Illustrating Evolution (1)
Evolution is a simple fact of life. Every time I start drawing another animal common descent screams at me. It’s really the only thing that makes drawing and painting extinct creatures at all possible. 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.*
We admire and envy the flight of an eagle. We are astounded by the speed and reactions of a cheetah. We see a dolphin flash through the water seemingly as fluid as the liquid surrounding it. We see perfection.
But I would argue we have no way of knowing what perfection would be. We only have what is. And what I see is a world of jerry-rigged creatures formed mindlessly by evolution on a limited number of body plans, with only the variation within each generation as raw material. As products of evolution they are astounding. Considered as the supposed result of independent creation, they are amazingly devoid of novelty, imagination or inventiveness.
Devonian Lobe-finned Fish, Eusthenopteron
1.
Before the first backboned creature ever crawled out of a Devonian swamp the basic body plan of all terrestrial vertebrates was established. Every amphibian, reptile, bird and mammal carries in their genes that morphological baggage. In mammals for instance, the same set of bones inherited from their reptilian and amphibian antecedents is responsible for (and has been warped into) the wing of a bat, the flipper of a whale, the foreleg of a horse, and my own arm. At the same time, that genetic “baggage” limits the forms vertebrates can assume and gives us the concept of convergence.
Working on any vertebrate, nothing I draw is ever completely novel. Genetic, ecological and physical restraints keep the vertebrate body coming back to a few optimally functional forms.
Thylacine and Dingo
2.
For a larger, more detailed image click on this red type
Here we have a recently extinct, marsupial Thylacine (3.) and its ecological equivalent (and replacement in Australia), the Dingo, a placental canine carnivore. These mammals have had separate evolutionary histories since at least the early Cretaceous. Both are the descendants of little insectivorous creatures that lived in the shadow of the dinosaurs. So are aardvarks and elephants, but in this case both these creatures evolved to do the same ecological task. And apparently the best functional form for a cursorial mammalian predator is “doggish”. Certainly not perfect, just good enough. Given a conscious, involved designer there’s no reason for that to be so, but evolution can’t just invent new gadgetry out of nothing.
Early Flesh-eating Ungulate, Pachyaena
For a larger, more detailed image click on this red type
This is one of the smaller, more gracile species of genus Pachyaena and it was doggish in the early Eocene long before anything that could be called a canine was around. Pachyaena was a Mesonychid, a flesh eating ungulate with small, spatulate hooves, a relative of the artiodactyls, represented today by cattle and deer, camels and antelope, hippos and pigs.
All too often I hear narrators on the National Geographic, Discovery or Animal Channel refer to one creature or another as perfectly adapted to their environment. Perhaps since a species can last a long time and fit well into an ecosystem, that statement seems close to true, but individuals are evolutionary fodder. Each animal lives on the edge of the precipice, one misstep away from disease, injury and death. All that matters is that enough members of a population reach breeding age and parent the next generation.
It can be depressing if you dwell on it, and indeed, there’s always a touch of melancholy present as I marvel at the natural world. But if anything, their imperfection makes the individual creatures I portray that much more beautiful and all that more endearing to me because I know the absolute indifference they face in their world; a world without the medical and technological insulation we surround ourselves with.
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* Since my career has overwhelmingly involved the depiction of vertebrates, I use them for my examples. I certainly mean no disrespect to other phyla, and it’s no doubt true that vertebrates are simply a very thin and showy frosting on the cake of life.
1. This illustration is one of many I did in 1997-98 for Carl Zimmer’s book on two of the major transitions in the history of life, At The Water’s Edge.
2. For another look at both the similarities and differences of these two animals, read this great December post by Martin Brazeau at The Lancelet.
3. For an absolutely wonderful site full of information on Thylacines, including films of the last surviving individuals in captivity click here!
February 21st, 2006 at 3:49 am
I had something for Thylacines since I was a little child. I was as happy ‘as a puppy in an elevator’ when someone posted the link to that Thylacine Museum website a few months ago on Pharyngula. The movies almost made me cry. The text made me angry. Now your drawings make me happy.
February 21st, 2006 at 9:49 am
A flesh eating ungulate - now that’s cool!
February 21st, 2006 at 9:58 am
Thanks, Carl.
February 21st, 2006 at 10:01 am
I would like to make you know that i come here averyday (true!) and love your work. Thanks. Paulinho.
February 21st, 2006 at 10:22 am
coturnix,
Thylacines never really showed up on my radar until the museum. Watching those movies was really an eye-opener for me. The similarity to dogs was obvious from photos (and from Carl’s excellent illustrations,) but watching them move — that really brought home their marsupial ancestry. As Carl notes, evolution can only work with what it’s given and even with convergent evolution, the evidence of an ancestral split prior to the convergence is seen in the differences. I see a lot of kangaroo in the the face, the tail and the rear legs of the thylacines in those films. It is amazing.
February 21st, 2006 at 10:24 am
PS, I meant to include a link to the films.
http://www.naturalworlds.org/thylacine/films/java/thylacine_films_java.htm
February 21st, 2006 at 11:07 am
Thanks Carl!!! I wish I had these when I was teaching!
