Evolution's got a P.R. problem

People aren't just anti-evolution, evolution-averse, or pro-"teaching the controversy" because they're clinging to supernatural explanations that help them identify with a tribe. Culture is mighty powerful but it's a lot more complex than stubborn beliefs in the supernatural as deciphered from, and reinforced by, an ancient text.

Evolution's got a public relations problem that spans beyond fundamental Creationism. It's not exactly looked upon favorably by many non-fundamental yet kind, open-minded, and educated folks either! Here I've jotted down a few thoughts about why...

1. Who cares about evolution? Sheesh, what's the big deal?
Evolution doesn't appear to matter to so many people. And getting frothy over evolution can certainly spark interest but it can also, in gut reaction, intensify the apathy. We love to go on and on about how "human" it is to wonder where we came from or to wonder how the world works. Well, it's not exactly a species-wide phenomenon, at least acting on that wonder isn't. With these folks, we can just keep doing what it is that we do and hope that they will come around to see why evolution matters and hope that until then they don't influence others to be as tuned out or turned off.   People are less likely to voice apathy about knowledge that they're accustomed to like biology, history, chemistry, geology, physics, literature, English, composition, mathematics. I think this attitude about evolution will go away once biology becomes a synonym for evolution in K-12 classrooms and beyond. 

2. Mystery is mystical by default. 
It's still acceptable to fill-in ignorance about biology with the supernatural. This is not as much the m.o. with chemistry or physics, but we tend to do it there too (like with quantum mechanics). I couldn't explain how the Internet works but I assume it's not magic and I don't know anyone who thinks it is either. Yet, missing pieces of understanding in biology are not, as default, just missing pieces of understanding. We jump automatically to magical thinking rather than assume that we just don't know and that maybe someone already does! Unfortunately, gaps in our biological knowledge don't always spark us to take more classes, to read, or to watch videos to see that many of those mysteries aren't mysteries to anyone who's studied them. Gaps in our knowledge don't always spark us to undertake controlled observation or to devise experiments at home. For some reason, instead... and I think it's the Bible and other powerful cultural influences, and also the way that the history of science unfolded ... biology's mysteries are comfortably cloaked in magic. If biological mystery is mystical, then it's easier to uphold allegiance to Creationism, or to maintain intellectual empathy with fundamentalists who ask that we simply "teach the controversy." 

3. It takes quite a bit of study, observation and life experience to understand evolution. 

Evolution is a complex, multi-disciplinary matter that few people can master in one semester of study. You need anatomy, physiology, genetics, behavior, comparative anatomy, zoology, ecology, geology, history, math, philosophy, etc. But you need only dabble a few toes in those areas to begin to form the picture. Because the e-word is so often left out of K-12 classrooms, students don't realize that they're learning it all along, in all its bits and pieces as they advance year to year. When they finally do get to a classroom that uses the e-word, they think it's a whole new subject matter and that's actually quite an obstacle. Plus, that evolution takes a while to understand in any sort of useful way means we have an under-informed population full of people who, at best, had one year of solid evolutionary exposure in high school...one year of learning our one natural explanation for all of biology. That's evidently not enough to bring everyone far enough along to overcome #1 and #2. 

4. Evolution's not even well-understood by those who claim to. 
It's not. There's a lot we don't know about evolutionary history, about how it unfolded, and that means there's a lot that we are earnestly trying to figure out. And it's clear that public patience for science is lacking and that's rooted in a lack of appreciation for how science is done, how knowledge is formed, and how the truth changes. On the one hand there are those who know full well that feeble, foibly humans are devising this knowledge and on the other hand are those who've got far too much respect for "KNOWLEDGE." (The latter is revealed on the petrified faces of my students when I announce they're "creating knowledge" by doing a laboratory assignment.) Both perspectives are working against science every time something pops up in the press as being "debated" or "overturned." Every piece ends with "more research is needed." No wonder patience is running thin. The skeptics think science is fraught with fraud because it's done by people. The others flirt with thinking (or do literally think) that knowledge comes from on high, or from Revealed Natural Truths, and not possibly from mere humans. And then there are those who study evolution who are not earnestly trying to  understand it better. They're using a half-baked tool that they call "evolution" to do their work or to advocate for evolution education. And often when their views get in the popular press they're parroted or presented uncritically by writers with an equally non-nuanced understanding of evolution, who are equally oblivious to it. 

