Several subspecies of lions and tigers have become extinct within written history.  Unless we take immediate and effective measures to prevent it, it will be only a matter of time till entire species begin to disappear.


Agriculture - Usually refers to farming, but it can also refer to timber harvesting.  Any activities that harness the energy of the sun for man's use through the growing of plants or the raising of animals.

Ecosystem - A complete, self-sustaining community of living things together with their environment.  A forest is an ecosystem, as is a large lake or a desert.  However Urban areas and agricultural areas created by man are not ecosystems, as they will gradually change into something else if left alone.

Environment - All of the conditions that affect living things.  The Serengeti Plains is a jackal's environment.  Your home town is your environment.  "The" environment refers to all the conditions that affect all living things everywhere, and it is often called the "Biosphere."

Extinction - The permanent loss of a species when the last member dies.

Habitat - The part of an environment that supplies the needs of a particular species.  Beetles living under a rotting log, hawks living in trees, and deer living in open grasslands may all share a woodland ecosystem but have separate habitats.  A habitat is sometimes called a "niche."

Predators - Animals that eat other animals to survive.  Hawks, leopards, and sharks are examples of predators.

Prey - Animals eaten by predators.  Deer, crows, and salmon are examples of prey.

Species - A group of living things that can interact to produce offspring like themselves.  Tigers do not have lion cubs, and an eagle and owl cannot interact to produce offspring like themselves.

Species Diversity - The number of different species living in a certain place.  Species diversity is naturally higher in the Amazon rainforest than it is in the Arctic tundra.  This does not refer to the number of individuals of a species.  Two thousand cattle in a pasture may show very low species diversity.  Two cows, two sheep, and two goats in the same pasture triple its species diversity.

Tasmanian Tiger - Not really a tiger (Panthera tigris) but a Thylacine (Thylacinus cynocephalus).  The Tasmanian tiger was a large, striped predator from Australia that was more closely related to the kangaroo than to the tiger.  It is sometimes called a Tasmanian wolf.

Urban Area - A place developed for humans to live or work.  The changes are usually great enough that many species once found in the area can no longer live there.


INTRODUCTION:  Extinction is the permanent loss of a species.  It has happened often throughout the history of life on Earth as new species out compete older ones and as environmental changes rewrite the rules of survival.  Many interesting species, such as Tyrannosaurus rex, have gone extinct and we might regret only knowing them by their fossil records.  Yet the truly regrettable extinctions are those which are not part of natural order.  The passenger pigeon and Tasmanian tiger did not give up their place for better species.  They were driven out by habitat destruction and man's uncontrolled use or abuse.

NATURAL SELECTION AND EXTINCTION:  A special relationship exists among the "three p's," predators, prey, and plants.  A sudden change in one of these things affects the other two.  The emergence of a faster prey species reduces the success rates of predators.  Fewer predators survive, the population of prey increases, and the supply of plants decreases.  Into this situation, the emergence of a faster predator is welcomed by an abundant supply of prey and the natural order is quickly restored.  There are a certain number of jobs in a given ecosystem.  The arrival of better equipped species usually results in another species becoming extinct.

ENVIRONMENT AND EXTINCTION:  Changes in temperature or rainfall may turn jungles into open grasslands or deserts into swamps.  Some animals are more open to change than others.  One type of bat found in Africa only gets its food from one particular species of flower.  If conditions were too poor for that flower to exist, the bat would die.  Coyotes use a large number of food sources.  They are less likely to suffer from the loss of a single prey species.

UNNATURAL EXTINCTION:  This is the type of extinction you frequently hear about in the news.  Unnatural extinction is not part of a process of gradual improvement.  It is the result of habitat destruction and mankind's misguided attempts to use or exterminate other species.  The rate of extinction is now 1000 times faster than it used to be, but the emergence of new species goes on at the same rate.  This causes an imbalance resulting in a reduction of the total number of species, something we call a lack of diversity.  An ecosystem that lacks diversity is less able to handle changes.  A large number of jobs are being performed by a few species, and a single natural disaster could crash the entire order.

WHY MAN CAUSES EXTINCTION:  Some animals are harvested for their fur, feathers, or other parts.  Other animals are killed because they conflict with human uses of land.  Yet a large number of species disappear simply because their homes disappear as land is changed from its natural state for urban and agricultural use.  Unless man balances his own need with the needs of other species, the rate of extinction will continue to rise.

UNNATURAL EXTINCTION CAN BE STOPPED:  It is not beyond our power to stop the dramatic loss of species, but it will take some work and a change in our attitude toward nature.  When the welfare of other species is important to us, slowing the extinction rate will be mostly common sense.  Wildlife and habitat values will become part of our decision making and turn human "progress" into the good thing it was meant to be rather than just another term for "exploitation."  It is a matter of changing our lifestyle to make room for all living things.

WHY WE MUST STOP UNNATURAL EXTINCTION:  There are many of reasons why.  You may not agree with all of them, but there are enough reasons to convince anyone who is willing to take the problem seriously.  First there is the moral reason--that destroying a species for man's pleasure or convenience violates rules of behavior that we were meant to follow.  Most religious traditions say all life on earth is the result of forces greater and wiser than man, and if this is so, unnatural extinction is a crime against those forces.  Then there is the practical reason--that an entire world whose species diversity is as poor as it is in your back yard cannot sustain life as we know it.  Without the contributions to our global environment made by truly wild areas, our urban and agricultural areas cannot sustain the demands we place on our limited planet.  Some people may argue that this is not so, but there is only one way to find out.  By the time you could prove the planet is dying, it would be too late to save it.  And if it were possible to live in a world without tigers, without rainforests, without lions and giraffes and pronghorns, we must confront the last reason: would you be happy there?  Would your children be content with movies of lions and photos of antelopes?

CAN WE UNDO THE EFFECTS OF EXTINCTION:  No.  Currently there are scientists trying to bring back the Tasmanian Tiger from samples of DNA.  If they succeed, there will be no parents to pass on skills to these offspring, so even with living animals we have not completely undone extinction.  It is wrong to think technology by itself can bring back what we have lost.  The only rational course of action is to change our behavior and shift our priorities.  We spend millions of dollars each year trying to find other life in the universe.  Meanwhile every year sees the disappearance of several species, some of which we never knew existed.  Learn what you can do to bring about change and take care of your home planet.