Steve
February 21st, 2006 at 11:37 am
Very good delivery of a strong argument against creationism. Also a great portrayal of the usefulness of good scientific illustration. I’m looking forward to seeing more of these posts in the future.
February 21st, 2006 at 11:44 am
I have to get better at this linking business. Craig and Coturnix: the very last of my footnotes contains the link to the “Thylacine Museum”. It is truly a marvelous site. The films are wonderful and sad to watch at the same time. I kept rerunning the first and 3rd films as I was drawing and painting the animal. It made it hard to believe they’re all gone; but then Pachaena “feels” alive to me too.
February 21st, 2006 at 11:48 am
I remember the first time I saw photographs of Thylacines in an anthro class in college 20 years ago. I was hooked. It was introduced as the marsupial wolf. We were shown those films of the creature pacing and pacing in its cage. Now, I would just love one to show up like the Ivory-Billed Woodpecker, because it is such a huge loss that they no longer walk on this earth. I did a post about Thylacines a while back: Thylacines
February 21st, 2006 at 12:13 pm
Thanks for these great illustartions and your wellthoguht out commentary. I expect your work inspires a few kids to dig deeper into evolutionary biology, paleontology etc. that must feel pretty good.
February 21st, 2006 at 12:16 pm
If it ain’t broke, don’t fix it. That pretty much summarizes how evolution works, from my perspective. Evolution doesn’t have any drive towards optimal design, and it shows. It’s easier to improvise a dog out of rat than it is to create an optimal form from scratch. If ID were true, we wouldn’t be seeing legacy flaws.
I like the marsupial wolf. Wish they’d pull an Ivory-Bill, too. I doubt it’ll happen, though.
February 21st, 2006 at 1:09 pm
Thank you for the marvelous illustrations and the Thylacine Museum link is excellent. Among the many things I found fascinating was that in the 5th film clip, the Thylacine never used its front paw to hold the meat in place.
February 21st, 2006 at 3:15 pm
A flesh-eating ungulate! Who would’ve thought?
February 21st, 2006 at 7:39 pm
Greetings from a fellow illustrator. Got a real kick out of your blog here. Especially enjoyed this article, as well as your procedural breakdown of the pachyderm piece.
Scientific illustration is one of those things I’ve always wanted to get into, but I think my loose style would probably be a bad fit for that market.
February 22nd, 2006 at 3:06 am
I wonder if thylacines had the same stride as a dog. Sure, the limbs, if a little stubby (which you captured wonderfully) were close to those of a dog. It’s tempting to assume that they moved the same way.
However, they could and did assume a bipedal position. In addition, the rear limbs could go plantigrade.
Most un-canine.
My point is that while thylacines are a textbook case of convergence, and rightfully so, there was much about them unique, novel and lost forever. Certainly they were like canids in many ways, but it would rob them of their legacy to reduce them to marsupial dogs. I think your picture does a good job of getting across the dog-ness of the thylacine, as well as the subtle un-dogness.
February 22nd, 2006 at 4:16 pm
In doing the research for this I could find no photos or movies of the thylacine running so I had to go from verbal descriptions. Wild dogs like dingos, and wolves and coyotes run in a rotary gallop; the footfall being right front, left front, left rear, right rear (a few, as in humans, lead with the left). The description of a thylacine running was that it looked much like a dog, but with a little more bounding motion. To me that meant the same rotary gallop, but with the footfall of the front pair of feet closer together than with a dog, and the hind pair closer together, with proportionally more distance between the front and back sets.
Dog being R L L R R L L R Thylacine being RL LR RL LR both in a rotary motion.
As one of those wonderful films on the Thylacine Museum site shows and (neutrino_cannon) notes, thylacines could also assume a plantigrade bipedal position. While being doggish, I NEVER meant that thylacines, or even old Pachyaena, were not unique and beautiful forms, I hope that too shows in the art.
February 22nd, 2006 at 11:25 pm
Once again, I’m reminded why I love this blog. Your artwork is gorgeous like always, and your article and link was most insightful. I’d heard of the Thylacine museum before but lost the link, and I’m glad to have gotten it again. Keep up the terrific work!
February 23rd, 2006 at 3:00 pm
Your introduction to this post introduces no new ideas to those of us who get off on the wonders of natural history, but your “we only have what is” paragraph is splendid all the same. Thanks for yet another excellent read, you gifted SOB!
February 23rd, 2006 at 6:12 pm
It is so heartening to read the thoughtful, elegant prose that accompanies your illustrations. The thylacine is a symbol of so many things: extinction, convergent evolution, and more. And it’s fascinating to be reminded of the shared roots of all mammals, even all vertebrates. Bravo.
