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Tommy Leung
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Of Pigs, Chimps, And Dinosaurs
[Brace yourself, this is a long read]
It seems like ever since mid-2013, not a month goes by without hearing about what I would call "PigChimpMan theory" of human evolution. This "theory" has been lurking around for a while in its own obscure corner of the internet, but it initially came to the attention of a wider online audience via PhysOrg back in July 2013. However, the idea was well and truly launched like a dysfunctional bottle rocket in November 2013 into the mainstream when it was publicised by that bastion of rigorous science journalism, the Daily Mail. Subsequently, it had spread like a pandemic swine flu across other media outlets.

(BTW, I'm not going to link to those pages directly and give them the hits, but if you wish to see them, they can easily be found via a quick Google search)

But we're not here to talk about that, as the ridiculousness of that theory has been thoroughly addressed by +PZ Myers 
http://freethoughtblogs.com/pharyngula/2013/07/02/the-mfap-hypothesis-for-the-origins-of-homo-sapiens/
And it was also addressed on episode 420 of Skeptic's Guide to the Universe (http://www.theskepticsguide.org/podcast/sgu/420).

To say that the originator of the "PigChimpMan theory" has some odd and misguided notions about evolution would be an understatement and it is not on the basis of the "PigChimpMan theory" alone. No, lest you think we are talking about a one-trick wonder, fear not - he also has a website call Macroevolution Dot Net (once again, I'm not linking directly for reasons stated above). This is where he has published many other "theories", though admittedly most of them appear to simply be a variation on a very simple theme, namely "X did the nasty with Y and ended up with Z"

Okay, some #realtalk  here - cross species hybridisation does happen - for example, a mule is a hybrid between a donkey and a horse, and there are also hybrids between domestic cattle and American bisons, and even hybrids between false killer whales and dolphins.

He claims that such hybrids lend support for his "PigChimpMan (and other similar) theory". However such hybrids are often sterile and only occur between species which are closely related - often from the same genus. The "PigChimpMan theory of human origin" is based on a faulty, slippery slope assumption that since hybridisation between closely related species is possible, then species across entirely different orders can readily hybridise. Just because two closely related species can form hybrids does not mean animals from entirely different orders (or entirely different classes as you'll see below) can produce reproductively viable hybrids. Basically, just because there are mules running about doesn't mean that Manx cats came from a rabbit humping a cat.

Oh, I forgot to mention that didn't I? That the creator of Macroevolution Dot Net thinks that Manx cats http://en.wikipedia.org/wiki/Manx_(cat) are actually cat-rabbit hybrids? Just FYI. But cross-order hybridisation is nothing comparing with his proposed origin of the monotremes (platypus and echidnas) which involve birds hybridising with mammals. Yes. Your read that right. He thinks that the echidna exists because a hedgehog got it on with a kiwi. Don't take my word for it - go to his website and check it out for yourself.

But it doesn't end there (it never does), let me present his "They look kinda alike to me" theory of evolution. He has some very strange ideas about dinosaur evolution which I am sure scientists like +Michael Habib or +John Hutchinson or +Darren Naish or just about anyone else who have at least some interest in and background knowledge about dinosaurs would find, well, questionable to say the least. For example, did you know that according to Macroevolution Dot Net, pangolins evolved from stegosaurs?

His "theory" pretty much amount to "Pangolin looks kinda like a Stegosaurus. An anatomically inaccurate Stegosaurus from an old kids book about dinosaurs I came across. And if I ignore just about everything about both animals. Therefore, I think pangolins are actually descended from dinosaurs and Stegosaurus is a mammal" Go check it out for yourself - I seriously, seriously cannot make this stuff up even if I tried. He thinks that pangolin plates are homologous* with the plates of Stegosaurus and that the tail spikes on the thagomizer of the stegosaur tail actually belong on the feet and were homologous to the pangolin's claws.
*A homologous structure is a one which is found in different species that share a common ancestry; for example, our arms are different from the wings of a bat - both have been modification for different purposes in our respective lineages - but they share a common basic architecture from a common ancestor.

