struthioniformes

anonymous asked:

Besides the Smilodon thing, what was so bad about that Cracked article?

Oh, boy. Take a seat, because we’re going to be here for a while.

Here is a link to the article, for those morbidly curious.

To start off, the very premise rubs me the wrong way. Evolution “ruins” things? For whom? Generally not for the organisms that are evolving. Evolution produces organisms that are adapted to the specific environmental and ecological conditions that are present at a given time. If that means being an unassuming detritivore happens to be easier (evolutionarily speaking) and more adaptive for an organism than being a large predator, so be it. The premise of the article is instead that evolution “ruins” things by not turning everything into murderkillmonsterbeasts that Hollywood would get a boner for. But the two million brown rats in New York City don’t fucking care if you think they are less badass than a mountain lion. They are thriving and prospering, resisting all the selective pressures that we are putting on them, whereas mountain lions are nowhere to be seen in the same habitat. The entire concept of evolution “ruining” things reeks of anthropocentrism and awesomebroism.

The evolution that happened in the past can suck for an organism big time if conditions change and the organism is too specialized in its previous niche to easily adapt to the new scene. Evolution has no foresight. Organisms do not evolve on the basis of “Well, it might be useful two million years in the future”, and certainly not to suit the aesthetic preferences of naked apes (which didn’t even exist at the same time as some of the “ancestral” creatures listed in the article). (Later on those naked apes did learn to simulate the forces of evolution to tailor some organisms to their personal preferences, but that’s besides the point and hardly responsible for the evolution of most organisms.)

Would you like one example of an ecological guild prone to suffering from overspecialization? Apex predators, which almost always rank high on our “awesomeness” charts. Top predators tend to require immense amounts of resources (such as food and territory) to survive, and they themselves cannot exist in great numbers due to similar limitations. And as superbly adapted for predation as they are, in most cases the majority of their hunts still fail. (A plug for BBC’s documentary series The Hunt, which shows this wonderfully.) Living on the edge as they already are, it doesn’t take much ecosystem destabilization to take them out.

So, in a very convoluted sense, the article has a point in that evolution can “ruin” things for apex predators and other spectacular, specialized creatures, but it instead approaches the phenomenon from the perspective that it’s because such animals tend to evolve into smaller and more generalized forms, which is terrible because they are less awesome now. This perspective fails on two counts, first among them that specialists do not typically go on to survive as dramatically “less badass” forms. They are simply more vulnerable to extinction in the first place. Secondly, as already explained, nature does not care if you think the evolution of smaller or more generalized organisms is “terrible”. Cry me a river.

Apex predators are undeniably awesome, in physical prowess if not in their long-term longevity. However, I find it more productive to help people find wonder in other organisms rather than to shit on everything else for not being in an unstable, easily extinguished niche.

All that is primarily my beef with the presentation of the article. I likely would not have been a fan even if all the examples it gave were legitimate, but I would have at least understood it as a vehicle for science communication. I’m not even inherently opposed to invoking awesomebro for such a purpose, which Cracked regularly does to great effect when discussing living animals. (Check out the articles by @bogleech as well.) Those were my complaints with the “communication” in science communication, if you will. Let’s move on to the “science”, and the scientific errors in the article are legion.

One irritatingly pervasive thread throughout is that the article purportedly discusses ancestral species and their modern descendants, but almost none of the examples it provides even comes close to being an actual ancestor-descendant relationship. I don’t even mean in the paleontological sense of “it’s almost impossible to demonstrate direct ancestor-descendant relationships in the fossil record, so we should be cautious about applying the ‘ancestor’ label to anything“. In none of the entries do the supposed ancestral species even morphologically approximate the immediate ancestors of the supposed descendant species. In most cases the supposed descendant is not even a particularly close living relative of the supposed ancestor; sometimes the “descendant” is not even among the “ancestor’s” closest living relatives! I used the word “even” a lot in that paragraph, because it’s that egregious.

It would perhaps be most efficient for me to elaborate on each entry in the order they are presented, with asides on other flaws as I encounter them.

