said many years later: “I can remember no time, even in the earliest

of childhood, when I didn’t assume I was going to be a writer.  Also, I can

remember no time when I wasn’t interested in the out-of-doors and the

whole world of nature. Those interests, I know, I inherited from my mother

and have always shared with her.”

Her mom was determined that Rachel should go

to college, even though the family did not have

the money. Rachel wanted to attend Pennsylvania

College For Women. It was founded as a

Presbyterian liberal arts college for women and

was a good choice. Her mom had also gone to a

women’s Presbyterian school (Washington Female

Seminary, Washington, Pennsylvania). Rachel was

initially awarded a $100 scholarship, but the

college president, Cora Coolidge, learned about

her circumstances and persuaded private sources

to pay for Rachel’s tuition her freshman year.

Rachel appreciated the confidence others had in

her and was determined to prove herself worthy

of such support.

Schooling Continued

Environmental Protection

Storytime

Rachel was strong-willed and wasn’t easily influenced by what others said

or did. While other girls partied at school, Rachel studied. She also landed a

job with the college paper 

The Arrow

, which published her works. Two of

these essays, “Master of the Ship’s Light” and “Cape Arrowhead” show how

attracted to the ocean she was – even though she still hadn’t seen it!

Her second year in college was a major turning point. She had to meet the

science requirement by taking Biology.  She felt surely she would not like

Biology, but was quite surprised – she LOVED it! Biology gave new meaning

and understanding of the nature that she had always loved. Biology

answered many questions she had about nature, but above all, she saw

beyond the difficult words to see scientists’ awe and wonder at life itself.

In her third year of college, Rachel decided to change her major. Many

people thought she was crazy – everyone knew she was a writer!! Again

– she didn’t follow what everyone else thought she should do – she

followed her heart – and her heart’s desire was marine biology. She was

still looking for her ocean.

Schooling Continued

Environmental Protection

Storytime

Money problems were solved her senior year when her Dad signed over

several lots of the original farm to Rachel. She used the land as collateral

for the $1,600 she needed for her education. It was also during her junior

and senior years that she began to enjoy college life – joining team sports

and science club and continuing to work for the newspaper.

She graduated magna cum laude (which means “with great honor”) in

June, 1929. From there she accepted a scholarship to do graduate work at

Johns Hopkins University. She worked that summer at the famous 

Marine

Biological Laboratory

 in Massachusetts. This was her first view of the

ocean. She later described this time as “the happiest days of my life.” She

did field work, combed beaches, waded in the surf, explored, and collected

specimens.

Rachel graduated in 1932 from Johns Hopkins, and then she began to work

for the 

U.S. Bureau of Fisheries

(now part of the U.S. Fish and Wildlife

Service). Her boss took a great risk in hiring a woman scientist, but was

quite pleased with her work. She had a gift for writing and combined this

with her scientific knowledge. He even told her some writings were too

good for government publication. He recommended that she submit the

paper to the 

Atlantic Monthly

. She mumbled her thanks and threw that

manuscript in a drawer thinking it wasn’t good enough.

Writing Up a Storm

Environmental Protection

Storytime

She continued to work for the government and continued to write about

nature.  Just before World War II she published her first book 

Under the Sea

Wind

. After Pearl Harbor was attacked, all book sales plummeted, and she

only earned $1000 for it. Her part in the war effort (working for the 

U.S. Fish

and Wildlife Service

), was to encourage Americans to eat fish instead of the

red meat that was sent off for the troops. She was promoted rapidly, and in

1947 became the Editor-in-Chief of the Information Division of the Fish and

Wildlife Service.

While the war effort kept her busy, and the financial rewards

of the first book weren’t great, she still wanted to write

another. This time it would be a book about the ocean and

its various creatures. As the book took form, the publishers

realized that the chapters would make excellent magazine

articles.  However, these articles were turned down by the

Saturday Evening Post

,

 National Geographic

 and several

other magazines. Finally, in 1951, 

The New Yorker

 published

some of her articles, which eventually became about half of

the book (

The Sea Around Us

). 

Soon after the book came

out, the publisher had to go back to press and print

more! Such popularity helped gain recognition for her first

book. Eventually, both books were on the best-seller list.

Writing Up a Storm Continued

Environmental Protection

Storytime

Other books followed, including 

Help Your Child to Wonder

 (1956), and 

Our

Ever-Changing Shore

 (1957).  In all her writings, Rachel incorporated her

view that humans were only part of the ecosystems they inhabited, yet had

the greatest power to damage those ecosystems.

Then it happened.  A letter was given to her that changed her life, and our

lives too as a result.  In 1957 she received a letter written by Olga Huckins

directed to the Editor of the 

Boston Herald

 about the 

insecticide DDT

and

the harm it was doing to birds and fish.

DDT

Writing Up a Storm Continued

Environmental Protection

Storytime

Government officials (encouraged by the pesticide

companies) did not want to do any research on possible

harmful effects of DDT.  In her letter, Olga described the

deaths of fish and birds caused by DDT. Although these

were unintended consequences, the grim facts about DDT

kept piling up. Rachel knew that a book had to be written

about this problem, but after several attempts to encourage

others to do it, she decided she was the best one for the

job. She knew it had to be well documented and scientific,

but at the same time be easy to read for non-scientists.

"I may not like what I see," she wrote, "but it does no good

to ignore it, and it's worse than useless to go on repeating

the old 'eternal verities' that are no more eternal than the

hills of the poets. So it seems time someone wrote of life in

the light of the truth as it now appears to us."