He also claims that:

"The modern giant armadillo is so similar to the ancient ankylosaurs that it is only reasonable to suppose it is descended from them."

According to his theory, thyreophoran dinosaurs are in fact mammals. Well, I guess by that logic, one can claim that it is only "reasonable" that dolphins are descendants of ichthyosaurs, right? Right? Well...when he is not busy trying to claim one group of reptiles are mammals, he is also trying to claim that one group of mammals are in fact reptiles. The mammals in question are the cetaceans - whales.
 
While he is not exactly claiming that dolphins are evolved, modern ichthyosaurs, he does think that whales had evolved from mosasaurs. The mosasaur were a group of extinct marine reptiles which are related to modern monitor lizards and snakes that lived during the late Cretaceous period (http://www.oceansofkansas.com/about-mo.html) and they are essentially a lineage of lizard-type reptiles that had adapted to the aquatic environment.

Despite extensive fossil AND molecular evidence for the actual evolutionary origin of whales, he still cite his "They look kinda alike to me" theory of whale evolution, while being unfamiliar with something call convergent evolution (http://en.wikipedia.org/wiki/Convergent_evolution) whereby divergent groups of organisms have independently evolve very similar forms as they lived in similar ecosystems/environment and were subjected to similar evolutionary selection pressures.

If you want to read up on the non-unhinged theory about evolution of whales, this Wikipedia article has a good collection of links and references you can look up and read at your leisure: http://en.wikipedia.org/wiki/Whale_evolution

Oh, one more little thing - he also has this annoying habit of repeatedly following and unfollowing people on Twitter to try and get them to follow him back. +Steven Hamblin called him out on this, to which he claims that it was "an accident" (he has also deleted all his tweet correspondence with Steven), but others have mentioned that they have been subjected to the same "follow-unfollow" cycle from him.
https://twitter.com/BehavEcology/status/402239297069129728
https://twitter.com/BehavEcology/status/402246415226658816
https://twitter.com/BehavEcology/status/402253272641064960
https://twitter.com/BehavEcology/status/402255907670609920
I think I'm currently in the third or fourth "follow" cycle from him, though I suspect this post might terminate that altogether.

To lighten the mood a bit after this very long post/rant, I would like to propose a new genre of internet literature call "Macroevolution Dot Net Fan fiction" (I think I have just invented the worst kind of fan fiction). Here are some potential title to start off with, but feel free to make your own.

Loris = Monkey + Owl hybird
Ambulocetus = Otter + Crocodile hybrid
Sea cows = descendants of placodonts (http://en.wikipedia.org/wiki/Placodont)

Then again, he is probably working on those very ideas right now...
Sharing for +ScienceSunday 
#sciencesunday   #pseudoscience   #evolution   #evolutionarybiology   #scienceeveryday   

Accompanying photo is "The Listener" (2013) by Patricia Piccinini. You can see the rest of her artwork here: http://www.patriciapiccinini.net/
Photo was taken by Ars Electronica and used here under Creative Commons license (CC BY-NC-ND 2.0). Original here: http://www.flickr.com/photos/arselectronica/9415769898/
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Worth noting that the Skeptics Guide to the Universe chose the "man-chimp-pig" story as one of the worst science failures of 2013, alongside such luminaries as "vaccines make you gay" and "bigfoot DNA". Lots of angels singing in this choir: http://www.theskepticsguide.org/podcast/sgu/441

Tommy Leung

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The Lost Snail
I talked about Leucohcloridium, a mind-controlling snail parasite on a radio segment here: https://soundcloud.com/abcnsw/creepy-but-curious-tommy-leung-the-lost-snail
 
