\ Visualizing Evolution: May 2008

Thursday, May 29, 2008

Frogamander vs. Crocoduck!

Allow me to rant for a moment. I love listening to science podcasts, especially ones focusing on skepticism, but there have been a couple of irritating mistakes in the last week. It's also possible I'm getting uptight over nothing and being the evolutionist equivalent of the dreaded Grammar Nazi, but anyway...

The first offense was on the May 7 episode (#146) of the "Skeptic's Guide to the Universe," in which host Steven Novella was discussing transitional fossils and mentioned Confusciusornis, one of the feathered dinosaurs of China, referring to it as "a beautiful half-reptile/half-bird." He then made it much worse by reinforcing his idea with the phrase "it really is LITERALLY half-bird and half-reptile." I was irritated, but after some calming tea, I eventually got over it.

But then today I was catching up on "Skepticality," (episode #078) and host Swoopy, in referring to the fossil amphibian Gerobatrachus hottoni said the following:
"...and in Texas, a part-frog/part-salamander is the only fossil found to shed new light on how amphibians evolved into two separate species."
First of all, the fossil represents a possible common ancestor of frogs and salamanders, not some sort of frogamander hybrid, and second of all... two separate species? Living amphibians include three orders: Salientia (frogs and toads), Caudata (salamanders), and Gymnophiona (caecilians), each of which contain many, many, species. Picky? Maybe. This could just be an example of a poorly-phrased remark, and I'm sure Swoopy knew what she meant to say, but there's a point to my rant, so stay with me here.

At least they got it right on the notes section of their website for the episode:
"Just this week, the discovery of the 300-million year old Gerobatrachus hottoni ("Hotton's elder frog") confirmed the previously contentious inference that modern frogs and salamanders evolved from one group of ancient primitive amphibians. The dispute arose because of a lack of transitional forms; but, like so many "missing links," this newly discovered fossil sealed the gap."
If we want people to accept evolution, they have to understand it. We must avoid this confusing language! The missing link between A and B is not "half-A/half-B"; that's not how evolution works! And saying it that way is misleading and confusing and yet... oh, so common.

It's no wonder the Kirk Camerons out there are saying fossil evidence for evolution would have to include something like the Crocoduck:


Well, then.

To anyone who has studied and understands evolution, this is, of course, ridiculous. But look at it from the point of view of someone without that education and imagine hearing a news report about a frogamander or dinobird and it becomes clearer how people can become confused and decide to discard the idea of evolution entirely.

Bonus reconstruction of Gerobatrachus hottoni! (From the NGS article)


Even the National Geographic article (linked above) calls the creature a "Frog-amander," and comparative biologist Jason Anderson said of it:
"It had an overall amphibian gestalt...you know, kind of a froggy salamander-y sort of look... so it's kind of a frogamander, if you will."
But he also remarked:
"It pretty convincingly settles the question [that the] frog and salamander shared origins from the same fossil group."
Evolution of course predicts the existence of just such a fossil, but it's so important to keep in mind that a common ancestor of A and B won't necessarily look like an A/B hybrid. Take our common ancestor with chimpanzees, which was most certainly more chimp-like than human-like. We can't accidentally lead people to think that evolution occurs in a manner I once heard referred to as "Pokemon style evolution" in which individual organisms just kind of morph into something else.

It also reminds me of the Nickelodeon cartoon "Avatar: The Last Airbender," in which every animal species is a combination of two or three other things. Platypus bears. Saber-tooth moose lions. Lemur-bats. Rhino-lizards. In fact, the characters became confused upon finding out that the Earth King owned a bear.
Katara: The King is throwing a party at the palace tonight for his pet bear.
Aang: Don't you mean platypus bear?
Katara: No, it just says, 'bear'.
Sokka: Certainly you mean his pet skunk bear?
Toph: Or his armadillo bear?
Aang: Gopher bear?
Katara: Just, 'bear'.

(short pause)

Toph: This place is weird.
So unless we're talking about actual hybrids like ligers and camas (so cute), let's leave our half-and-half animals in the land of fantasy and talk about a reality of missing links and shared ancestors. It's actually much more interesting that way, anyway.

(sabertooth moose lion picture courtesy of AvatarSpirit.net)

Tuesday, May 20, 2008

"cdesign proponentsists"

Another video from Expelled Exposed, and the people at the National Center for Science Education, this time on the evidence demonstrating that "Intelligent Design" is in fact Creationism and not science.

No illustrations this time, but I'm sharing it, anyway.

Thursday, May 8, 2008

Time for some fish evolution comics!

