Darwin caricatures.

Darwin’s views are often misrepresented to the point of caricature, as we all know, but there have also been plenty of examples of literal caricature of Darwin in the popular media. I recently gave some talks about evolutionary imagery, which included popular press cartoons from the 1800s that had a common theme of caricaturing Darwin as a chimp or having non-human apes exhibiting human characteristics and behaviour. This seems like as good a day as any (the 150th anniversary of the Origin, and all) to post my collection for your enjoyment.

[album: http://www.genomicron.evolverzone.com/images/albums/DarwinCaricature/]

Are humans still evolving?

Yep, according to a study coming out in PNAS and supported by NESCent.
(As usual, the news comes out before the PNAS article is actually available, so I can’t comment on the study).

Are Humans Still Evolving? Absolutely, Says A New Analysis Of A Long-term Survey Of Human Health

Byars, S., D. Ewbank, et al. (2009). Natural selection in a contemporary human population. Proceedings of the National Academy of Sciences 106, in press.

Evolution and art.

From Oct. 9-30, the University of Guelph and Ed Video are hosting a special art exhibit entitled “This View of Life: Evolutionary Art for the Year of Darwin“. It was organized by professors in four departments: Integrative Biology, Philosophy, History, and English and Theatre Studies, and was curated by Scott McGovern of Ed Video. The exhibit features art by 10 artists, all inspired by the themes of evolution, Darwin, and biodiversity. The Gregory Lab contributed some installations as well, which are shown in this brief clip from just before the opening reception on Oct. 16 (about 200 people attended the event). The first window shows live Daphnia magna (“water fleas”) to depict the concept of overproduction; they also are of interest because they reproduce asexually (the evolution of sexual reproduction being an important question in evolutionary theory). The second window presents images created using live colonies of E. coli bacteria. These last only a few days, so many different images will be displayed throughout the exhibit. The third window shows a projection of a remarkable collection of images of bacterial colonies kindly provided by Dr. Eshel Ben-Jacob.

Here are some more photos of the artwork:

[album: http://www.genomicron.evolverzone.com/images/albums/EvolArt/]

Special thanks to everyone involved in organizing the exhibit, to the artists, and to the following graduate students who are talented artists in their own right: Joao Lima, John Wilson, Tyler Elliott, Paola Pierossi, Nick Jeffery.

Discovering Ardi — my thoughts.

I liked it.

Overall, I think the Discovery Channel did a good job of capturing the painstaking work that goes into scientific research, in this case spanning more than 15 years from discovery to publication. Some other quick thoughts:

  • This was not hype. If anything, it was pretty modest, given the amount and significance of the work involved. I didn’t see the Darwinius special, but even the previews had me wincing.
  • Mike Rowe is an excellent narrator. I have enjoyed his work when I have watched Deadliest Catch and Dirty Jobs, but I would also like to see (er, hear) him on more specials like this in the future. Mike, if you happen to read this, nicely done.
  • The special did a fine job of emphasizing over and over what needs to be emphasized over and over: we are not descended from chimps, we share a common ancestor with chimps.
  • This isn’t so significant as evidence for the fact of human evolution — we had plenty of that before. This is an important find that illustrates more about the path of human evolution.
  • I am not sure I entirely see why Ardi necessarily shows that the common ancestor was not chimp-like (knuckle-walking and large canine teeth could have been lost after the split), but I will see if this is made more clear in the actual papers. Nonetheless, no one should have assumed the common ancestor must have been very similar to a chimp — that assumption is based on a poor grasp of phylogenetics, basically.
  • The show could probably have been about 1/2 hour shorter. I enjoy seeing reconstructions, and I appreciate that they showed how this is done (I go through this briefly in one of my lectures as well, and I also liken it to forensic reconstruction). However, this did seem to imply a little more than I would have liked that coming up with a digital animation was the culmination of the work rather than an interesting aside.
  • They could have done without the just-so story about pair bonding and carrying food. I guess viewers would prefer some idea, and they did mention that there were many previous hypotheses, but if I had one significant complaint about the special it’s that this part was really speculative and not up to the standard of the rest of the meticulous research depicted otherwise.