Tale Of The Lost Snail
Accompanying audio here: https://soundcloud.com/abcnsw/creepy-but-curious-tommy-leung-the-lost-snail
The radio show I was doing last year - Creepy but Curious - is back for 2016! I kick things off this year by telling the story of the Lost Snail - a parasite call Leucochloridium which not only takes over the body of the amber snail, but also tampers with its little snail mind. So if you like hearing story about body-snatching, mind-bending parasites, follow the link here: https://soundcloud.com/abcnsw/creepy-but-curious-tommy-leung-the-lost-snail

#scienceeveryday  
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Of Chimps, Leopards, And Toxoplasma
Some of you may be familiar with the story about a little cat parasite call Toxoplasma gondii. It seems to be able to alter rodent behaviour so that they are more likely to be eaten by a cat, but it can also infect humans (and any warm-blooded vertebrate animal) and supposedly mess with human behaviour as well. Spoooooky. At least that's how the story goes. Like any other story, there is some grain of truth to it, but it is buried within a whole mass of (more sensationalised) dross. Any studies into Toxoplasma and host behaviour manipulation has the potential to go viral as it includes all the elements that makes a good headline - it contains cats, brain parasites, and zombies (in the form of host behaviour manipulation).

The literature on Toxoplasma and host behaviour is MASSIVE - some of it is good science, others are more like tabbies dressed as tigers. But for this post, I'm going to focusing on one story within a larger narrative, I want to talk about a paper recently published in Current Biology which had whipped the media into a frenzy (again) about how human behaviour is affected by Toxoplasma. http://www.cell.com/current-biology/abstract/S0960-9822%2815%2901517-1

Here's a tl;dr version of the study. The study found that compared with uninfected chimps, chimpanzees infected by Toxoplasma are not as averse to the odour of leopard (their natural predator) urine. The researchers concluded that this is because Toxoplasma is manipulating the chimps' behaviour so that they will be more likely to be eaten by a leopard (the final host for Toxoplasma are felines).

1) While the media coverage seems to be focused on how the parasite affects human behaviour, this experiment was done on chimps, and the media is extrapolating the conclusion of that study to humans. Humans and chimps may be genetically similar on some level, we have been separated by 5-7 million years of evolution, and our ancestors evolved in very different environments. There are some very key differences in the behaviour of chimps versus humans.
 
2) The study was not only correlative in nature, it was based on testing chimps for presence of Toxoplasma antibodies - not the parasites themselves, just a potential indicator of the parasites presence (having antibodies for something doesn't guarantee the presence of the said thing in the body). The researchers didn't confirm the presence of the parasites themselves. I understand they can't exactly do the latter for ethical reasons, in which case, maybe don't cannonball your way into such sensationalised conclusions?

3) The study tested how chimps response to the odour of urine and other big cats - the question is, just how much of a role does the sense of smell play in chimpanzees' predator avoidance repertoire? There is surprisingly little research on that. Is the sense of smell that important for predator avoidance compared with their other senses? Also, considering that chimpanzees are social animals, they would also rely upon other individuals in the group to warn of the presence of predators - you can't consider the vulnerability of a chimp to predation without the context of its social structure.

4) They mention potential behaviour variations between individuals (i.e. personalities) which may account for different level of aversion towards leopard urine odour which are pre-existing, regardless of the parasite. Good. But then, they just dismiss that possibility outright, by citing a single study that has found Toxoplasma is associated with disrupted fear response - in rat. Studies in other animals have shown that propensity for "recklessness" varies between individuals, even without the influence of parasites. So they're essentially saying Toxoplasma is the only possible explanation for why those chimps behaved slightly differently (in one aspects - response to leopard urine odour), even after bringing up the possibility that these behaviour variations exists regardless of parasitism, and discounting the dozens of other equally valid potential explanations. Not Wow.