1. Hyaenodon to raccoons
Hyaenodon was a creodont, a group of carnivorous mammals from the Paleogene and Neogene. The exact phylogenetic position of creodonts is not entirely certain (in fact, it is not clear that creodonts all form a distinct group closely related to one another), but they are traditionally considered to be closely related to carnivorans. Raccoons are carnivorans, so the comparison may appear justifiable… but so are big cats, hyenas, wolves, bears, wolverines, and other stereotypically badass animals. That mention in the article about how creodonts may have been outcompeted by other predators? Those other predators were mostly carnivorans, as closely related to Hyaenodon as raccoons are. There is no reason to link raccoons specifically to Hyaenodon, unless someone meant to use the most mundane wild carnivoran familiar to the general American populace possible. It’s almost like the fixation on comparing non-avian theropods with chickens… which, likely not coincidentally, shows up right in the opening passage of the article.

Interestingly, a recent study suggests that creodonts are most closely related to pangolins, which is not as big of a leap as it might initially seem considering that pangolins are the closest living relatives of carnivorans.

The article also implies here that Velociraptor was cold-blooded, in comparison to the warm-blooded Hyaenodon. What is this, the 1960s? For those unaware, it is very, very likely that non-avian dinosaurs had some form of elevated metabolism. To add insult to injury, they used Velociraptor specifically, one of the most bird-like of the “traditional” dinosaurs, and thus one of the least likely to have had a wildly divergent physiology from birds. (There is some evidence that modern birds do have a “supercharged” metabolic rate compared to other dinosaurs, including most Mesozoic birds, but that still by no means makes other dinosaurs ectothermic in the sense of most non-avian reptiles.)

Lastly (for this section), there is to my knowledge no direct evidence that Hyaenodon hunted in packs.

2. Gastornis to “struthioniforms”
The term “struthioniform” is now restricted to ostriches, but the article appears to be using it for all “ratites”, the (mostly) large flightless birds of the Southern Hemisphere (which are now known to have lost flight independently of one another and thus no longer considered a natural group, but all of them being paleognaths, they are still reasonably closely related to each another). That’s understandable, given the age of the article. What’s less understandable is why “ratites” were brought up at all, given that Gastornis is generally considered to be more closely related to… ducks.

Mind you, Gastornis still wasn’t approximating the actual ancestry of modern ducks. It was more like a bizarre extinct branch with no modern descendants (like essentially all the other prehistoric creatures listed here). However, the article would have at least been more accurate and produced better material had it linked Gastornis to ducks. I think ducks are pretty rad, but surely it would have been easier to make fun of them than of some of the few birds in the world that have been confirmed to kill people. Even the small and secretive kiwis are among the few New Zealand birds that can sometimes hold their ground against invasive predators. Notice also that the most notorious of the “ratites”, the cassowary, is not mentioned at all.

Contrary to the article’s claims, Gastornis lived and died in the Eocene (45 Ma), long before the last ice age (beginning about 2.58 Ma).

By the way, convincing research published after the article was written suggests that Gastornis was primarily a herbivore rather than the mega-predator that it is traditionally depicted as. I imagine that, like an ostrich or cassowary, it still wasn’t a bird you’d want to cross though.

3. Smilodon to marsupials
I will try to keep this brief considering that it was awareness of this inaccuracy that sparked the ask in the first place, but this one is easily the worst entry of all, given that it doesn’t even talk about the right prehistoric animal that it meant to. Smilodon, the classic saber-toothed cat in pop culture, though not a tiger, was a true cat (or to be more precise, near enough to modern cats that no paleontologist minds calling it a cat, at least to my knowledge). However, it and its kin were not the only saber-toothed predators in prehistory. Thylacosmilus was a saber-toothed probably-not-quite-a-marsupial-but-close-enough, and it was almost certainly this creature that misled the author of the article.

4. Megatherium to tree sloths
This otherwise terrible article shows that it has some vestiges of mercy by following up on that godawful previous entry with the one with the fewest issues. Megatherium was a true sloth. It was not a direct ancestor of modern sloths, but what else is new?

The article does not specify which group of living sloths (two-toed or three-toed) it postulates as descendants of Megatherium, though by chance(?) all of the images and clips are of three-toed sloths. This may not sound like a big deal until you remember or learn one of my favorite sloth facts, that the two living groups of sloths are not particularly closely related to each other!

