Endangered Species 

In biology and ecology, extinction is the cessation of existence of a species or group of taxa, reducing biodiversity. The moment of extinction is generally considered to be the death of the last individual of that species.

More than 90 percent of all organisms that have ever lived on Earth are extinct. As new species evolve to fit ever changing ecological niches, older species fade away. But the rate of extinction is far from constant. At least a handful of times in the last 500 million years, 50 to more than 90 percent of all species on Earth have disappeared in a geological blink of the eye.

Mass Extinctions

Cretaceous-Tertiary extinction, about 65 million years ago, probably caused or aggravated by impact of several-mile-wide asteroid that created the Chicxulub crater now hidden on the Yucatan Peninsula and beneath the Gulf of Mexico. Some argue for other causes, including gradual climate change or flood-like volcanic eruptions of basalt lava from Indias Deccan Traps. The extinction killed 16 percent of marine families, 47 percent of marine genera (the classification above species) and 18 percent of land vertebrate families, including the dinosaurs.

End Triassic extinction, roughly 199 million to 214 million years ago, most likely caused by massive floods of lava erupting from the central Atlantic magmatic province -- an event that triggered the opening of the Atlantic Ocean. The volcanism may have led to deadly global warming. Rocks from the eruptions now are found in the eastern United States, eastern Brazil, North Africa and Spain. The death toll: 22 percent of marine families, 52 percent of marine genera. Vertebrate deaths are unclear.

Permian-Triassic extinction, about 251 million years ago. Many scientists suspect a comet or asteroid impact, although direct evidence has not been found. Others believe the cause was flood volcanism from the Siberian Traps and related loss of oxygen in the seas. Still others believe the impact triggered the volcanism and also may have done so during the Cretaceous-Tertiary extinction. The Permian-Triassic catastrophe was Earths worst mass extinction, killing 95 percent of all species, 53 percent of marine families, 84 percent of marine genera and an estimated 70 percent of land species such as plants, insects and vertebrate animals.

Late Devonian extinction, about 364 million years ago, cause unknown. It killed 22 percent of marine families and 57 percent of marine genera. Erwin said little is known about land organisms at the time.

Ordovician-Silurian extinction, about 439 million years ago, caused by a drop in sea levels as glaciers formed, then by rising sea levels as glaciers melted. The toll: 25 percent of marine families and 60 percent of marine genera.

There are now 41,415 species on the IUCN Red List and 16,306 of them are threatened with extinction, up from 16,118 last year. The total number of extinct species has reached 785 and a further 65 are only found in captivity or in cultivation.

Estimates of global species diversity have varied from 2 million to 100 million species, with a best estimate of somewhere near 10 million, and only 1.75 million known species of living organisms on earth have been identified.

The biological impoverishment of the Earth is accelerating as human population grows. The share of bird, mammal, and fish species that are now in danger of extinction is in double digits - 11 percent of all bird species, 25 percent of mammals, and 34 percent of fish. Over 19,000 plant species and 5000 animal species are classified as endangered.

99% of threatened species are at risk from human activities.

Rainforests are home to 50 to 70% of all life forms on Earth. Coral Reefs and the Oceans are home to 25% to 30% of all life forms. At the current rate of destruction how long will it be before human beings become endangered?

Scientists estimate an average of 137 species of life forms are driven into extinction every day for a total of 50,000 each year.

Endangered Species

  Many species are being put at risk of extinction on a daily basis

 The threats to wildlife are:   

Poaching- Many animals are hunted and killed for their body parts to be used for ornamental decoration as well as in superstitious potions. Currently, the demand for animal parts is centered in several parts of Asia where there is a strong market for traditional medicines made from items like tiger bone and rhino horn. Many animals are also killed for food ,this is referred to as bushmeat.

Tiger Skin 

 

Habitat Destruction- More and more land  is being claimed  by Man for his own ends. Centuries may be required to bring back a forest that was cut down or burnt out in the space of a few years. Many of the world's severely threatened animals and plants live in such forests, and it is certain that huge numbers of them will disappear if present rates of forest loss continue.

Rainforest Burning

 

Pollution-Chemicals and toxins that Man is releasing into the air and water causes an imbalance in ecosystems. Contamination of air, water, or soil by the discharge of harmful substances contribute to species extinction.

Polluted Water

 

Global Warming- The change in temperature and climate is affecting species that dwell on land as well as the ocean. Concern is growing that atmospheric changes could bring on rapid, profound climatic changes. A slight rise in maximum water temperatures - only one to two degrees can cause coral bleaching.

