Tasmanian Devils And The Evolution Of a New Species Of Parasitic Tumour

Creationists love to misrepresent evolution and have an inordinate fondness for strawmen. These include:

1. Evolutionary change requires in increase in “genomic information”
2. Evolution only occurs within “kinds”
3. Speciation does not occur (incompatible with 2).

Number 1 would imply that genome size correlates with complexity. It does not. The largest known genome belongs to the single celled Amoeba dubia at about 600 billion base pairs. This is 200 times larger than our own genome. Even the lungfish Protopterus aethiopicus has a genome 50 times larger than ours. See here for phyletic comparisons .

This strawman also ignores the reality that some genes such as Abd-a can inhibit the development of complex structures such as abdominal appendages in invertebrates. Furthermore, subtle changes in regulatory sequences can affect morphological development that is controlled by genes already present. An example would be the expression of Bmp2 in the developing forelimb of bats .

One final problem for creationists is that natural or experimental deletions of parts (or the whole) of Alx-4 (loss of “information”) increases digit number in mammalian limbs – ie, less “information”, greater “complexity”.

Number 2 is just absurd as the spatio-temporal distribution of any number of transitional fossils shows. The creationist concept of “kind” is also confused.

Number 3. It happens! Deal with it creationists!

Now to the point, Jerry Coyne has posted this fascinating summary of work on tumours of Tasmanian Devils. It is significant because the tumours seem to have originated in an individual Tasmanian Devil and are now transferred from individual to individual by bite. Thus, making it a new species of parasite that is derived from the host species. It has obvious implications for all three points above. It is well worth a read.

Young Earth Creationism Is a Pain

I'm suffering from the cold just now and a simple refutation of the YEC position popped into my mind. If the Christian god supposedly created us in a perfect world with no pain or suffering, where Dinosaurs supposedly ate tofu , then why do we experience pain? Without going into the details, our bodies have complex pathways to perceive pain and produce painkillers (like endorphins). So, why can we feel pain and possess mechanisms to modulate it?

Closely associated with this is tissue damage. Why do we have complex repair mechanisms and the blood clotting cascade? Interestingly, Michael Behe claims that the blood clotting cascade is irreducibly complex and could not have evolved. Creationists want it both ways it seems. This idea is of course nonsense and is refuted here.

Here's an amusing if not painful song.

Bloodless Icefish Makes Creationism Look (Even More) Anaemic

Time for some more creationist bashing. I am preparing a post on the evolution of antifreeze proteins in Notothenoid fish. However, there is also something else interesting about this group.

Let’s see people draw their own conclusions.

Fact 1: All vertebrates have genes for haemoglobin (see fact 3).

Fact 2: 16 species of Notothenoids do not express haemoglobin. (the only known vertebrates without haemoglobin)

Fact 3: 16 species of Notothenoids do not have any functional haemoglobin genes.

Fact 4: 15 of these species have no beta haemoglobin gene and retain a shortened form of the alpha gene.

Fact 5: The remaining species (Neopagetops isionah) has two non functional pseudogenes for beta haemoglobin. One contains only part of the 3rd exon and is very similar to the same fragment of the closely related and haemoglobin bearing Dragonfish. The other pseudogene is closely related to that of other Notothenoids.

Your conclusion ladies and gentlemen: Evolution or creation?

A more technical account can be found here.


Fundies, it may be worth bearing this in mind:

Hebrews 6:18 “God did this so that, by two unchangeable things in which it is impossible for God to lie, we who have fled to take hold of the hope offered to us may be greatly encouraged."

But, then again, maybe not….

2 Thessalonians 2:9-12 “The coming of the lawless one will be in accordance with the work of Satan displayed in all kinds of counterfeit miracles, signs and wonders, and in every sort of evil that deceives those who are perishing. They perish because they refused to love the truth and so be saved. For this reason God sends them a powerful delusion so that they will believe the lie and so that all will be condemned who have not believed the truth but have delighted in wickedness.”
Ooops!

Maybe that means that you can’t trust any of the bible. The evidence above exists despite what your book says about it.

Wasp Stings Young Earth Creationism In The Bum

Over at the Mac Gafraidh blog, I questioned Chelsea on whether she took the following verses literally:

“And God said, Behold, I have given you every herb bearing seed, which [is] upon the face of all the earth, and every tree, in the which [is] the fruit of a tree yielding seed; to you it shall be for meat. And to every beast of the earth, and to every fowl of the air, and to every thing that creepeth upon the earth, wherein [there is] life, [I have given] every green herb for meat: and it was so.” (Genesis 1:29-30).

