Evolution, a Definition

That is all.

(Thanks to the I fucking love science group on Facebook for this one)

Demystifying the Coelacanth

A coelacanth (image: National Geographic)

A few days ago, Robin Stobbs (a frequent commenter on this blog) sent me an email in which he addresses some common misconceptions about the coelacanth. The coelacanth has been nicknamed the “living fossil” because until the discovery of live specimens it was only known through fossils.

I was always fascinated by this fish (although not nearly as fascinated as Robin who has spent more than 30 years of his career studying the coelacanth) but was not aware that it was the topic of more than a few bewildering myths and misconceptions. I found this extremely interesting, both because these fish are cool, and because I wasn’t aware of the pseudoscience and woo associated with them.

Robin was commenting on a coelacanth blog (extracts of which are in quotation blocks here):

In 1938 Majorie Courtenay-Latimer the first curator of the Natural History Museum in East London, South Africa, found amongst a ton and a half of a trawler catch a breathtaking blue coelacanth (pronounced “SEAL-a-canth).

Archival records in the library of SAIAB (ex JLB Smith Institute of Ichthyology in Grahamstown, South Africa) show quite clearly that the captain (Hendrik Goosen) and crew of the trawler ‘Nerine’ went to great lengths to preserve and set aside that coelacanth for Marjorie. The fact is the fish was not under a pile of trash fish. Nor was it blue when first seen by Marjorie C-L since like most blue-coloured fishes the colour fades very rapidly after death and that fish had been stone dead for many hours before it was brought into East London harbour.

Professor Smith waited until 1952, some 14 years after the first discovery before the next coelacanth was caught off the Comoro Islands, a remote volcanic archipelago at the head of the Mozambique Channel, halfway between Mozambique and Madagascar.

JLB (as he was known to family, friends and colleagues) was forced to wait out the war years following which he went to great lengths to distribute reward pamphlets along the East African coast. Meanwhile Comoran fishermen had been occasionally catching coelacanths unaware of their scientific value. So it was only the next known to science that was caught off Domoni in 1952!

Coelacanths are able to swim forward, backward, upside down and on their heads.

Like any other fish – especially those that propel themselves by using their paired fins rather than their tail and caudal fin!

Coelacanths live 400 meters beneath the surface. During the day they are inactive seeking protection in volcanic caves. At night these nocturnal predators are on the hunt. Their luminescent alien-green eyes have adapted to extremely low light levels – so much so that they do not hunt during a full moon.

An analysis of catch records from the Comoros (and recently updated by Rik Nulens[1]) show that coelacanths have been caught or observed from as shallow as 50 metres with unconfirmed sightings and a catch from less than 30 metres. Coelacanths living off Madagascar and the East African mainland coast do not have volcanic caves for refuge. Instead they seek shelter in overhands or shallow ledges.

Nobody has tested the low-light vision of Lartimeria and it is only presumed they have low light vision from the eye anatomy and eyeball size! My analysis of recorded catch dates compared to moon phase show that there is no correlation between the two – as many coelacanths have been caught off the Comoros during periods of full moon as there have during the new moon! There is, however a skewed idea resulting from the fact that the target species of Comoran fishermen is the oilfish, Ruvettus pretiosus, and this is primarily caught on nights when ambient light is of a low order.

The hollow spine of the coelacanth is composed mainly of a flexible cartilage – similar to a shark. Its spinal fluid is viscous golden and rumoured to act as an elixir. Coelacanths are thought to live for at least 40 years.

 

The coelacanth’s swim bladder is a slender oil-filled tube embedded in fat below the spine – it serves to increase its buoyancy.

The fluid contained within the ‘spinal cord’ is a low viscosity lipid, under slight pressure, and is similar to the lipids that fill every sinus and organ of the entire body. The swim bladder is fat-filled. Buoyancy is maintained by the entire lipid-filled body of the fish and so, like many sharks, the fish is capable of considerable vertical movement in the water column – there are no gas-filled sinuses that undergo compression or decompression!