5. Evolution is being pushed by so many unhuggable atheist intellectuals. 
This has to do with what many public intellectuals like to call "tribalism" and in-group, out-group identity. Aligning yourself with professors or intellectuals is social and political suicide for many. Aligning yourself with the godless can be even worse. Of course there are lots of folks who retain their beliefs and accept evolution, but there are fewer of them (at least in the limelight) than us who eschew or reject the supernatural.  We need more huggable atheists. We need more huggable intellectuals. We need fewer anti-intellectuals. We need fewer anti-atheists. Lack of belief in the supernatural needs to be seen as a legitimate way to be a friend, a parent, a child, a relative, a neighbor, a community member, a leader, a teacher, a human.  

6. People don't want to be animals.
With education, people come to accept reality. And they accept what they cannot change. Right?

7. Evolution seems to support racism, sexism, (and atheism, intellectualism, evolutionism, vegetarianism,) and every other -ism that's wrong with humanity.  
But it doesn't. There's too much to unpack here in this small space, but this is a huge problem contributing to the aversion to evolution out there. Evolution isn't just subversive because it goes against established religious dogma. It's subversive because it, as completely misunderstood and misapplied, supports racism and sexism and murder and warfare and rape and infanticide, etc etc etc... Understood well, or even just a little bit well, evolution cannot be used in those ways and then, as a result, avoided by those who are afraid to align with such an unsavory worldview. Evolution is just generation to generation change in lineages that have shared ancestors in the past. Evolution describes how everything depends on what came before. That is all. Evolution requires no differential value placed on one species over another (human exceptionalism). Evolution requires no differential value placed on one skin color over another (racism).  Evolution requires no differential value placed on one sex over another (sexism). Those are human inventions. Culture is powerful.  

8. Evolution tells me I'm going to die when I die. 

This is the human condition. Belief in the supernatural or not, acceptance of evolution or not, this is what we're all dealing with. We often lament how, "evolution reduces the meaning of life to survival and reproduction." Well, if it does, is that so bad?

**

Evolution's got a lot more than fundamental religious beliefs working against it.  As an educator, I can't help but think that, first and foremost, a clear understanding of what evolution is (and isn't) is key to addressing all of these issues contributing to evolution's P.R. problem.  Yesterday's post was my attempt to help provide that clear understanding: 

Evolution is the only natural explanation. And it's all we need.

Forget bipedalism. What about babyism?

First, a little time travel experiment...

Here's a newspaper headline and blurb from 709,987 CE: 

Hominin fossils dated to 2,012 CE show arboreality

Artists have made a realistic reconstruction (above) of an early human species based on the anatomy of the latest fossil discovery in paleo-Alabama by a team of paleontologists. These primitive hominins were still climbing trees!

source

In yet another reconstruction of this primitive species (above), an adult forages for honey by scrambling nimbly up a tall tree trunk. 

In other paleontology news, a team of scientists determined that a Morrocan variety of domestic goat, from roughly the same primitive era, could adeptly climb small bush-like trees.

**

*A-hem*

I promise that's not sarcasm or postmodernism! That's just me trying to jossle you loose of some traditional assumptions and spark you to wonder about how we know what we know about the functional relationships between anatomy and behavior.

I'm thinking about this because of the latest and greatest news in the world of paleoanthropology, published this week in Nature and here's a nice video to bring you up to speed:



If this Burtele foot fossil represents a hominin, it's different enough in anatomy (and the functional interpretation of that anatomy) to be considered something separate from other hominins on record.

It's this whole other animal.

As of now, all hominins at this time in the mid Pliocene (the foot is dated to 3.4 mya) belong to the genus Australopithecus and are only known from sites in East and South Africa. Perhaps the Burtele foot is another species that is not A. afarensis (which supports long-existing arguments that there are two lineages at this time) or maybe this is an ancestor to the Paranthropus radiation that occurs in the early Pleistocene. Or maybe it's not even a hominin, because the foot is very ape-like. Moreso than any australopiths on record.

Chimpanzee displaying it's non-human-like hallux (big toe). 

