Some cool animals that are extinct images:
December 2011 Specimen of the Month: Rocky Mountain Locust
Image by wagnerfreeinstitute
We have a number of specimens that are now extinct in our natural history collection, one of them being the Rocky Mountain Locust (Melanoplus spretus). Unfortunately, our specimens were damaged by a dermestid beetle infestation and only the abdomens remain. These scanty remains may not look impressive, but the abdomens contain the sex organs, making them valuable for research. We chose to highlight this specimen because it has an amazing story to tell.
The Rocky Mountain Locust is the historic culprit notorious for decimating agriculture in the Midwest in the 1800s. It ranged from Canada to the Mexican border and from the Sierra Nevadas to the Mississippi River. They formed plagues which migrated, wiping out entire fields of crops in a matter of hours. In 1875 Rocky Mountain Locust swarms hit epic proportions with an estimated 12.5 trillion locusts forming a 110-mile wide, 1800-mile-long swarm, a black cloud that eclipsed the sun for five days as it passed overhead. Eating everything in their path, (even the clothes people were wearing!) the plagues threatened thousands of settlers with starvation and congress called them “the greatest impediment to settlement of the West.” For reasons not completely understood, this species, which formed the greatest animal mass ever recorded on our continent, disappeared a few years later. The last Rocky Mountain Locust ever seen was captured in 1902.
It is thought that while they had an enormous range, the Rocky Mountain Locust had a comparatively small breeding ground restricted to sandy riverbanks in a small number of valleys in the Midwest. Farmers planting crops in these valleys upturned the soil, killing the eggs and, unknowingly, exterminated the species. There are undoubtedly other factors involved. There may have also been a lack of genetic variation, making the species vulnerable, but research is difficult because of the scarcity of specimens; people neglected to collect them because they were so prevalent. Researchers today are finding specimens preserved in glaciers in Montana and Wyoming.
The Rocky Mountain Locust specimens in the Wagner collection were donated by Charles Johnson (1863-1932), naturalist and specialist in entomology and malacology. He was the curator of the Wagner Free Institute of Science from 1888 to 1903 and authored many of the hand-written labels and drawn diagrams still on view in the Exhibit Hall, including those of the Rocky Mountain Locust. The specimens were originally collected in West Point Nebraska by Lawrence Bruner (1856-1937). He wrote many books on entomology and agriculture, including the report The Rocky Mountain Locust for the third report of the United States Entomological Commission.
the sixth extinction?
Image by B.S. Wise
Illustrated by Dorothy Lathrop from
"Fierce-Face: The story of a tiger" by Dhan Gopal Mukerji (1936)
The forthcoming book: The Sixth Extinction by Elizabeth Kolbert examines the role of humans in the eradication of species.
Is man on course to cause the sixth extinction?
"...Kolbert is to focus on humanity's impact on the animal world, and in particular will look at the species that are today being rendered extinct by men and women. Scientists say the number of species being lost is approaching levels reached during five pivotal extinction events that have swept the planet over the past 600 million years. Among these catastrophes was the event that wiped out the dinosaurs 65 million years ago. Kolbert's task will to be show whether or not humanity – with its spiralling population, widespread habitat destruction, over-fishing and global warming – is rivalling these.
...In 1996 the distinguished palaeontologist Richard Leakey, with journalist Roger Lewin, produced his version of The Sixth Extinction, in which he argued that the five previous mass extinction events were now being matched by a sixth. "Homo sapiens is poised to become the greatest catastrophic agent since a giant asteroid collided with the Earth 65 million years ago, wiping out half the world's species in a geological instant," he says.
Other distinguished scientists, including EO Wilson and Norman Myers, have also produced works on this theme...
...A succession of reports from United Nations wildlife experts and climate scientists have shown that our planet is in peril and that thousands of species are now hovering on the brink of extinction....
...The question is: what forces are responsible for the loss of vast numbers of species in such a short period?
Answers depend on individual cases, it transpires. For example, a huge asteroid crashing on Earth 65 million years ago is generally thought to have done for the dinosaurs. The vast plume thrown up by the impact coated the planet in dust and triggered a devastating climate change. As a result, 47% of marine genera (groups of related species) and 18% of land vertebrate families, including the dinosaurs, were wiped out.
And as evidence geologists point to the Chicxulub crater near the Yucatán peninsula, beneath the Gulf of Mexico, as the impact point of the asteroid.
Similarly the Triassic extinction, which occurred between 199 million and 214 million years ago, was most likely caused by massive floods of lava erupting from the Atlantic Ocean. These created a wave of global warming. In this case, around 22% of marine families and 52% of marine genera were eradicated.
Then there was the Permian-Triassic extinction, about 250 million years ago, which has been linked to both asteroid impacts and volcanism. This was Earth's worst mass extinction, killing 95% of all species, including an estimated 70% of land species such as plants, insects and vertebrate animals. Before that, the Late Devonian extinction, about 360 million years ago, killed 57% of marine genera. Its cause remains unknown. And finally, there was the Ordovician-Silurian extinction, about 440 million years ago, which has been linked with changes in sea levels and which led to the eradication of 60% of marine genera.
Life on Earth has, on some occasions, become remarkably unpleasant in a short space of time, to say the least – though this has not always been the prevailing view among scientists. In fact, Darwin thought extinction was a slow, painful business. "The complete extinction of the species of a group is generally a slower process than their production," he once remarked, a view that held sway for more than a century. Indeed it was only in the latter half of the 20th century that scientists uncovered evidence – the Chicxulub crater – that an asteroid crash must have been involved in the demise of dinosaurs. Extinctions could be sudden, they realised....
...On top of volcanoes and errant astronomical objects, other factors involved in these mass extinctions include extreme ice ages which coated the planet in ice from pole to equator, and eruptions of deep-sea methane deposits that set off massive global warming. The resulting death toll is measured in millions of species.
What remains unclear is the degree to which humans are now repeating this bloodletting, to the extent that we are about to set off a sixth extinction wave. If so, we will be the first single, biological cause of this kind of catastrophe. "If you add up the numbers of species that have been wiped out over the past few hundred years, then you find the figures fall well short of a mass extinction," said MacLeod. "It is only when you look at the numbers of creatures that are poised at the brink of eradication does the picture become alarming."
Tigers, coral reefs and all the marine life they support, amphibians such as the golden frog of Panama, orang-utans, sharks, mountain gorillas, the marine iguanas of the Galápagos, albatrosses, chimpanzees and thousands of other creatures now face obliteration: hunted, rendered homeless, and poisoned by humans.
More to the point, this predation has been going on, not for hundreds of years, but for tens of thousands of years.
Whenever Homo sapiens has moved into new territory, this has been followed quickly by the disappearance of most large land mammals, palaeontologists have found. For example, the Clovis people, ancient hunters armed with fearsome stone-tipped spears, arrived in North America 12,000 years ago.
A total of 75 species, including woolly mammoths, mastodons, four-horned antelopes and lumbering sloths the size of giraffes were killed off almost immediately. A thousand years later, the slaughter continued in South America when humans arrived there.
The glyptodon (a giant armadillo-like animal), several species of rodent and various llama-like animals were wiped out. And a similar bloodbath occurred in Australia with the arrival of the first members of Homo sapiens.
In short, humanity has a great deal of blood on its hands, spears and guns. Whether we maintain this kind of eradication of our fellow Earthlings remains to be seen. Most experts predict grim times, an outcome that will provide Kolbert with the core of her ambitious look at the fate of our planet – and at the fate of the animals who are trying, unsuccessfully, to share it with human beings."
(exerpted from an article by Robin McKie, The Observer, Sunday 8 November 2009)
read the whole article here
