Gourt > Science > Biology > Ecology > Ecosystems (19)
In ecology, an ecosystem is a combination of all the living and non-living elements of an area. Ecosystems are the smallest level of organization in nature that incorporates both living and nonliving factors. They can range in scale from a wide geographical area such as the Sahara Desert to something small as a puddle. The term microecosystem may be used to describe a very small (often closed) ecosystem.
In general terms an ecological system can be thought of as an assemblage of organisms (plant, animal and other living organisms—also referred to as a biotic community or biocoenosis) living together with their environment (or biotope), functioning as a loose unit. That is, a dynamic and complex whole, interacting as an "ecological unit."
Early conceptions of this unit showed a structured functional unit in equilibrium of energy and matter flows between its constituent elements. Others considered this vision limited, and preferred to understand an ecosystem in terms of cybernetics. From this view an ecological system is a functional dynamic organization, or what was also called steady state. Steady state is understood as the phase of an ecological system's evolution when the organisms are "balanced" with each other and their environment. This balance is achieved through various types of interactions, such as predation, parasitism, mutualism, commensalism, competition, and amensalism. Introduction of new elements, whether abiotic or biotic, into an ecosystem tend to have a disruptive effect. In some cases, this can lead to ecological collapse and the death of many native species. The branch of ecology that gave rise to this view has become known as Systems Ecology. The abstract notion of ecological health attempts to measure the robustness and recovery capacity for an ecosystem; that is, how far the ecosystem is away from steady state.
More on [ Ecosystem ]
Long Term Ecological Research Network - LTER :: Research Centers
Ecosystem Biodiversity :: Biodiversity
Ecosystems and Habitats :: Conservation and Endangered Species
Reform Should Make Health the First Item of Business
The PLoS Medicine Editors argue that overcoming inequities and impediments to care in the US health care system will require directly addressing the prioritization of private profits over public health.
Vitamin K Supplementation in Postmenopausal Women with Osteopenia (ECKO Trial): A Randomized Controlled Trial
Angela Cheung and colleagues investigate whether vitamin K1 can prevent bone loss among postmenopausal women with osteopenia.
EurekAlert! - Biology
Study links nicotine with breast cancer growth and spread
Wed, 15 Oct 2008 00:00:00 -0400
(American Association for Cancer Research) A study published in Cancer Research, a journal of the American Association for Cancer Research, suggests a possible role for nicotine in breast tumor development and metastases.
Innovations in Pediatric Medicine CME conference brings together national pediatrics experts
Tue, 14 Oct 2008 00:00:00 -0400
(New York- Presbyterian Hospital/Columbia University Medical Center) In the last decade, biomedical and research breakthroughs, notably in genetics and stem cells, have helped transform the care of children, improving diagnosis and treatment for numerous diseases. On Nov. 8-9, Morgan Stanley Children's Hospital of NewYork-Presbyterian and Columbia University Medical Center will host a conference at the Grand Hyatt New York, titled "Innovations in Pediatric Medicine," to exchange the latest advances in genetics, stem cell therapy, and childhood disease treatment.
Penn State receives new NASA astrobiology grant
Tue, 14 Oct 2008 00:00:00 -0400
(Penn State) Developing strategies for finding life on other planets and in extreme environments on Earth will be the focus of Penn State's new astrobiology initiative under a five-year grant from NASA's Astrobiology Institute for "Signatures of Life from Earth and Beyond."
A Mysterious Journey - Rainforest, Desert, Grassland - Educational site about the 3 major biomes of the world, rainforest, desert and grassland.
Meta Description: [ Mysterious Journey is a Thinkquest 1999 Entry which focus on the 3 major biomes around the world: Rainforest, Desert and Grassland. We includes both photos and text in order to make our homepage informative. We also develop an interactive game - Treasure Hunt, which arouse visitor's interest in t... ]
Biodiversity and Mutualism in Ecosystems - Technical paper on the importance of biodiversity and mutualism (co-operation between different species) to ecosystem function and structural organization.
Meta Description: [ Paper: Importance of biodiversity and mutualism to ecosystem structure and function. Co-operative species networks; implications for modelling artificial systems; Permaculture. ]
Biomes - Living Worlds - Fact sheets, photos, and video clips on the climate, location, animal and plant adaptations, land formations, and human influences of seven major terrestrial biomes: tundra, taiga, temperate forest, grassland, chaparral, desert, and rainforest.
Meta Description: [ ThinkQuest is an international competition where student teams engage in collaborative, project-based learning to create educational websites. The winning entries form the ThinkQuest online library. ]
Ecological Society of America Panel on Vegetation Classification - Constituted by the Ecological Society of America to support and facilitate the creation of standardized, scientifically credible North American vegetation type classification.
Ecosystem Information - Information related to ecosystems in the Pacific and Yukon regions of Canada, including state of the environment reporting, environmental indicators, and programs and reports on ecosystem science, monitoring and research.
Meta Description: [ At this site you will find information related to ecosystems in the Pacific and
Yukon Region. This includes state of the environment reporting, environmental indicators, and programs and reports
on ecosystem science, monitoring and research. ]
Images of the Dry Tropics - Photographs of plants, animals, and landscapes from dry tropical habitats in the Americas, Africa, Madagascar, and Asia. Dry tropical habitat types include tropical dry forest, tropical deciduous forest, thorn forest, spiny desert, savannah, cerrado, and caatinga.
Len Webb Ecological Images Collection - Photographs by ecologist Len Webb depict a wide variety of native vegetation, fauna, landscapes, and soils, mainly in tropical and subtropical Northeastern Australia. Represents a wide range of ecosystem types.
Meta Description: [ Len Webb Ecological Images Collection ]
MBGnet - Descriptions and images of the biomes of the world, freshwater ecosystems, and marine ecosystems. From the Missouri Botanical Garden.
Meta Description: [ Answer the question: What's It Like Where You Live? Learn about terrestrial biomes and aquatic ecosystems. Follow link to site about plants. ]
Millennium Ecosystem Assessment - Reports from international effort to inventory global ecosystems, their contribution to human development, and the effect of the ongoing degradation of ecosystem services on human well-being.
Terrestrial Ecoregions of the World - Maps, descriptions, and index to 687 ecoregions across the globe. Javascript required.
The Buell-Small Succession Study - A long term old-field permanent-plot ecological succession study on the New Jersey Piedmont.
Meta Description: [ The Buell-Small Succession study:a long term old field permanent plot succession study on the New Jersey Piedmont. ]
The State of the Nation's Ecosystems - Online book about the current status and trends of the environment of the United States, aimed at public policy makers and concerned citizens.
The World's Biomes - Introduction to aquatic, desert, forest, grassland, and tundra biomes. School class project.
WorldBiomes - Covering five of the major world biomes.
WWF - Ecoregions - Detailed descriptions and images of the world's ecoregions. Javascript required.
Meta Description: [ Discover the world's ecoregions at World Wildlife Fund. Learn more about biological diversity and wildlife habitat management. ]
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