Writing Up a Storm Continued

Environmental Protection

Storytime

Her personal life took a turn for the worse through all this. In 1960, she

had a breast tumor, which the doctor said was benign. By the end of the

year, she learned that his diagnosis was wrong, and the cancer was

spreading. She had several other tragedies during the course of her work.

Her sister died, leaving her children for Rachel to raise. Her mom, who had

encouraged her the most, became sick and died. In addition, Rachel’s

cancer became terminal. Though she was bedridden at times, and always

tackling financial problems for the family as well, she continued her work

on the book.

Her book, 

Silent Spring

, was published (1962) and was an instant sensation

(

click here

to read about this book's impact). While Rachel was attacked by

pesticide companies and some government officials for her book, she knew

her research and the facts were sound. Because of this, she was called to

speak to the U.S. Congress in 1963. She encouraged Congress to establish

a government agency to oversee all issues of environmental protection. A

federal agency was created, the 

Environmental Protection Agency

(EPA). One of the first things this agency did was to restrict the use of DDT

because of its unforeseen harmful effects on the environment. Rachel did

not live to see her work bear fruit. She died just before she turned 57 in

April, 1964. In her memory, 

a Silent Spring Institute

has been created to

study the possibility that pesticides might cause breast cancer.

Rachel’s Legacy

Environmental Protection

Storytime

Rachel’s writings and efforts influenced people all over

America to be more aware of the delicate balance of

nature.  We now have recycling centers, cleaner air and

water, and more awareness of the fragility of ecosystems.

But Rachel's most important contribution was making

people aware that human activity can have unintended

consequences on the environment. For a short video

biography of Rachel Carson, 

click here

.

References

Environmental Protection

Storytime

Henrickson, John.  1991. 

Rachel Carson, The Environmental

Movement

.  The Millbrook Press.  Brookfield, Connecticut.

Lear, Linda.  1997. 

 Rachel Carson:  Witness for Nature

.  Henry Holt and

Company.  New York, NY.

Vare, Ethlie Ann and Ptacek, Greg.  1988. 

Mothers of Invention:  From the

Bra to the Bomb:  Forgotten Women and Their Unforgettable Ideas

.

William Morrow and Company, Inc., New York, NY.

Associated Press. . (1963). How silent the spring [Photograph]. Retrieved

from 

https://www.loc.gov/pictures/item/93506538/

[Rachel Carson at work Photograph]. 

Retrieved From

https://rachelcarsoncouncil.org/about-rcc/about-rachel-carson/rachel-

carsons-legacy/

www.rachelcarsonhomestead.org

www.rachelcarson.org/

www.chatham.edu

Activities

Environmental Protection

Click to download an activity

Environmental Protection

Activities

•

Student Activity Sheet #1- A Global Warming Experiment

•

Student Activity Sheet #3- Local Environmental Health Hazards

•

Student Activity Sheet #4- A Case for Protecting the Environment

•

Student Activity Sheet #5- Modeling Antibiotic Resistance

•

Student Activity Sheet #8- Ecosystem Enigmas

•

Student Activity Sheet #9- Freddie the Fish

Self-Study Game

Environmental Protection

Click to play a game

Environmental Protection

Self-Study Game

•

Quizizz

Post-Test

Environmental Protection

Click below to take the post-test for this unit!

•

Google assessment

Glossary

epidemic

 – an abnormally widespread occurrence of an infectious disease

at one time. 

Return to Why It Matters

extinction

 - 

when a species of animals dies off completely from the earth.

Return to Why It Matters

gene pool

 – set of all of a population’s genetic material at a given point.

Return to Why It Matters

herbicide

 – a substance toxic to plants, used to kill unwanted vegetation.

Return to Why It Matters

HIV/AIDS 

– Human Immunodeficiency Virus is a virus that weakens a

person’s immune system by infecting helper T cells. It can be spread

through by contact of bodily fluids (blood, semen/pre-seminal fluid, rectal

and vaginal fluid, and breast milk) with mucous membranes, damaged

tissues, or the blood stream. If not managed, HIV can develop into

Acquired Immunodeficiency Syndrome (AIDS). 

Return to What We Know

E-H

ecosystem

 - A group of organisms that are interdependent and the

environment they live in and depend on. They are made up of biotic (living)

and abiotic (nonliving) parts. For example, cows grazing on a pasture

reflects an ecosystem. It would include the cows and everything that

surrounds them, for example, the grass, water, and of course other

animals, like the cow birds, army worms, fire ants, soil microbes, and other

living things associated with the pasture. 

Return to Why It Matters

Glossary

I-S

selective breeding 

– human-performed practice where two organisms of the

same species with desirable traits are bred together to produce offspring with

the desired traits. 

Return to Why It Matters

species

 - a group of living organisms consisting of similar individuals capable

of exchanging genes or interbreeding. 

Return to Why It Matters

sustainable

 – able to be maintained at a certain rate or level. 

Return to Why

It Matters

pesticide 

- substances used to kill, repel, or control organisms harmful to

cultivated plants or to animals (pests), including insecticides, herbicides,

rodenticides, bactericides/disinfectants, fungicides, and larvicides. Most are

also toxic to humans and animals. 

Return to Why It Matters

malaria 

– an intermittent fever with fluctuations in temperature caused by

a protozoan parasite (

Plasmodium

) carried by mosquitoes. The parasite

invades red blood cells and release toxic substances upon lysing. 

Return to

What We Know

invasive species 

– any species of organism not native to a specific location

that has been brought there and has a tendency to cause harm to the

ecosystem. 

Return to What We Know