5) Furthermore, when I dig into the methods, I found that the study was conducted on captive chimpanzees. Captive animals (especially behaviourally complex animals such as chimps) are known to exhibits behaviour which deviate significantly from their wild relatives. So we have no way of establishing whether such behaviour is representative of how they would behave in a natural setting (let alone extrapolating it to humans as the media has done). Once again, I understand that it would be extremely difficult to conduct such a study on wild chimps, in which case, the point I bring up in (2) still applies - don't jump to such sensationalised conclusions

6) Given the correlative nature of the study, we have no way of establishing how these chimps would have behaved before getting infected with Toxoplasma. So you can't rule out that maybe the chimps that behaved "oddly" are simply more likely to pick up Toxoplasma. They did mention this possibility, but they dismissed it just as quickly in the same manner as I described for (4).

7) The paper has 10 references in total (the supplementary material has 2 additional reference, but they were for methodological techniques), but did not cite a review recently published in 2014 in Advances in Parasitology which discussed at length the wide array of inconsistencies and seeming contradictory results from rodent-toxoplasmosis behavioural studies.
https://books.google.com.au/books?hl=en&lr=&id=ftnEAgAAQBAJ&oi=fnd&pg=PA109

And that's all I have to say about that. Peace out.
MFW I read another over-hyped "Toxoplasma gondii + host behaviour modification" paper pic.twitter.com/hOf8i62zWn · Tommy Leung – @The_Episiarch. I don't always subtweet, but when I do, it's about papers on Toxoplasma gondii and behavioural modification. Embedded image. 5:27 PM - 10 Feb 2016 ...
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This is interesting homies, for real!
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Ghili In The Belly
I have written a new Parasite of the Day blog post! This post is about Artystone trysibia - a parasitic isopod which is found in Amazonian fishes. While it is related to the infamous tongue-biter, the parasitic habit of this species makes its more famous cousin seems almost quaint. Follow the post below to find out more!

#scienceeveryday  
The tongue-biter Cymothoa exigua is arguable one of the most (in)famous fish parasite in the world. It was famous enough to get a mention on the Colbert Report, and while the world recoil in collective horror at the sight of ...
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Quelle horreur. ..Vu de près 
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The Worms of Beasts, Tragic Romances, and Body-Snatchers
I have written an end-of-2015 round-up post for the Parasite of the Day blog! A look back on 2015 and some of the fascinating parasite stories that were covered on the blog this year. From pea crabs to kangaroo leeches to hairworms and vampire snails, you'll find links to them all in the post below!

#scienceeveryday  
It has been yet another year of parasitology, and this year has been my fifth year writing on a regular basis for Parasite of the Day! So what had been on the parasite menu for 2015? First of all, some of the parasites that ...
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Not so much but thanks
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Zombie Ants And Monster Girls
"Hey Tommy, that 'Disney Princesses Reimagined As' trend got pretty popular, how about you do something like that?"
"How about...Parasites reimagined as MONSTER GIRLS?!"
"I…I don't think anyone wants that…"
"TOO LATE."
See also a related post here:
https://plus.google.com/+TommyLeung/posts/J2CiWHwHkvx

Alternative title: 
"I'm Not Popular, So I'll Draw Parasites As Monster Girls."
Apparently I wasn't quite done with Parasite Monster Girls. After I drew Luci the Zombie Snail Monster Girl my brain decided that drawing one monster girl featuring a mind-control parasit...
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Hot Single Eldritch Horrors In Your Dimension
So I finished working on this piece in time for Valentine's Day - basically, at some point, I decided that if I ever make a game (though realistically I lack the programming skills and time to do so), it'll be a dating sim visual novel-style game where you date monsters and abominations. So imagine Hatoful Boyfriend (https://en.wikipedia.org/wiki/Hatoful_Boyfriend), but with Eldritch Horrors instead of birds.
I wanted to revisit the Bestiary of the Eschaton, which I finished drawing for at the end of 2013 - it was fun and served as a great source for my creatively outlet for almost 7 years, but it didn'...
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Tale Of The Lost Snail
Accompanying audio here: https://soundcloud.com/abcnsw/creepy-but-curious-tommy-leung-the-lost-snail
The radio show I was doing last year - Creepy but Curious - is back for 2016! I kick things off this year by telling the story of the Lost Snail - a parasite call Leucochloridium which not only takes over the body of the amber snail, but also tampers with its little snail mind. So if you like hearing story about body-snatching, mind-bending parasites, follow the link here: https://soundcloud.com/abcnsw/creepy-but-curious-tommy-leung-the-lost-snail