Can we tell what this animal is? Without teeth and cranial bones--our gold standard for identification and distinction--can we surmise what kind of creature this Burtele foot belonged to?

For starters, if it's to be deemed a "hominin," we should determine what exactly about this foot is human-like.

In terms of metrics, the Burtele foot shares traits with humans but these are also shared by gorillas and sometimes chimpanzees and sometimes old world monkeys too. The striking similarities between human and gorilla feet have been known since the earliest comparative anatomy studies and it was only a matter of time before a new primitive fossil brought the problem to heightened prominence.

For the qualitative traits, more similarities appear to be shared with the famous "Ardi" skeleton from about a million years earlier in time (belonging to Ardipithecus ramidus) than with extant humans.

According to the paper, there appears to be few derived, hominin-specific features in this foot. And that's even if you are on board with calling Ardi a hominin. Granted, we expect more primitive hominins to share few of those traits with us and traits evolve mosaically, even within the foot. And granted, not all hominins contributed directly to our evolution, so we might find species on the hominin branches of the TOL that share no derived features with humans. Still, the case isn't very strong for this Burtele foot being a hominin.

One of the reported hominin-like traits has to do with the shape and orientation of the proximal phalangeal joint where it articulates with the second metatarsal head. This appears to indicate that the foot was experiencing more toe-off during walking, more like human walking than like ape walking since it's not the condition found in ape feet. This functional interpretation seems to be based on that made of Ardi's foot. Unfortuantely I don't think anyone's looked at the biomechanics of this joint in apes (and ape feet) as they walk bipedally, yet. (But I could be wrong!)

Also, although the degrees of torsion in the second metatarsal is ape-like, the torsion in the first metatarsal is more humanlike. (Torsion describes the orientation of the proximal joint surface relative to the orientation of the head. The Burtele foot's MT2 and MT4 are reported to have less torsion than that seen in African apes (where this is associated with a grasping orientation), yet are still significantly twisted compared to human metatarsals.)  The torsion in the big toe (hallucial metatarsal) is reported to be unlike that of African apes, and presumably more like humans? It's not clear. But the actual measure of the degree is not included in Table 1, nor is it demonstrated in the Supplemental section as implied. So we have to take their word for it. And by the look of the Burtele first metatarsal in the photos, that's probably not a problem.*

So there are some leads away from extant African apes and weak ones toward Ardipithecus and possibly extant humans, but what the paper demonstrates better than the hominin status of the Burtele foot is just how difficult it is to pin down hominin-ness.  We don't always know it when we see it.

For most of us and I assume the authors of the paper, this is what makes paleoanthropology so fun! But it's also why we fight.

That's not because we don't know how anatomy and behavior are linked in extant humans, apes, monkeys, etc... we seem to have a pretty good handle on that. At least big picture. The problems arise when you zoom in. Are chimpanzees really arboreal? Yes. Are they really terrestrial? YES. Same for gorillas.

So reconstructing an evolutionary scenario in which our hominin ancestors went from a state of arboreality to a state of terrestriality is not that simple. The Burtele foot describers definitely understand this. It's just the popular media that doesn't have the time or the inclination to get this. Hence my intro above.

But that intro up there with the futuristic newspaper wasn't purely reaction-against-media-reaction. It's also me reflecting on issues closer to home for paleoanthropologists.

Do primitive "arboreal" traits in hominin skeletons really correlate with arboreal behaviors? Or are they ancestral relics? We don't do much climbing anymore but we have all kinds of anatomy that links us to our tree-hugging relatives, and presumably to our shared tree-hugging ancestors.

So at what point do we recognize primitive traits as being only that? Why must all traits we observe in extinct animals be so USEFUL?

The answer is.... because that is the only way to go about these functional studies. By definition functional anatomy indicates FUNCTION. So we go in with a bias toward identifying function, NOT with an aim to identify primitive relic anatomy that just happens to work for the animal. The latter is so much harder to perceive although one might argue it's what our null hypothesis should be. It's easier to assume that if an animal has the anatomy, then it's functional and therefore it's "for" doing whatever it is that it does with that anatomy.

Who cares about these subtly different approaches to comparative anatomy and evolutionary reconstruction?