The superstition about this fluid being sought after by Orientals because of some supposed elixir was started by some irresponsible reporting and an article in the Tropical Fish Hobbyist in the 1980s!

In 1987 a submersible located and filmed wild coelacanths off the Comoro Islands.

And since then coelacanths have been flmed or photographed in their habitat by divers and ROVs in Indonesia, Madagascar, South Africa and along the Tanzanian coast.

In 1998, Professor Mark Erdman, University of California Berkeley, discovered a new golden brown Indonesian coelacanth Latimeria menadoensis some 10,000 kilometers from the Comoro Islands in the Indian Ocean.

Actually the Indonesian coelacanth has the same colouration of the Indian Ocean ones – a clock spring steely blue with white to off white or pink blotches the pattern of which is characteristic of the individual (rather like a fingerprint).

Three hundred years before Agassiz found the first fossilized coelacanth, Mayan metallurgists were making exquisite miniature silver coelacanth jewelry [sic].

This has been shown to be false. The silver coelacanth votives were made by modern silversmiths – I don’t have the reference at hand but it was reported b Hans Fricke et al among others. There is nothing coelacanth-like in the little silver ornaments supposedly made by Mayans!

***

Thank you very much for taking the time to share your knowledge Robin.

***

[1] “An updated Inventory of all known specimens of the coelacanth, Latimeria spp.” Rik Nulens, Lucy Scott and Marc Herbin. Published as a Smithiana Special Publication by the South African Institute of Aquatic Biodiversity (SAIAB), 22nd September 2011

Image from National Geographic.

 

News24 midget advert not science

Anyone who knows me will be aware of my long-standing gripe with the Science & Technology department at News24. They seem to have low editorial standards to start with, but today I have officially lost my cool. Today they decided to publish another Piece by Duncan Alfreds entitled SA Man Seeks Midget to Kick Ex, and here it is in it’s entirety:

Cape Town – A Randburg man has posted an advert in which he would like a midget to kick his ex-girlfriend on the shins on the Gumtree classifieds website.

“I was recently dumped and require the services of a midget to go and kick my exgirlfriend in the shins whilst she is at work,” he writes.

The man, known only as Brett, works for a marketing company, told the Star that his advert was not a joke.

“I clearly took it out because I want my ex-girlfriend to be kicked in the shins. Midget revenge is the only form of revenge that works these days,” he said.

He added that his ex had dumped him after dating for two months.

The advert had been viewed over 2 600 times by Friday and Brett rejected suggestions that his ad was discriminatory toward people with dwarfism.

“Fuck if I care. They know they are midgets. I’m not being politically correct about this.”

Brett also rejected accusations that he was promoting violence against women because the advertposted on February 27 says that his ex should be kicked “once (not too hard) in the shin, and leave”.

It is unclear how much Brett is willing to pay for the service.

- Follow Duncan on Twitter

Sure, this is funny, but it is gutter journalism and has NOTHING to do with science. Please follow Duncan on Twitter and tell him how ridiculous this article is, and then demand that he writes something of substance.

I am going to do that right now. Then I’m going to write a letter to the editorial department of News24 and express my deep disappointment at their decision to hire a pseudo-journalist like Duncan, to put him in their science portfolio, and to publish crap like this.

Disgusting!

EDIT:

Since I wrote this post, News24 deleted my comment on the article in which I criticised this infantile rubbish. I’ve posted another comment calling them out on it, let’s see how long it takes for this one to be deleted:

Wow, News 24 has deleted my original comment where I criticised them for publishing this gutter journalism as Science.
Looks like censorship is alive and well at News24. Well done guys, can’t take the heat, press delete.
It doesn’t change the fact that Duncan Alfreds submits poor-quality science journalism at every turn. In fact, I am yet to read a single decent piece by him. You would do your reputation a bigger favour if you deleted his name from your payroll instead of deleting my criticism from your website.

