Vital
Systems
Ecosystems are the arena in which
life flourishes on this planet. The relationships
between organisms of any kind and the physical elements
around them reach a state of equilibrium within these
systems, allowing life to sustain itself over time.
But this balance can be disrupted, and is occurring
increasingly often here on Earth.
As far as definitions
go, ecosystems are the connections that are established
between living entities and the physical medium in
a determined location. But an ecosystem can have a
broad scope: the largest of all is our planet, and
the smallest… it could be the tiny drop of water that
is home to microorganisms.
Within an ecosystem, living organisms
interact with the existing physical components: light,
temperature, water, soil, and with each other.
The forest is used most often
to represent an ecosystem, and the degradation that
occurs when trees are cut down provides a clear example
of the impacts of human tampering.
Late last year, the Washington-based
World Resources Institute (WRI) and the United Nations
Environment Program (UNEP) presented a disturbing
report on the health of the world's ecosystems,
showing that they are deteriorating at an alarming
rate.
''Every measure used by scientists
to assess the health of the world's ecosystems tells
us that we are drawing on them more than ever and
degrading them at an accelerating pace,'' stressed
Klaus Töpfer, UNEP executive director.
''We depend on ecosystems to
sustain us, and their continued good health depends,
in turn, on how we take care of them,'' he stated.
People
and Ecosystems - A Report by the World Resources Institute
Tierramérica:
What is an ecosystem?
What
is a Biome?
The
World's Biomes
WildWorld:
Eco-regions of the world - National Geographic
Sustenance
of Humanity
Agriculture is seen as the key
to understanding the beginning of human civilizations.
Everything started during that mysterious and immense
time we now call pre-history, when our very distant
ancestors domesticated certain plant species for the
first time. This
is believed to have taken place some 14,000 years
ago.
The emergence of agriculture
had a major impact on humanity: people could now control
- to a large extent - the availability of food. The
consequences of this "discovery" were astounding.
For one, the first human settlements appeared because
nomadic hunter-gatherers turned into sedentary farmers.
Agricultural activity dominated
economies for thousands of years - until the industrial
revolution. But the importance of farming did not
diminish as factories were built, or with the arrival
of the digital age. After all, it is a question of
producing food. And without food, life is impossible.
On the Internet, there is intense
traffic as far as information on agricultural issues,
which is reflected in the number of portals
and search
engines dedicated to this topic.
The worldwide web provides an
arena for discussions about agriculture's new frontiers:
the impact of biotechnology, the pros and cons of
genetically modified crops, the problems created by
soil erosion, the promotion of urban agriculture,
and, of course, the need for more
ecologically-sound agricultural practices.
Ecological, sustainable, organic
or conservation
farming has to do with the responsible use of soils.
It is an attempt to prevent the degradation of the
land in order to ensure that future generations can
continue to reap its rewards.
A good place to start your agriculture-related
Internet navigation is the United
Nations Food and Agriculture Organization (FAO),
which has created a mega-portal. The FAO's efforts
are based on a critical observation: despite the advances
made in agriculture, today there are at least 800
million people in the world who suffer from the lack
of food.
FAO
Homepage
FAO:
What is conservation agriculture?
History
of Farming in the USA
Yahoo!:
Agriculture Directory
Agrisurf:
Specialized Website
Amphibians
with Tails
Salamanders are often confused
with lizards, as their sinuous profile tends to evoke
the idea of a reptile. But don't let yourself be fooled:
they are definitely a part of the surprising and numerous
family of beings with a ''double life'' - those who
live in the water and on land - reflected in the Greek-based
adjective amphibious.
There are some 300 varieties
of salamanders, but all are defined by the name of
their order: Caudata,
''with tail.'' Study of these creatures forms part
of herpetology,
which targets reptiles and amphibians, and their scientific
classification encompasses 10 different families.
The Internet is not immune to
the charm of salamanders, whose skins sport fantastic
natural designs. There are numerous directories
and links in cyberspace showing off the different
varieties: tiger-stripes, spotted, marbled, or the
common 'Salamandra salamandra,' known as the newt.
There is also a great deal of information about another
mysterious being that can be confused with a salamander:
the 'axolotl'
or the Ambystoma mexicanum.
What is the motive of this cyberspace
dedication to salamanders? Beyond the frontiers of
science, many members of the order Caudata are treasured
as pets.
Salamanders are fascinating because
of their colors, their strange shapes, and the incredible
speed with which they eat. But also because they reflect
an important part of the Earth's history.
Scientists affirm that salamanders
are descendants of the first vertebrates to come out
of the water when life was - from the perspective
of today's humans - still being formed. And the oldest
fossils of the Caudata date back 150 million years
- the middle of the Jurassic period…
Caudata:
Classification of the salamander
Newts
and salamanders
Salamanders
in Yahoo!
Photos
of salamanders
North
American Herpetology
Links
to salamander sites
How
salamanders eat
Vital
Element
Water is life. A truth so basic
that it is commonplace. Concern about the scarcity
of this ''vital element'' is widespread, as many people
believe that water will be the detonator of future
wars.
These concerns also inundate
the Internet. It is not by accident, of course. We
already know that life itself originated in water,
that water covers three-fourths of the Earth's
surface, and that 80 percent of our
bodies is simply water.
But the problem with freshwater
is perfectly easy to understand: 97.5 percent of the
water on Earth is salty, and three-fourths of the
remaining 2.5 percent are frozen around the North
and South Poles. What is left is just 0.01 percent
of this precious resource.
Even so, there is the broad impression
that this is enough to supply a very large population.
But the truth is that freshwater is not well distributed
throughout the world, and in many places it is threatened
by problems of contamination, squandering and poor
infrastructure, as occurs with the dams that affect
the basins of some major
rivers.
The standpoint of water scarcity
has generated a global mobilization, which has as
its axis the United
Nations. During the first Earth Summit, in Rio
de Janeiro in 1992, freshwater comprised an entire
chapter in the program of action known as Agenda
21. World
Water Day is now an annual event, and currently
the UN is preparing a global
report on the availability of this life-giving
resource.
UNEP:
Freshwater - Resources - Agenda 21
UNESCO:
World Water Day
Agenda
21: Chapter 18 on Water
The
world's largest rivers
24
UN agencies prepare a global report on water
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