Three-toed sloths appear to be the outgroup to all other sloths. (In other words, all other sloths are more closely related to each other than to them.) Their fossil record is not very good, but given that the closest living relatives of sloths, anteaters, are mostly tree-dwelling (except for the one species most people happen to be familiar with), it is plausible that the common ancestor of anteaters and sloths, and in turn the early members of the three-toed sloth lineage, were already hanging out in trees.

The various groups of ground sloths (including Megatherium and its kin), on the other hand, were all more closely related to two-toed sloths. In particular, two-toed sloths appear to belong to a group of sloths called Megalonychidae, which mostly includes fully or partially terrestrial forms. So the ancestors of two-toed sloths appear to have been ground sloths that made it back into the trees to live similar lives to their three-toed cousins.

The notion that Megatherium habitually ate meat is… fanciful, at best, but at least it was suggested in an actual scientific paper.

5. Entelodon to pigs
This connection is at least a reasonable one for its time. Though (once again) not the direct ancestors of pigs, entelodonts really were thought to be closely related to them for a long time. However, the most recent phylogenetic analyses that include them suggest that entelodonts were closer to hippos and whales.

I won’t get on the article’s case for not being able to predict the results of future research, but I will for its portrayal of pigs as the “lame counterparts” to entelodonts. Its entire description of pigs centers around domesticated breeds that were artificially selected by humans. Wild pigs, especially the wild boar that domestic pigs were bred from, don’t take crap from anybody.

There is to my knowledge no direct evidence that Entelodon traveled in groups, nor that it defecated on carcasses to dissuade other scavengers. That sounds suspiciously like speculative behavior shown in Walking with Beasts… but there it was a Hyaenodon that defecated on its kill to try and deter some entelodonts.

6. Andrewsarchus to goats
Science marching on has hit this one hard as well. Andrewsarchus was traditionally considered a type of mesonychian, a group of carnivorous hoofed mammals from the Paleogene. Mesonychians were traditionally considered closely related to whales. However, it turns out that whales are more closely related to hippos, whereas some analyses suggest that Andrewsarchus was not a mesonychian but a close relative of entelodonts, which are now thought to be close to hippos and whales. True mesonychians are generally found to be equally closely related to all living hoofed mammals, both the even-toed artiodactyls and odd-toed perissodactyls (though a recent study, the same one mentioned in the Hyaenodon section above, found mesonychians to be even more closely related to carnivorans). So Andrewsarchus was once thought to be a mesonychian and thus close to whales, but whales are not, in fact, close to mesonychians; however, Andrewsarchus may actually be closely related to entelodonts, which would make it closely related to whales! Are you confused yet?

Luckily for our purposes, the article was written in 2008, before most of this phylogenetic craziness happened. Let’s see how things check out against the general consensus of the time, that Andrewsarchus was a mesonychian. The whale-hippo relationship was recognized by this point for most part, and mesonychians were considered to possibly be closely related to artiodactyls.

Goats are artiodactyls, yes… as are pigs, camels, giraffes, deer, cattle, antelope, hippos, and a whole host of others. We’re running into the same fallacy as the Hyaenodon-raccoon link. There is nothing special about goats that connects them to Andrewsarchus exclusive of all the others. One could just as easily write an article about how the “descendants” (ugh, I can’t do it even with scare quotes) closest modern relatives of mesonychians include some of the biggest “badasses” in the animal world, because if you know anything about certain artiodactyls such as hippos and African buffalo, you know that they are scary as shit. And if you still think those are just a bunch of dopey herbivores, I’ll raise you one better: one of the most terrifying predators of the sea is an artiodactyl, the orca.

Because if you hadn’t known or figured it out by now, whales are also artiodactyls. (And for the sticklers who will point out that orcas are dolphins, dolphins are phylogenetically a type of toothed whale.) Considering the historical precedent of putting mesonychians close to whales, it would have been far more meaningful (if not entirely accurate) to highlight that connection instead.

Like Gastornis, Andrewsarchus lived in the Eocene, not anytime close to the last ice age.

Whew! That took much, much longer than even I had intended. Congratulations if you made it all the way to the end. One final thing I’d like to say: please do not send me requests to do in-depth critiques just because I did this once. I typically do not have time for these. I did one for this article because it was really, really bad and I had not seen anyone else provide such detailed critique on it.