Well if you're trying to determine when bipedalism became habitual and when hominins stopped relying on trees for foraging, fleeing, socializing, and nesting, then it matters whether functional anatomy is function or whether functional anatomy is just hanging on. (pun intended) Welcome to the nightmare that is paleoanthropology!

So where does the Burtele foot leave us?
1. Looks like we've got a separate ape-y thing that's not Lucy's species (A. afarensis) living around the same time and place as Lucy and her ilk.
2. Looks like whatever this animal is it doesn't have the few derived features found in some australopith feet. (those are even debated...)

But speciation, co-habitation, and bushy hominin phylogenies aren't even the coolest part of this story.

The two distinct foot morphs offer another kind of insight.

Lemme show you.

First of all, what is arboreality and how much arboreality is enough to require specific grasping adaptations in the big toe?

We know that cercopithecines (like macaques and baboons) vary pretty widely in their degrees of arboreality and terrestriality, but regardless, they're good in the trees and they're good in the trees despite their short and diminutive big toes! Arboreal behavior can be accomplished via many different evolutionary processes revealed to us via skeletal anatomy.

Here are two baboons showing off their small big toes.

Baboons are considered to have terrestrial adaptations in their feet that are similar to those in humans like with their shorter phalanges, but they're also the opposite of humans with their short, not long big toe.  Like with arboreality, terrestriality works via many different evolutionary processes that are revealed via the skeletal anatomy...and this goes beyond primates. (The crux of it all for human evolutionary reconstructions is determining how bipedal terrestriality differs from quadrupedal terrestriality.)

Gibbons (apes) are super aboreal, but their locomotion biases grasping hands, not feet. However, their suspensory behavior does use the grasping big toes.

Here are some gibbon feet displaying their big big toes.

Here's a film showing a gibbon using its grasping big toe: http://www.arkive.org/bornean-gibbon/hylobates-muelleri/video-08a.html

Conclusion: The arboreal use of the strong grasping big toe is not necessarily about climbing or even walking on tree limbs;** it's probably more about suspension.  Suspensory behavior is typified by the gibbons, orangutans (many at least), and the rest of the apes and so is the grasping big toe. That's the strongest functional explanation for the ape's thumblike big toe.

Now, larger apes are not suspending as much with their toes. And they can get up into the trees just fine without grasping with their big toe.****

DeSilva (2008)

So think about who's doing much of the suspension particularly in African apes: Juveniles.

Suspending from vines and tree branches is one thing, but also, climbing trees with immature musculature is certainly helped by a grasping big toe.

And then of course, grasping not just trees and vines, but grasping mother is important as well.

Is there any way we can investigate this ontogeny-based hypothesis for a grasping hallux?

Let's consider the foot as a whole first, and then get back to the big toe as a grasping tool.

We can see whether foot size varies during ontogeny in different primates.

I have looked at the size of macaque (monkey), gorilla and chimpanzee (Pan) feet through ontogeny (granted, a cross-sectional sample, not a longitudinal one).***

Because macaques grow up faster than the two apes which share developmental pace, here's how I lined up the age groups (1-5; 1 = infants and 5 = adults) so that I could fairly compare growth among them.

And here are the results where I compared relative foot size during ontogeny (over age groups 1-5). Femur length was my measure for overall body size.

The box and whisker plots show you how macaques are born with big feet relative to body size, relative to adult proportions. The ontogenetic changes in proportions that they experience, over the age groups I've constructed, are significant according to the ANOVA.

By contrast, and granted I had small samples of chimp and gorilla infants ... those apes are born with adult foot size proportions which are small relative to what macaque infants are working with. Larger, more adult feet at birth contribute to macaques' relative behavioral precociality compared to young gorillas and chimpanzees who are relatively altricial. With those big feet macaques can better navigate a big world.

Chimps (and especially humans) are relatively behaviorally altricial at birth compared to macaques. Neurological development factors into this, but the small feet (in a big world) are also part of that altricial package.

Now, to bring this back around to grasping thumb-like big toes in apes!

During their longer periods of infant and juvenile dependency, gorillas and chimpanzees spend quite a bit of time clinging to mom. Big feet for body size would help cling to mother like with macaques. On a relatively small foot for body size--and in a relatively more dependent baby which is taking longer to achieve independence and is requiring more mother-infant care and bonding and learning--the thumb-like grasping big toe would come in handy (or footy).

