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Inhabitants of the Water

When we think about fish, we always imagine water too, their natural world. Fish have inhabited water nearly since life began on Earth, when the evolutionary process was initiated that has led to an enormous family: 20,000 to 30,000 different species of fish have been recorded.

The Encyclopedia Britannica defines fish as ''any of a variety of cold-blooded vertebrate animals (phylum Chordata) found in the fresh and salt waters of the world.''

Any journey through the Internet's world of fish found quickly reveals the meaning of ''ichthyology'': the science dedicated to the study of these cold-blooded aquatic vertebrates. The cyber-excursion also allows the traveler to explore the worlds of scientific classifications, glossaries, collections, digital aquariums, and even mythology.

Fish constitute an essential part of life on this planet, and they are key to the aquatic ecosystems that cover more than three-quarters of the Earth's surface. As far as their connection to humans, fish provide an important source of protein, though over-exploitation of this natural resource has caused profound distortions in the environment.

Following is a guide for beginning your navigation through the watery world of fish:

Encyclopedia Britannica: Fish
Australian Museum: Fish
More than 100 Aquariums on Yahoo!
Fish: Frequently Asked Questions
List of Fish Species

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

 


 

Copyright © 2001 Tierramérica. Todos los Derechos Reservados

 

 

Angel Fish in the Caribbean Sea. Credit: Claudio Contreras
 Angel Fish in the Caribbean Sea. Credit: Claudio Contreras

 

 

 

 

 

 

 

 

 

 

 

Edible fish in Caribbean coral ref. Credit: Claudio Contreras
 Edible fish in Caribbean coral ref. Credit: Claudio Contreras

 

 

 

 

 

 

 

 

 

 

 

Man plowing in Santa María del Cobre, Michoacán state, Mexico. / Credit:  Claudio Contreras
  Man plowing in Santa María del Cobre, Michoacán state, Mexico. / Credit: Claudio Contreras