WHALING
LOSS OF BIODIVERSITY |
To understand why its loss is important, you must first know what biodiversity is. The generic definition is: the number of species in an environment and the number of individuals in each species. To put it simply, it is the number of different species in one area and the quantity of each of these species.
Newer definitions include
genetic variation within a species and variations between types of
biological communities on the earth. Functional
diversity is also now studied. This is an
analysis of the biological functions
performed by a specific ecosystem. This is useful in deter- mining the consequences of
human impact on an area. However, this is difficult to measure;
and it is highly possible that
important functions of an ecosystem may be overlooked in this measurement due
to our ignorance of the processes involved (Thorne-Miller and Catena 9).
The functioning of the biosphere (or our entire planet) is dependent on the combination of all existing ecosystems. Our very existence depends on this process functioning properly. Every organism has its niche in the environment. Once it is gone, it may not be able to be replaced by any other organism. What does this mean for us as humans? A whole host of things.
First, loss of diversity in an ecosystem can cause environmental changes. Loss of one species may cause a chain reaction, resulting in a change to the ecosystem itself. As we do not know what each specific organism contributes to its environment, we cannot predict how the ecosystem will be affected. The whole ecosystem may be weakened by this process.
Plants and animals produce defense mechanisms which are often chemicals used to either repel predators or to aid in elimination of their competition. These chemicals are vitally important to humans because many cures for human diseases have been found in these compounds. If a species is lost due to our interference in its ecosystem, we also lose the ability to study it for possible benefits to mankind.
Secondly, the loss of diversity gives us less choice as humans. This involves several areas. If certain species are lost, they are no longer available to us either as food, as enjoyment, or as resources for things we may not even know about yet. For example, if we deplete all the yellowfin tuna in the ocean, we no longer have this species available for our consumption. If we are divers or underwater explorers, we no longer can see this fish in its own environment and receive pleasure from this act.
The fewer animals left, the fewer we can see when we interact with nature.
Other problems with loss of diversity are more subtle. When a species is depleted so that there are only a few organisms left, the genetic diversity in the species becomes very low. This lowers the survival rate of the species. If all the individuals left are weak, have some form of abnormality, or are unable to survive in their environment, the species is doomed to extinction.
Extinction is a natural process that has occurred for millions of years. The problem is that the rate of extinction has increased dramatically in recent years due to our impact as humans. The rate of change is perhaps as damaging as the effects of the changes. There is no time for organisms to adapt to their constantly-changing environment.
One species may be necessary for the survival of another species. If an animal or plant is the main or only food source for another, its extinction will cause a domino effect. Other species will die out after the original one is lost.
The oceans of the world are much
more stable than the land. Changes here usually take a long time. The
organisms which live here have adapted to meet this slow, gradual change. They
cannot tolerate drastic, abrupt changes.
ECOSYSTEM DISRUPTION |
Loss of diversity in an ecosystem can cause
environmental changes. Loss of one species may cause a chain reaction,
resulting in a change to the ecosystem itself. Every organism has its niche in the
environment. Once it is gone, it may not be able to be replaced by any other
organism. As we do not know what each specific organism
contributes to its environment, we cannot predict how the ecosystem will be
affected. The whole ecosystem may be weakened by this process. |
| There are certain species which are known as
“keystone” species. These species have unusually important roles in their
ecosystems. Fluctuation in their population can cause dramatic effects on the entire system. In kelp ecosystems such as those off the coast of California there is a complex relationship between three keystone species: the sea otter, the sea urchin, and the kelp itself. If any one of these organisms declines severely in population, the whole ecosystem is changed. The otters keeps the urchin population in check. Without them, the urchins would devour the whole kelp forest. The kelp provides homes for many other organisms which would suffer if it was destroyed. Yet, without sufficient sea urchins, the sea otter population would decline. It is a complex web which must be balanced properly for the system to thrive (Thorne-Miller and Catena 24-25). |
KEYSTONE SPECIES |
MEDICINAL BENEFITS |
A second important consideration is that plants and animals produce defense mechanisms. These are often chemicals used to either repel predators or to aid in elimination of their competition. These chemicals are vitally important to humans because many cures for human diseases have been found in these compounds. If a species is lost due to our interference in its ecosystem, we also lose the ability to study it for possible benefits to mankind (see Terrestrial Ecosystems for more details). |
| An aspect not given much thought is that
the loss of diversity gives us less choice as humans. If certain species
are lost, they are no longer available to us either as food, as enjoyment, or as resources
for things we may not even know about yet. For example, if we deplete all the
yellowfin tuna in the ocean, we no longer have this species available
for our consumption. If we are divers or underwater
explorers, we no longer can see this fish in its own environment
and receive pleasure from this act. We also no longer have the ability to study this species to see how it interacts with other species in its ecosystem. |
LESS CHOICE |
Other problems with loss of diversity are more subtle.
When a species is depleted so that there are only a few organisms left, the genetic
diversity in the species becomes very low. All future offspring will
bear the genes of these few individuals. This lowers the survival rate of the
species by decreasing the chances of beneficial genes in the population. If all the
individuals left are weak, have some form of abnormality, or are unable to survive in
their environment, the species is doomed to extinction.
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WHALING |
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A hundred years ago a whaling ship could capture 35-40 whales in one three-year trip. Yet, in the 20th century at the peak of indus- trial whaling, the same amount of whales was processed in two weeks (Cousteau 215). This has caused the collapse of whale populations worldwide. Some are very near extinction. The International Whaling Commission has imposed limits on whale hunting, and some species are slowly recovering from our acts. However, as the species count rises again, countries are perched on the brink ready to lift the ban on whaling at the first moment that they possibly can. If this is done, our efforts will have been in vain for it will take very few years for us to be back in the same scenario where we found ourselves earlier this century. With more sophisticated technology like helicopters to track pods and floating factories to process the animals, the whales have little chance against our species. |
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ENVIRONMENTAL INDICATORS |
Another way our terrestrial systems aid humans is
that they can be forecasters of the future. When an ecosystem is
disrupted and other species begin to disappear or to have problems, we can
heed the warning. A classic example is the research done within the last few years
on amphibians. There has been a major decline in the populations of
frogs throughout the world, and of those which do survive many are
deformed. It is believed that because their skin is the mode through which
they respire, they are very susceptible to environ- mental changes. It is in our best interest to discover what is causing these problems before they seriously affect humans. |
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EXTINCTION: NATURAL VS. HUMAN-INDUCED
Extinction is a natural process that has occurred for millions of years so why does it deserve so much attention now? The problem is that the rate of extinction has increased dramatically in recent years due to our impact as humans. The rate of change is perhaps as damaging as the effects of the changes. There is no time for organisms to adapt to their constantly-changing environment. It is currently estimated that if current environmental practices are not changed, we may lose 50% of all species globally (Myers 131).
Extinction on such a scale may be catastrophic. In former large
extinctions in the earth’s history, it has taken millions of years for
the earth to recover. To put this in perspective, this is many times longer than
humans have actually been on the earth! The main difference now is that, instead of
having a mass extinction in one particular environment, we are losing huge numbers of
species in several key environments at the same time. Not only are we
depleting numerous animal and fish species, we are also depleting
large portions of our terrestrial plant species. With so many plant species
gone, there will be no resource base upon which to generate a recovery of animal species
– including humans (Myers 133). As we are also depleting nutrients
in our soil due to overuse,
what chance do the few remaining plant species have of sustaining life?
Refer to the Environmental Protection Agency website for
details on the Endangered Species Act and other environmental regulations. http://www.epa.gov/epahome
