Biology Ch 18 Review: The Environment. Global Change: Review A cid rain: Coal burning power plants send smoke high into the atmosphere through tall smoke

Biology Ch 18 Review: The Environment

The Environment

Global Change: Review

Acid rain: Coal burning power plants send smoke

high into the atmosphere through tall smoke stacks.

This smoke contains high concentrations of sulfur because the coal that the plants burn is rich in sulfur.

Scientists have since discovered that the sulfur can combine with water vapor to produce sulfuric acid.

Rain and snow carry the sulfuric acid back to Earth’s surface.


This acidic rain raises the pH level in lakes and ponds, killing off all life.

It kills forest on which it falls , burning the trees and anything else it falls on.

Acid rain even dissolves the faces on stone statues that have stood unmoving for centuries in cities all over the world.


CFCs and the ozone layer:

In recent years, scientists have discovered that the Earth’s ozone layer was being damaged by chlorofluorocarbons (CFCs). CFCs commonly used as refrigerants in air conditioners, refrigerators and as a propellant in aerosol sprays.

The result of this damage became apparent when scientists noticed a hole forming in the ozone layer over Antarctica. This hole was allowing increased radiation into the atmosphere which could be cancer causing.

Today, CFCs have been banned in almost all corners of the world and the damage to the ozone layer has slowly been repairing itself once nations agreed to suspend their use.


Another major environmental issue in recent years has been global warming.

An increase in carbon dioxide; a byproduct of modern industry, has been trapping the heat from the sun in the atmosphere (The greenhouse Effect), slowly raising the Earth’s average temperatures year after year for the past few hundred years.

As the Earth’s temperatures rise, many affects may be felt.


Global warming:

The most pronounced affect will be the melting of the polar ice caps.

Scientists predict that melting ice could raise the world’s oceans substantially over the next 50 years if temperatures continue to rise at the current rates.

Today, scientists from countries all over the world are banding together to convince governments of the importance of signing treaties to limit production of Greenhouse gases.


Chemical Pollution:

One major environmental problem that impacts us on a local level is chemical pollution. Until recently people assumed that the environment could absorb any amount of pollution.

Chemical pollution from chemical spills, accidents, pesticide runoff from agriculture, and leaky storage containers have sent much hazardous chemical material into the environment.


Biological Magnification:

These chemicals accumulate in the fatty tissue of animals. As these molecules pass up through the trophic levels of the food chain, they become increasingly concentrated. This process is called biological magnification.

The danger with biological magnification is that these chemicals work up the food chain until they are in the fish that we ourselves get from our local food stores.


Nonreplaceable Resources:

Three nonreplaceable resources are being consumed or destroyed (going extinct) at a rapid rate.

These resources that are in danger are Species of living organisms are

becoming extinct

Fertile topsoil is being destroyed or washed out to sea

Ground water in aquifers is being used up or polluted

US endangered species


Nonreplaceable Resources: Extinction of Species

Today, perhaps some 10 percent of all species teeter on the brink of extinction.

Worst-case estimates hold that perhaps we may loose up to one-fifth the world’s species of plants and animals; about 1 million species, during the next 50 years.

An extinction of this size has not occurred in at least 65 million years, since the end of the age of dinosaurs.

The tragedy is that as these species go extinct, so vanishes our chances to learn about them and any possible benefits these species may hold for us.


Nonreplaceable Resources: Loss of Topsoil

Turning over the soil to eliminate weeds, allowing animals to overgraze ranges and pastures, and practicing poor land management all permit wind and rain to remove more and more of the topsoil.

Since 1950, the world has lost one-third of it’s topsoil, primarily because of human activity.



The Midwestern farm belt sits astride what was once a great prairie.

The topsoil of that ecosystem accumulated slowly as the remains of countless animals and plants decayed to form it.

By the time humans came to plough the prairie, the topsoil was more than a meter thick.



A third resource we can not replace is ground water. Much ground water is stored within porous rock reservoirs underground called aquifers.

In most areas of the United States there is very little effort being made to conserve ground water. Consequently, a large portion of it is wasted on watering lawns, washing cars, through leaky and inefficient faucets and toilets.

http://geoscape.nrcan.gc.ca/h2o/bowen/images/groundwater_e.jpg


Rapid Population Growth:

By about 2000 years ago, there were an estimated 130 million people on Earth. By 1650, the world’s population had reached 500 million.

The world’s population exceeded 6 billion in October 1999 and the annual increase is now about 94 million people

Population growth is fastest in developing countries of Asia, Africa, and Latin America. It is slowest in the industrialized countries of North America, Europe, Japan, and in New Zealand.


Rapid Population Growth:

Population growth tends to be highest in the poorest countries that can least afford it. Overpopulation hits hardest in third world countries in Africa and crowded poor areas such as Bangladesh and India.

At present, no one knows if the Earth will be able to support 6 billion people let alone the 9 billion projected by 2050.

Building a sustainable future is the most important task we as a world face in our present day.


CFCs, dioxins, and asbestos:

As you have seen, environmental problems affect all inhabitants of an ecosystem without regard to state or national boundaries.

International agreements to stop CFC production is one example of a step forward.

DDT and carcinogenic (cancer causing) substances such as asbestos and dioxins have been restricted in the United States and laws have been enforced to remove these materials from public environments.


Solving Environmental problems: Different Approaches

Two effective approaches have been taken to reduce pollution in the United States.

The first approach has been to pass laws forbidding it.

In the last 30 years, laws have begun to set strict standards for what can be released into the environment.

Many smokestacks now have mandatedAntipollution scrubbers installed

All cars now have catalytic convertors to reduce emissions


Solving Environmental problems:

A second effective approach to reducing pollution is to make it more expensive by placing a tax on it.

The gasoline tax is an example of such a tax.

By adjusting the tax, the government attempts to balance the conflicting demands of environmental safety with economic growth.

Gasoline Tax1921-Enacted at 1 cent per gallon1924-Increased to 2 cents1929-Increased to 3 cents1931-Increased to 4 cents1933-Increased to 5 cents1949-Increased to 6.5 cents1961-Increased to 7.5 cents1967-Increased to 9 cents1977-Increased to 11 cents1979-Increased to 12 cents1981-Increased to 13.5 cents1982-Decreased to 12 cents1983-Increased to 16 cents1984-Increased to 18 cents1990-Increased to 22 cents1991-Increased to 23 cents2003-Increased to 28 cents2005-Increased to 31 cents2006-Increased to 34 cents2007-Increased to 36 cents2008-Increased to 37.5 cents


Solving Environmental problems:

Many of the world’s environmental problems can be solved if seriously addressed by both politicians and the public.

A combination of scientific investigation and public action can be a powerful combination to solve many of these problems.

The most important aspect is our own role as consumers. We, as a society, need to learn to all do our part so, as a whole, we can reduce energy usage and conserve the resources we currently have.

Among Simpson’s best known projects is Hudson River Purge. This installation in New York is part of a continuing series, dating back to 1983. Simpson placed soft limestone disks in the headwaters of the Hudson River (part of the New York City water supply).

Each limestone tablet weighed 50 lbs . This material had a pH level that allowed it to help neutralize the acidic waters of the Hudson where it was placed. Like Simpson’s previous River Rolaids, the sculpture acts both as a pun on cleaning up the river’s indigestion from man-made pollutants, and as an actual release of a large amount of natural chemicals designed to help neutralize the acidic waters of the polluted zone.

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Biology Ch 18 Review: The Environment. Global Change: Review A cid rain: Coal burning power plants send smoke high into the atmosphere through tall smoke