February 24th, 2006 at 3:20 am
Great post! You’re starting to sound a bit like PZ Myers
February 24th, 2006 at 12:14 pm
I happened to have found another Thylacine link, for those who may be interested. This one from the Australian Museum proper. It’s not as in-depth as The Thylacine Museum, but it has it’s interesting points.
http://www.austmus.gov.au/thylacine/index.htm
March 2nd, 2006 at 12:15 pm
http://www.sciam.com/article.cfm?chanID=sa003&articleID=000A07DF-3C56-13FE-BC5683414B7F0000
In the field of really old mammallian carnivores some get real old. Unfortunately, the article I linked to above does not say if the animal was a placental or marsupial animal. Or even a monotreme, multitubuculate, or a triconodont. All that is said is that it is a mammal.
If it is a eutherian (placental) mammal it’s most likely an early condylarth. Known early Jurassic primates were arboreal, and groups such as creodonts, carnivores, and ungulates were post Jurassic. And which type of condylth it might be isn’t stated, probably because we don’t know enough about Jurassic condylarths to make a definitive identification
One thing we do know about condylarths is that it was not a monophyletic group (like snakes), but a paraphyletic group (like thecodonts). That is, a grabbag of beasties lumped into a single group because they just happen to have similar features. (Such as the way teeth are set into the lower jaw. BTW, did you know that humans could be classified as thecodonts?
)
So the Jurassic otter-beaver might be a eutherian. If a eutherian most likely one of the condylarth groups. Which of the groups we now call ungulates is anybody’s guess. Or it might be part of a condylarth group ancestral to creodonts or carnivores, though not everybody agrees that those two groups are descendent from condylarth ancestors.
To complicate the history of ungulate carnivores, keep in mind that such as pachyaena are now considered an omnivore, and more a late condylarth than an early ungulate. Even the later mesonychids are thought to be more scavengers than active predators.
As for the short legs of the thylacine and pachyaena, that is a forest trait. True coursing animals evolved on open grasslands; a condition not really possible until the spread of the grasses around 55 million years ago. Forest dwellers need mobility more than speed, so short legs had an advantage. It’s also harder to work up a good head of speed what with trees and bushes, and deadfall in the way, so predators didn’t need to work up a good head of speed either. Now add in that fact that before the appearance of widespread grasslands forest and brush could spread farther than they can now. In short, forest and brush tended to be more varied and more open than they are now. It meant that on the average ancient forests had a greater carrying capacity per square mile than they do know. All this coming together to mean that catching prey was a lot easier back then.
You’ll note that the only short-legged groups of predators (bears, mustelids, etc) are forest dwellers, and for the most part omnivorous. The same holds true for short-legged felids and canids, such as the clouded leopard or east Asia’s racoon dog. The advanced carnivores, cats and dogs, are log-legged animals, indicatitng an origin out on the grass lands.
Finally, to bring this lengthy comment to a close, keep in mind the Earth did have a substantial, even dominant group of bipedal predators. A group which ranged from the Late Permian to the end of the Cretaceous, and which has been placed in at least two orders, and which just might warrent a third. This group belonging first to the late pre-saurischian thecodonts, then to the saurischian dinosaurs. And the last few genera may someday be listed among aves.
March 3rd, 2006 at 3:37 pm
Chris told me about your dog–I’m so sorry.
March 4th, 2006 at 4:46 am
Hello! I’ve been reading your blog since you started — your art is beautiful!
I read at Phyrangula that Tito had passed away, and wanted to send you my condolences, and let you know you and Tito are in my thoughts. He sounds like he was a lovely dog.
March 10th, 2006 at 7:31 am
I’m really Impressed constantly with your wonderfull work. And may I say I admire people who develop such strong bonds with their pets, as I am, at 21, too young to have achieved such a bond. Comisserations on the loss of your dear dog.
Your portrayal of the thylacine is almost perfect In my eyes. The big problem with most illustrations of Thylacines is that they portray it with yellowish, dingo like fur, when in reality they possessed a gray-brown pelage as a background to their stripes. This is a common trip up on the fact that most specimens of thylacine skin are sun or light damaged from years of display, properly preserved skins show it’s true colour. So I’m saying that I haven’t come upon such an accurate colouration of thylacine pelage, In a general atmosphere today that the urban-myth guise of the thylacine portrays it differently to what it really looked like.
Kudos to you sir!
Tim
April 20th, 2006 at 12:16 pm
After taking Marshall Vandruff’s first-rate animal drawing class last year, I was amazed at how similar all the vertebrates are - “Why, this thing on a snake is identical to that thing on a lion, just thinner!” and “This thing on a gorilla is idential to that thing on a bird, just heavier and wider!”
What really struck me in that class however, was how very very strange - almost hideously distorted - the human design is compared to most other vertebrates - that weird gigantic skull, that strange bipedal stance, very, very odd.
Love your blog.
August 9th, 2006 at 5:34 pm
Today I was out in the garden and saw a hummingbird moth. I immediately remembered this post.
February 2nd, 2007 at 4:48 pm
…facinating stuff! I’m doing a thing on animal distributions, involving land movements and consequent evolution therein.
What do I do when I disagree with the ‘Time Scale’ we mostly use now? It sometimes doesn’t jive, and I don’t have the credentials to even have anyone listen? -Some concern “land bridges” then & now.
Lifeforms & Rocks have WAY different ‘aging’ processes, for instance.
…going against the grain, 3d