Like all biblical literalists, she said that she does believe this. These verses basically says that all animals were created to be vegetarian - an absurd position to hold. We need only think about carnivores and their killing adaptations like the canines of big cats that that are so good a piercing flesh – and just happen to be at the right spacing to dislocate the cervical (neck) vertebrae of their main prey species. Then there are species of fish specifically adapted to eat scales and fins (eg Perissodus sp and Exodon paradoxus). One species, the Sabre tooth blenny (Aspidontus taeniatus) even mimics that Cleaner wrasse (Labroides dimidiatus). Cleaner wrasse pick parasites, which are themselves highly specialised non vegetarians (see my article on Trypanosomes for an complex example of adaptation to living inside and off of another species). Fish approach cleaner wrasse to be serviced and the wrasse signals back. This signifies the intentions of both parties and wrasse are even allowed into the mouths of large predators, where they are unharmed. Sabre tooth blennies on the other hand do a similar display but instead of cleaning the other fish, they take a chunk out of it. This is a problem for YECs.

However, I want to use an example that Darwin used (more against the idea that god was a loving creator). He cites the Ichneumonoidea – a group of parasitoid wasps that lay their eggs in the living bodies of their insect hosts (usually caterpillars).

Darwin writes:

“I own that I cannot see as plainly as others do, and as I should wish to do, evidence of design and beneficence on all sides of us. There seems to me too much misery in the world. I cannot persuade myself that a beneficent and omnipotent God would have designedly created the Ichneumonidae with the express intention of their feeding within the living bodies of Caterpillars, or that a cat should play with mice.”


There are several special adaptations that are needed:

A suitable host must be located.

The host must become infected – hence the long ovipositor. Some species (eg Ephialtes manifestator) can locate their host through wood and drill to them . Other species also paralyse their hosts, so the toxin is yet another adaptation. Many species also parasitize dangerous spiders so avoiding becoming dinner is another adaptation.

The larvae must evade the hosts’ immune system.

The larvae must keep the host alive and fresh for as long as possible to ensure fresh meat.

In the example below, involving the Blue butterfly as a host, we see several adaptations. These include locating the host and distinguishing it from ant larvae (bear in mind that the ants can’t even do that) and avoiding being attacked by the ants. This latter applies to both infected pupae and adult wasps.

So, the fundamentalist is left with a problem. How did these specific adaptations arise if animals were intended to be vegetarian? They either have to claim god made them that way (lacking any evidence) or claim that some evolution occurred – although that would have to be incredibly fast for a vegetarian wasp to become a wood drilling, ant avoiding spider paralysing, immune system evading parasite.

Of course, the problems for YECs don’t stop there. They believe in the flood. There were only of two of every non clean kind on the ark. That means no ant colony to feed the blue butterfly larvae for the Ichneumon to eradicate. Mind you, the ants would have been killed by lancet flukes (Dicrocoelium lanceolatum). That’s if Anty the ant eater didn’t get them first.

The Platypus: Piss Poor Creationist Scholarship Or Wilfull Mendacity?

Platypuses (Ornithorhynchus anatinus) are excellent examples of primitive mammals that retain some reptilian features – such as egg laying. But, for some reason creationists seem to claim the platypus is a problem foe evolution. I often get this link thrown at me as if it proves that platypuses are a mosaic that contain parts from reptiles, mammals and birds, and therefore could not have evolved.

Let’s look at some of the creationist claims and expose more lies and misrepresentation.

1. It has a bird’s bill.

No it doesn’t! A bird’s bill is mainly made of the protein keratin. A platypus’s is leathery, flexible and contains numerous sensory pits

2. It lays eggs like a bird.

It may lay eggs, but they have leathery shells like reptile eggs. They are not surrounded by a shell like those of birds. This is what you would expect with the evolution of mammals: egg laying “reptiles” becoming egg laying mammals, which become live birth giving mammals. So, where is the problem?

3. It has a spur on its hind limb that produces a toxin similar to that found in reptiles.

Again, so what? That is what you would expect if they evolved from reptiles. In the link above, the author is also misleading. The platypus toxin actually evolved independently of the reptile venom. Both evolved from beta-defensin genes, but different classes of them , so although they are similar, there is no claim that one is descended from the other – that is creationists being naughty trying to play up the mosaic idea. The plan is to say Ha! Look they are almost identical to reptiles, but wait, they have genes found in birds too. Therefore evolution is wrong.

4. They contain genes for the egg protein vitellogenin. As the article claims, these genes are also found in fish and birds.

Again, we have some more naughtiness by omission. As the article is read, there is no mention of amphibians and reptiles. So, if it is not present in these groups, that would be a problem. Being a scientist, I’m not scared to make a testable prediction. I predict these groups contain vitellogenin genes (why don’t creationists make testable predictions? Answers on a post card). So, lets search the best database for finding peer reviewed scientific research publications (try it yourself). Let’s search for vitellogenin and amphibians. Well, no surprise there, 398 articles containing those key words, and plenty of papers on African clawed frogs (Xenopus laevis). What about searching for vitellogenin and reptile? This time, we get 62 publications describing its occurrence in snakes, crocodilians, iguanas and turtles. So, the evolutionary scenario of fish to amphibians to reptiles; which split into birds and mammals (via egg laying mammals) stays intact.