A slight rise in temperature can bleach coral like this

 

Introduction of Exotic Species-Species that "belong" to an area are said to be native species. Exotic Species are interlopers, foreign elements introduced intentionally or accidentally into new settings through human activities. Exotics may seriously disrupt delicate ecological balances and create a cascade of unintended consequences.

 

Top Endangered Species

16 May 2007

According to the World Wildlife Federation (WWF) the most endangered species are:

  • Spiny dogfish - Spiny dogfish is a slender, smaller sized white-spotted shark that grows to about one metre long and travels in schools. It is found in cool, coastal waters worldwide. Known as rock salmon, it is used in fish and chips in the UK and as a smoked meat delicacy in Germany, called Schillerlocken. 

Spiny dogfish

  • Sawfish - Populations of the seven species of sawfish have drastically declined. They are traded as live animals for public aquariums, and also for their fins and meat. Their distinctive saw-like snouts are sold as souvenirs and ceremonial weapons, while other body parts are used for traditional medicines. 

Sawfish

  • Tigers - In addition to continuing threats from habitat loss and forest conversion, an old threat is about to re-emerge in China, which could put the last remaining tigers further at risk - the potential re-opening of trade from tiger 'farms'. 

  • Asian rhinos - Historically hunted for their horn, a prized ingredient in traditional Asian medicines, and devastated by the destruction of their lowland forest habitat, Asian rhino populations are now distressingly small. An upsurge in poaching over the last few is taking its toll even on populations that were thought to be stable. 

  • Red and pink coral - A jewel that comes from reefs and atolls, it is the most valuable of all the precious corals. Pink coral has been fished for over 5,000 years and used for jewellery and decoration. Over-harvesting and the destruction of entire colonies by bottom trawls and dredges have led to dramatic population declines. 

  • European eel - The European eel comes from coastal and freshwater ecosystems throughout Europe, including Mediterranean countries. Stocks have declined dramatically over the past several decades due to overfishing and poaching. There is significant international demand for this species, both for live juvenile eels (shipped from Europe to Asia) for rearing in aquaculture and for the highly valued meat of adults. 

European eel

  • Elephants - The ongoing poaching of elephants and illegal international trade in ivory is stimulated by rampant ivory sales in some countries, particularly in Africa and Asia. Despite previous CITES decisions, and valiant efforts of some countries, these markets persist. The time has come to put political will behind serious efforts to close down these illegal and unregulated ivory markets, the true driver of elephant poaching.

  • Great apes - Wild populations of great apes (gorillas, bonobos, chimpanzees and orangutans), continue to decline drastically and are threatened by the combined effects of illegal trade in live animals (usually for pets), poaching for meat, disease and habitat disturbance, fragmentation and destruction. 

Chimpanzee shaking his head
Chimpanzees just don't understand how humans can be so careless

  • Cetaceans-Seven out of the 13 great whale species are still endangered or vulnerable after decades of protection. Facing a multitude of hazards Whales, dolphins and porpoises are succumbing to new and ever-increasing dangers. Collisions with ships and entanglement in fishing gear threaten the North Atlantic right whale with extinction, while the Critically Endangered Western North Pacific gray whale is at serious risk because of intensive oil and gas development in its feeding grounds. Alarm is also growing over other hazards including toxic contamination, the effects of climate change and habitat degradation. It's illegal, but it still happens: commercial whaling Despite a moratorium on commercial whaling and the declaration of virtually the whole of the Southern Ocean as a whale sanctuary, each year over 1,000 whales are killed for the commercial market.

Cetaceans

  • Bigleaf mahogany - This highly valuable South and Central American rainforest tree species was listed in CITES Appendix II in 2002, in response to population declines and high levels of illegal logging and trade. Only one country still exports large commercial quantities, Peru, and after five years, these problems continue, and concerted action is needed.

Bigleaf mahogany

 

Estimated Remaining Populations

Tigers 5,000 to 7,400
Orangutans 20-30,000
Chimpanzees 100,000
Gorillas 30,000-35,000 
Rhinos 14,000
Pandas 872 to 1352
Blue Whales 10,000
  • Frogs

    • New guidelines intended to guard amphibians against deadly fungus-Click Here

    • Amphibian Evolution in Losing Race With Environmental Change-Click Here

    • Popular weed killer demasculinizes frogs, disrupts their sexual development-Click here

    • Ultraviolet radiation can cause physical deformities in amphibians-Click Here

    •  

  • Pandas

  • Tigers

  • Whales

To Find Out More about Endangered Species Visit The Organizations Below



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