Edit #2:

News24 has now deleted the above comment from the article as well. They really do like to silence criticism.

GPS error might scupper FTL neutrinos

Is this thing on?

An announcement late last night (South African time) stated that a fault in one of the GPSs used in the OPERA experiment, that measured bursts of neutrinos travelling slightly faster than the speed of light, might be the mundane explanation behind this extraordinary finding.

Sciencemag reports that a source says that a bad fibre optic connection between the GPS receiver used to correct the timing of the neutrinos’ flight and an electronic card in a computer might be the source of the FTL neutrino results reported in September last year.

Of course, the experiment will have to be repeated once the faulty connection has been rectified, just to make sure that this actually accounts for the difference. This is how science works.

But I still haz a sad

Evolution is not an insult against humanity

Of all the great battlefields of science, the debate between creationists and people who accept the theory of evolution is the most fraught with emotional obstacles. And how could it be otherwise? These are two diametrically opposed ideas about the origin of life on Earth. (*Evolution does not deal with the first appearance of life, that is a separate concept called abiogenesis – the formation of life from non-life.)

On the one side we have the scientific community (and those who support the scientific community) who accept the evidence of fossil and genetic data and do not add any supernatural explanation to the origin of life (*or the descent of all species from that point).

On the other side we have the proponents of a faith-based idea of how man arose to walk the planet. This is a religious standpoint based on the writings of a holy book of some denomination it is not revised or based on evidence.

I’m not going to get into much more of the rigorous debate than that (unless you really want me to!). What I want to do is look at some of the uncommon claims, made by proponents of either camp, to see whether or not these ideas hold water.

I’m going to cull these nuggets from discussion boards and comment threads whenever I find them, and then take them apart carefully here.

The first lady for a shave is August, who posted the following gem on Athiest, Agnostic and Non-religious, a facebook group I participate in. August says:

I really didn’t understand that either. And I had a suspicion that August was just trolling, so I went rolling on over to his/her profile and found a note with a slightly more… “thought out” version:

August’s comment displays one of the most staggering misunderstandings of the theory of evolution that I have ever come across (which is why it inspired this post). August believes that when we die our bodies will return to the form from which they were created. This is really quite a bizarre idea. But cremation is not a natural process, and can’t possibly be a useful way of determining anything to do with the origin of our species.

When we die, our bodies decay into their constituent elements, assisted by time and the digestive tracts of numerous scavengers. By August’s tortured reasoning, when we are buried we would turn to dust as well. But what we do is more akin to turning into plants and worms and other things that harvest the nutrients we have been hogging for so long.

What happens to our bodies after death has less than nothing to do with the theory of evolution. It would be like claiming that gravity doesn’t exist because the sky is blue. The two concepts are completely unrelated. This is a beautiful example of a non sequiteur, a conclusion that does not follow from the premises.

The theory of evolution states that all the life forms that are alive on the planet today, and all those species that have gone extinct after a brief flurry of activity, are descended from many generations of species that came before them. That’s the abridged version.

August is so wrong that he/she isn’t even wrong.

August’s comment on the AANR group states that evolution is insulting to humans because it suggests that we are descended from apes. This is also wrong. The theory of evolution states that humans and apes have a common ancestor. About 6 million years ago, the ancestors of humans, chimpanzees and bonobos were the same grassland dwelling creatures. Neither human, nor chimpanzee but some magnificent forbearer who gave rise to all the species of humans and chimpanzees that have existed since that time. (Owen has pointed out an omission, humans are apes.)

Knowing this is not an insult, it is a glorious moment when you realise that you are not separate from your fellow creatures. You are not better, somehow remote and above them. You are, in a sense, connected to every ape, monkey, mouse, frog, tree, mushroom… everything. And that connection is in every cell that makes up every part of your body.

This is the deepest kind of connection possible, and we all share it. Without the theory of evolution, and the hard work of geneticists, we would never know this.