#scienceeveryday  
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Body-Snatching A King
I have written a new Parasite of the Day blog post! This post is about a parasitic barnacle which takes over the body of king crabs. While they may look like a kidney-shaped blob trailing a bundle of green hair, they're more than meets the eye. Follow the post below to find out more!

#scienceeveryday  
If you come across a crab which has some kind of kidney-shaped blob sticking out of its abdomen and an extensive network of root-like filaments throughout its body - do not be alarmed - it is merely infected with some kind o...
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Dove, garlic
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Heart Of The Matter
I have written a new Parasite of the Day blog post! And for the first post of 2016, I have written about the lifecycle of a fish blood fluke, specifically Cardicola orientalis. This parasite has a lifecycle which involves tuna and polychaete worms - so what does it do to its hosts? Follow the post below to find out more!

#scienceeveryday  
Tunas are one of the most graceful animals of the sea. These sleek and powerful predators spend their lives in motion, cruising the open seas for prey. But despite being such formidable fast movers, this does not make them im...
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Ichthyosaur Survival Strategy
Mawaru Penguindrum is an anime series which aired during 2011 and directed by Ikuhara Kunihiko. He is also known to have directed Revolutionary Girl Utena, and more recently Yurikuma Arashi. Ikuhara is well known for using a lot of visual symbolism in his series, and Penguindrum is arguably the most visually and thematically dense show that he has directed so far.
Penguindrum is one of my favourite anime series and accordingly, my "PalaeoAnime" tribute for it is also thematically and visually dense as the anime itself. This piece covers the theme of the End-Permian Mass Extinction Event, the adaptive radiation of early to mid-Triassic marine reptiles, the evolution of the ichthyosaurs, and of course, it wouldn't be a Penguindrum tribute if it didn't involved Survival Strategy!
Mawaru Penguindrum is an anime series which aired during 2011 and directed by Ikuhara Kunihiko. He is also known to have directed Revolutionary Girl Utena, and more recently Yurikuma Arashi. P...
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What Are These? Tapeworms For ANTS?!
I've written a new Parasite of the Day post! This one is about a tapeworm that infects ants and uses them as a way of reaching the woodpecker - the parasite's final host. To facilitate that process, the tapeworm also alter the ant's behaviour and appearance, but by doing so, this seems to also affect the ant's uninfected nestmates. To find out what effects this parasite has on the ant colony as a whole, see the post below!

#scienceeveryday  
There are many examples of parasites altering the behaviour of their hosts, and some of them turn their hosts into functionally different animals compared with their uninfected counterparts. When this occurs in highly social ...
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That is the subject of ongoing research, but it might have something to do with the parasite manipulating the muscles of their ant host: http://onlinelibrary.wiley.com/doi/10.1111/mec.13498/full
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Evolutionary biologist, parasitologist
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Parasitologist, Evolutionary Biologist, Researcher, Lecturer
Introduction
Parasitologist and evolutionary biologist who also happen to write for a blog about parasites, and likes to draw things sometimes.

I am a biologist who conduct studies on various ecological and evolutionary biology aspects of parasitism/symbiosis. I also write for the Parasite of the Day blog, which I co-administrate with its founder, Susan Perkins of the American Natural History Museum.

Outside of my professional field, my favourite thing to do is drawing - some of which (but not all) are inspired by my scientific work. My drawings can be found on my dA account.
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