I love Cectic and I love Tiktaalik. Therefore, I love this cartoon:
And as long as we're looking at cartoons about the missing link between fish and tetrapods......both by the amazing Gary Larson, of course, who I really wish would come out of retirement. Aw, what the heck, one more: (from Perry Bible Fellowship)
There will be a post later about iconic images of evolution, one of which is the lobe-finned fish triumphantly crawling out of the water. And for some reason, it always seems the fish is drawn with water to the left and land to the right. Speaking of Tiktaalik, here's a non-comic example from the NY Times article on the find:
Left to right, again! The same is true of the common March of Progress drawings, which always show a man walking towards the right followed by a procession of his more and more hairy and hunched-over ancestors. I don't think this is a coincidence. After all, any time you draw a timeline, the past is to the left and the future to the right. And in this culture at least, we read from left to right. So it only makes sense that evolutionary progression should be drawn left-to-right, as well.

I almost forgot Ray Troll!

Wednesday, May 7, 2008

German cladogram illustration

I had to share this beautiful example of an illustrated cladogram:
(click for big)
Unfortunately, I have no idea where it came from or who drew it. The blog I found it on said it was from "some German website." And they wonder why we illustrators and artists are so afraid of the Orphan Works Act?

Anyway, the meaning of the illustration is pretty clear even if the viewer doesn't know German--which is a sign of a good drawing and also for the usefulness of illustrations as a whole. The monochromatic color scheme and the sharp, clean lines of the drawing are unique from what cladograms of this kind usually look like. There's a lot of information packed in, but it's not visually overwhelming or 'busy.'

If anyone knows where this piece comes from, please let me know.

Update! The poster comes from a German science publishing house in Stuttgart called Schweizerbart and is available for purchase. Might have to buy one if they ship internationally. Thanks to Chucker for helping me track them down.

Tuesday, May 6, 2008

"Creationism Disproved?"

The National Center for Science Education has released another video, this time on the evolution of the eye. I really hope they make more of these. A short, accessible video that is thorough without being overly complex--perfect to send to that non-science educated person who has been told that the eye is an example of "irreducible complexity" and thus disproves evolution.
Intelligent design proponents say the eye is too complex to have evolved. The scientists in this video say, "Look at the evidence."

The video uses some nice illustrations, but it's too bad someone couldn't throw together a Flash animation of the process they're talking about. (No, I'm not volunteering ... well, maybe if they asked nicely...)

Other video critiques by the NSCE of intelligent design can be found here.

Friday, May 2, 2008

Illustrating Convergent Evolution

Today I'd like to point you in the direction of a blog by paleo artist Carl Buell (a.k.a. Olduvai George) who has a great entry from February of 2006 on Illustrating Evolution. He doesn't blog much anymore, but take a look at some of his work. This is an illustrator who knows how to use Photoshop to its full artistic potential.

This painting from the "Illustrating Evolution" blog, which depicts the extinct marsupial Thylacine along side a Dingo, demonstrates his main point in the article.
"Although we talk all the time of the incredible diversity of life on our planet, that diversity is really an amazing amount of variation on a relatively very few themes."
The evolutionary idea that similar selective pressures can produce similar-looking organisms with very different ancestors (also known as convergent evolution) is one of the easiest concepts of evolution to illustrate visually. All it takes is a piece like this. Two dog-like mammals, one a placental mammal and the other a marsupial.

Actually, this type of convergent evolution is evident several times in the separate evolution of placentals and marsupials:
Mammals are a good place to start thinking about convergent evolution, but examples exist throughout the animal kingdom (and probably plants too, but I can't think of an example just now).

Take dolphins, sharks, and Ichthyosaurs, for example. All three are pursuit-hunters of fish, relying on speed and streamlined bodies to survive, and despite starting off with very different looking ancestors, (a mammal, a fish, and a reptile) all ended up with torpedo-shaped bodies, paired triangular pectoral fins, a single triangular dorsal fin, and double-lobed tail fins.
Aso note that the main difference in locomotion, namely the up-and-down motion of the tail in dolphins, which differs from the side-to-side motion in sharks and Ichthyosaurs, is due to the parasagittal gait evolved by early mammals. The therapsids (which include modern mammals) changed their locomotion from a side-to-side motion of the spine to an up-and-down motion when they started walking with their limbs directly under their bodies. Think of the way an alligator runs compared to a greyhound and the distinction should be clear. And though the dolphin evolved back to something shaped rather fish-like, it retained this style of spinal motion!

Thursday, May 1, 2008

The ID Pyramid Scheme

I can't take credit for the idea, but I thought it was brilliant and deserving of graphical representation: