extinction – bobmcgee

The snail’s tale …

National Public Radio, August 08, 2007 4:00 PM ET

It’s hard to prove conclusively that a species is extinct, but Gerlach says he’s all but certain that in the late 1990s, the last Aldabra banded snail curled up inside its purplish shell and died. In a paper in the journal Biology Letters, Gerlach lays the blame on an unusual series of summers so long and hot that they killed off all the younger snails.

“So the juveniles just weren’t surviving, and the adults gradually died off,” Gerlach says. “Now we don’t have juveniles or adults.”

Gerlach says he found the proof he needed in shells gathered up by collectors. Smaller shells, once common, disappeared with the frequent long, hot summers. He suspects — but cannot prove — that these bad summers are a side effect of global warming. If he’s right, then this snail has earned itself a grim distinction: It would be the first species in the modern era to become extinct as a direct result of climate change.

All but certain, that would be like 99.999%.

Saturday, Aug. 23, 2014 … Good News and a photo.

Cuvier’s Oplure …

The Anjajavy webpage burbles thus …

The forest sheltering rosewoods and baobabs is home to many animal species such as the famous Verreau lemur (Coquerel’s Sifaka), birds of paradise, the chameleon, the Cuvier oplure (a type of iguana)…

The range of Verraux’s Sifaka brings it nowhere near Anjajvy. It is reasonable to suppose that Coquerel’s Sifaka was inserted as a correction. The nearest bird of paradise is on an entirely different island – New Guinea, but considerable licence has to be allowed when dealing with common names. But what to make of the Cuvier Oplure? A google search turned up 358 results most of which bore a striking similarity to each other, this creature has an entirely new mode of reproduction, not sexual, not parthenogenesis but by an asexual means known as cut and paste.

In Madagascar Wildlife a Visitors Guide from Bradt Guides we find that “The presence of iguanids (family Iguanidae) is unexpected as the stronghold of the group is Central and South America“. There are no iguanas in Africa, nor have any fossils turned up there. The Madagascan representatives, seven species in two genera, were included in the Iguanidae on morphological grounds. DNA sequencing has opened up a whole new approach to working out patterns of descent and relationship and, as a result, taxonomy is undergoing considerable revision. The Madagascans now get a family of their own, the Opluridae. The genetic distance between them and the Iguanidae indicates that they shared a common ancestor well before the break up of Gondwana. It is likely that they rafted to their present position on Madagascar the Ark rather than by swimming.

Georges Cuvier (1769-1832) was to all intents and purposes the founder of modern vertebrate paleontology, the guy who demonstrated the reality of extinction by the careful comparison of fossil forms with modern animals and was the first to describe a number of Iguanid taxa. He thoroughly deserves to be remembered in the name of a reptile and so I present to you Cuvier’s Oplure, Oplurus cuvieri …

Or in English English (and as we have seen, not quite accurately) the Black-collared Iguana. It may be found on the ground or climbing trees and is common around Anjajavy.

May thirty-first …

Even more scary than carbon dioxide …

“This is a really big asteroid, similar in size to the one that killed off the dinosaurs, and it’s getting very close to us,” she said. “Fortunately we’ve been tracking its orbit very carefully so we know with great certainty it won’t hit us.

“We don’t need to panic, but we do need to pay attention,” she said.

Is that like, 97% of space scientists agree?

It’s 1.7 miles long. Its surface is covered in a sticky black substance similar to the gunk at the bottom of a barbecue. If it impacted Earth it would probably result in global extinction. Good thing it is just making a flyby.

Asteroid 1998 QE2 will make its closest pass to Earth on May 31 at 1:59 p.m. PDT.

Maybe it is, the trajectory of objects is space is about observations and calculations, not computer modelling. Still asteroids pose a far greater risk to life on earth than does CO2.

Full article <HERE>.

Stop extinction …

There are occasions, if I am confident that the company I will be keeping will be sufficiently mature, when I wear my Stop Extinction t-shirt. It’s not a bad looking t-shirt, nice picture and motto on the front and the Birdlife International logo on the shoulder. It was a freebie …

Interesting sentiment but somewhat impractical, extinction is the fate of every species, most of the species that ever existed on earth have already done it.

Some, I hope, will do it soon. The malaria parasites would fall in that group. Another little beauty is the Guinea Worm, Dracunculus medinensis, that causes Dracunculiasis. An ancient and once widespread disease, it is now confined to four African countries. You catch it by drinking water containing copepods (water fleas) contaminated with Guinea Worm larvae. The copepods are digested leaving the larvae free to pass through the gut wall into the abdominal cavity. After a while the boy and girl worms mate, the boy worms then die.

The female heads for the surface, sometimes in the lower abdomen, more often in the legs. A slow journey, painful to the host. By the time she is a year old she’s 60 to 90 centimetres long and ready to shed larvae herself. The tip of the worm perforates the skin causing intense burning pain. For relief the host dips the affected part in water, the worm sheds larvae, copepods eat the larvae, someone drinks the water and the wheel of life turns again. Exquisite.

Once the worm has shown itself, the time-honoured treatment is to slowly and painfully extract it by winding it around a stick, a process that takes hours to months. It may be the origin of the medical symbol of serpent and staff – the rod of Asclepius.

If on the other hand you think that every worm is sacred then you should visit The Save the Guinea Worm Foundation. You might like to volunteer to host one …

But if extinction really turns you on what about joining The Voluntary Human Extinction Movement.