How detailed an understanding of evolution do we need?

The folks over at Science and Religion Today were interested in our study on graduate student conceptions of evolution, and asked me to give some thoughts on the question “How detailed an understanding of evolution do we need?” Here is my answer.

If by “we” you mean “scientists,” then it is extremely important that we gain as detailed an understanding of evolutionary mechanisms and the patterns of diversification that they have produced as we can. The question of the origins of biological diversity is a fundamental one, and obtaining as complete an answer as possible is a primary goal of the life sciences. Evolution is to biology what the periodic table is to chemistry: It makes sense of otherwise disconnected pieces of information and provides the framework for further investigation.

If you mean “students enrolled in science programs,” either undergraduates or grad students (as in our study), then I would say that a good working knowledge of evolutionary theory, though not a full understanding of all its nuances, should be a major goal. Again, evolution is the unifying principle of biology, and without grasping how it works, one cannot make sense of the history and current diversity of life on this planet. Most science majors will not go on to become professional evolutionary researchers, but many will become teachers, researchers in industry or government, consultants, doctors, politicians, or any of a wide range of careers in which a working knowledge of evolution is important. As I tell the students in my course when I discuss why they should work hard to understand evolution, if the goal is to have a scientifically literate public, who but the future teachers and other educated citizens can make that happen?

If you mean “members of the public at large,” then I would say that at least a basic understanding of evolution is still important, if not for academic reasons then for pragmatic ones. Evolutionary knowledge informs decisions in medicine, agriculture, resource management, and many other areas. If, as I am sure most biologists feel, an understanding of evolution is important at all levels, then it is important that it be taught—and taught properly—from elementary school to graduate school. A population that recognizes the standing and relevance of evolutionary principles is one that will support this endeavor, whereas one that misunderstands or fears evolutionary biology will seek to undermine science education. There is an inevitable feedback loop in this regard, and effective education is the way to make it a positive one.

How detailed an understanding of evolution do we need? It depends on who “we” are—but “very little” is not the answer in any case.

Humans vs. chimps — neither is an offshoot.

Tomorrow’s Science will be a special issue reporting tons of new information on the fossil hominid Ardipithecus ramidus (“Ardi”), which is really exciting (though not as much as Darwinius, which was “like a meteor hitting the Earth” or whatever).

There are news reports of course, including one at USA Today that I want to comment on briefly:

The analysis of Ardipithecus ramidus (it means “root of the ground ape”), reported in the journal Science, changes the notion that humans and chimps, our closest genetic cousins, both trace their lineage to a creature that was more like today’s chimp. Rather, the research suggests that their common ancestor was a walking forest forager more cooperative in nature than the competitive, aggressive chimp…

[So far, so good, but then…]

…and that chimps were an evolutionary offshoot of this creature.

Nope. Neither humans nor chimps are offshoots of this creature, they are (if the phylogenetic assumption is correct) both descendants of a creature similar to this (but probably not this one per se). Otherwise it’s like arguing that your cousin is an offshoot of your grandmother and you’re not.

Luckily, one of the authors is quoted as giving a more reasonable interpretation:

So that could mean that while humans didn’t diverge much from their evolutionary ancestors, “chimps and gorillas look like really special evolutionary outcomes,” says Science study author Owen Lovejoy of Ohio’s Kent State University.

Right. This would make many of the obvious traits of chimps derived rather than primitive, and many classically human traits primitive rather than derived. (It doesn’t really matter in one sense, because every species is a mixture of primitive and derived traits, but it sure would destroy those evolutionary lineups with chimps at one end and humans at the other).