5. They contain ZPAX genes that are found in birds, amphibians and fish.

Note, there is no mention of reptiles here. That’s because they have not been looked for in reptiles – you won’t find it in pubmed. Here is another prediction for creationists, reptiles possess these genes – wait and see. The organisms that it has been studied in show a definite evolutionary relationship between groups, based on gene similarity see here.

6. Some of the sex chromosomes are like those of birds.

Platypuses have an unusual arrangement of sex chromosomes - there are 10 of them. They do follow the basic mammalian X Y sex determination pattern, with all X causing females and Xs and Ys together causing males. If they have evolved from reptiles, we would expect some similarities to reptilian sex chromosomes. Reptiles form 2 main groups when it comes to sex determination. Those were environmental factors determine sex and those where sex is determined by sex chromosomes (Z and W for female and two Zs for male). This is the system that birds have inherited. In the platypus, the Y chromosome seems to have evolved independently, with the X chromosome alone showing some similarity to both the reptilian and avian Z chromosome – from which it evolved.

7. They contain some avian like micro RNAs.

Guess what; at least one of the X chromosomes encodes some micro RNAs (see above).

Creationism has no evidence of its own and relies on dishonest misrepresentations and straw men concerning evolution.

I’m off to put some brights cards under the wipers of cars that have “you make Jesus cry” (puke-arama) stickers on them – again!

A Very Bad Case For Design

Creationists have a lovely way of shooting themselves in the foot by taking the worst possible example to try and justify their case. This recent comment (found here) exemplifies this beautifully

“To know something and to assume to know something is different. Example, one lives alone and he/she goes home and just saw that dinner table is served with all kinds of fruits and food. Now I am thinking and conclude that somebody prepared all the food and served it. But Steve and Dawkins ASSUME that all the food came up there by chance and Luck. This world with their related seasons which act like a servant is a very big food stale where we eat all the food according to the our body needs. Vitamin C or D etc. Who created human beings created the soil where all food fruits and veggies can grow and who created the soil, created the sunlight and rain that all cooperate with each other to serve us.”


Here is the real problem (other than the obvious misunderstanding of evolution and the absurd analogy): Our ancestors once made vitamin C for themselves. They did not need to ingest it. We lack a functional gene for an enzyme called L-gulonolactone oxidase. This forms the last step in the production of ascorbate (vitamin C) from glucose. We do however contain a pseudogene for this enzyme, which does not function because of acquired mutations. This presents a problem for the creationist.

The problem is that design requires being made to fulfil a purpose. Creationism boils down to an organism must be designed because it fulfils a purpose and all its parts are created to fit together to perform that purpose (that and a lack of imagination). So, here we have something that has no purpose and its only reasonable explanation is that it was present in a functional form in our ancestors (it probably became inactive about 40 million years ago).

Reductionism is a common theme in biology. If we don’t need a gene, there is no selective advantage in keeping it. There may even be a slight energetic advantage in losing it. Genes are lost through random mutations, and there are many examples of this occurring. It is not just the L-gulonolactone oxidase gene that we have lost; mice and humans have about 200 “genes” for a family of olfactory (scent) genes called the V1r family. Mice have about 160 functional ones. Humans have only 5! Whales and dolphins have no functional members. The non functional ones have become fossilised in our genome; they are slowly decaying. Gene loss is seen at an extreme level in parasites, as their hosts provide much of what they need for them. The record holder is Mycobacterium leprae; it has about 1600 functional genes and approximately 1100 decaying fossil genes.

It is not just genes that are lost, but structural features too. Examples include the toes of horses that can be seen gradually disappearing in successive rock layers, our appendix and the limbs of proto-snakes (Figure 1).

An interesting recently described example of this is the eyes of blind cave fish. It was found that functional eyes could be restored by interbreeding populations isolated in different caves. This is important. The fact that they have been isolated from each other means that the blindness evolved independently in the different populations. The fact that cross breeding some populations restored sight in the offspring means that different genes are responsible for the blindness in different populations of the same species – surely design would mean this should not be possible – as the perfect designer would chose the one way to make these fish blind – unless of course he wanted to make it look like evolution – just like chromosome 2.

One final point on vitamin C: inerrant biblical literalists believe that all animals were intended to eat plants and fruit (genesis 1:29-30). However, these foods contain vitamin C, so our ancestors would not need genes to synthesise it.

As one can see below, the teeth of Carcharocles megalodon are beautifully designed to peel grapes (sarcasm in case creationists are reading).