Much to no one’s surprise, Carl Zimmer presents a good story on the topic:

Chimpanzees may be our closest living relatives, but that doesn’t mean that our common ancestor with them looked precisely like a chimp. In fact, a lot of what makes a chimpanzee a chimpanzee evolved after our two lineages split roughly 7 million years ago. Ardipithecus offers strong evidence for the newness of chimps.

Only after our ancestors branched off from chimpanzees, Lovejoy and his colleagues argue, did chimpanzee arms evolve the right shape for swinging through trees. Chimpanzee arms are also adapted for knuckle-walking, while Ardipithecus didn’t have the right anatomy to lean comfortably on their hands. Chimpanzees also have peculiar adaptations in their feet that make them particularly adept in trees. For example, they’re missing a bone found in monkeys and humans, which helps to stiffen our feet. The lack of this bone makes chimpanzee feet even more flexible in trees, but it also makes them worse at walking on the ground. Ardipithecus had that same foot bone we have. This pattern suggests that chimpanzees lost the bone after their split with our ancestors, becoming even better at tree-climbing.

Chimpanzees do still tell us certain things about our ancestry. Our ancestors had chimp-sized brains. They were hairy like chimps and other apes. And like chimps, they didn’t wear jewelry or play the trumpet.

But then again, humans turn out to be a good stand-in for the ancestors of chimpanzees in some ways–now that Ardipithecus has clambered finally into view.

See also:

Does evolutionary biology make predictions?

A commenter on my other blog at ScientificBlogging (basically a subset of posts from this one) seems to have objected to the claim that evolutionary science makes predictions.

gimme 5 examples of predictions, i mean real predictions: not fit the model hogwash

Here’s a list that I put together in around 10 minutes.

1) That a transitional fossil linking fishes and tetrapods would be found in rocks of a specific age (from the Devonian) and formed in freshwater environments. CONFIRMED.

2) That human chromosome 2 would show clear signs of fusion of two chromosomes that are separate in other apes when examined at the level of DNA sequence. CONFIRMED.

3) That genes for producing features thought to have existed in ancestors but absent in descendants will still be found when genomes are examined in detail or even through atavism. CONFIRMED (see also the paper mentioned in the original post).

4) That proteins in the bacterial flagellum will turn out to be similar to proteins with other functions. CONFIRMED.

And a classic…

5) Darwin predicted that the evidence would show that humans evolved in Africa based on similarities to other apes. CONFIRMED.

Others have put together some decent videos about this as well.

Want to share your own favourite examples?

Are we descended from monkeys?

Today I gave my lecture on mammal diversity and evolution in the 4th year vertebrate course. We have been talking a fair bit about paraphyletic groups, common vs. scientific names, and so on. Within this context, we explored the issue of whether we’re “descended from monkeys”, by taking a look at a phylogeny of relevant primates:

The issues that we noted were:

  1. “Apes”, as defined as orangutans, gorillas, and chimps, but not humans, is paraphyletic. In other words, either “apes” is not a scientifically defensible term or else it must include humans.
  2. “Monkeys” is paraphyletic, and in particular Old World monkeys are more closely related to “apes” than they are to New World monkeys. (Also, humans and Old World monkeys are equally closely related to New World monkeys).
  3. We are not descended from any modern “monkeys” or “apes”, rather we share common ancestors with them. (In that sense, the answer is NO to whether we’re descended from monkeys).
  4. The last ancestor shared by all apes (including humans) would itself probably have qualified as an ape. (In that sense, the answer is YES we are descended from an ape, but not any of the modern species).
  5. For “monkeys” not to be problematic, it would have to include apes. In that sense, we would be apes AND monkeys. (And, for that matter, we’re also lobe-finned fishes). As above, it may very well be that the ancestor of all monkeys and apes (the very bottom node on the phylogeny) would have been considered a monkey, and therefore YES we are descended from a monkey (but again, not any modern species).

After class, one of my students emailed me a link to this video, which explores the issues nicely. The author takes a cladistic approach and concludes that we are descended from monkeys for the reasons listed above.

What do you think?