(We've got some residual ability still...see here.)

In this scenario, the grasping hallux is an adaptation for surviving the earliest stages of life as a small footed more vulnerable, slower-developing, extensively dependent ape infant.

So what does this have to do with Pliocene hominins?

First of all, it means that morphology should be considered in an ontogenetic context so that our adaptive hypotheses and evolutionary reconstructions are as robust as possible.

And second of all, if you're basically a dedicated biped and you've got free hands to help carry your baby (rather than demand it hang on for dear life)  then selection for grasping ability in babies might be relaxed. Meaning that relaxed selection on grasping foot anatomy could have preceded any selection for all the derived features we associate with bipedalism. This isn't new territory. Most of us assume that bipedal behavior preceded the refined (as much as it can be considered refined) bipedal anatomy.

To sum up, at some point hominin infants lost the ability to cling to mother and at some point we lost our foot thumbs. These evolutionary events might be related.

What does this mean for Lucy and her kind (with their non-grasping feet) and for the Burtele foot's kind (with their foot thumbs)?

Lucy would have had to care for infants more intensely than the Burtele gang. These species would have had different mother-infant interactions.

Babyhood and motherhood...that's a whole lot more profound than straight up metatarsal anatomy.

*I was derided for not strongly-enough demonstrating claims like this in my one attempt at publishing fossil foot bone descriptions. I trust this was an oversight in moving information to the supplementary section or collateral damage due to some other editorial process. Or it's my inability to read this paper properly!
**Wunderlich (1999) measured metatarsal head pressure during walking on the ground and a pole (branch) in chimps and found that the peak pressures for MT1 were higher on the ground than on the pole. And that's not just absolutely, but relative to to the other MTs.
***Dunsworth HM. 2006. Proconsul heseloni feet from Rusinga Island, Kenya. Doctoral dissertation, Pennsylvania State University.
****Correction: should have better worded what I see as a diminished role of the grasping big toe, not the elimination of it.

"Bless the blog. Nothing else like it."

Note on the missing images: Apologies for the now dead links to once-adorable images! When I originally posted this piece, I didn't know how to best post images that could potentially disappear in the future from their source sites. 

Let’s get this straight once and for all: They’re not monkeys, they’re apes.

I’m going to try to help you understand why that jackhole at the zoo corrected you about a silly word in front of your kids last Tuesday.

Here goes.

I’ve seen it happen many times: A mother and her kids are standing at the glass pointing at the gorillas inside the exhibit (in the "ape house" with labels everywhere) and the mother says, “Look at the silly monkeys!”

On cue, a bystander interjects, “They’re not monkeys, they’re apes,” which irks the mother and she walks away.

In my brief stint so far doing observations at the Lincoln Park Zoo, I have met a ton of people as they file past Jojo's group of gorillas. Most of the interactions are positive, make what I'm doing feel even cooler than it already is, and validate the importance of the research. And I have never once corrected anyone who I (very often) overhear calling the gorillas “monkeys.”

If asked, or if I’m approached and a conversation ensues, then I do correct any number of misconceptions people may have about the gorillas (e.g. that they're monkeys or that the females are ashamed after they have sex... jeepers!), but I never impose myself on anyone visiting the apes, without their permission. This is hard to do for a professional educator, but it’s my M.O. because I think it's polite and it's not my primary concern or role there... collecting behavioral data is.

But you know what? It’s getting harder and harder to stay silent. The insanity of the whole situation is building to a nearly unbearable level. It’s beginning to blow my mind, the incredible number of people who call apes monkeys.

Mind you most of my friends know monkeys from apes, but here’s why it’s so staggering…

What if you were at the park and met a nice lady and her toddler who wanted to pet your dog and the lady told her kid that your dog was a cat?

You might think, at first, that she's not a native English speaker, but she has an American accent. Okay, then you might think that maybe she's hard of seeing, but for this example, she’s got 20/20 vision and even blind people would assume a pet on a leash was first a dog and only rarely a cat. What if you corrected her and instead of blaming it on a "senior moment," she furrowed her brow and found a way to end the interaction? What else could you possibly think about this mistaken woman except that she must be INSANE? No sane person would teach their child that a dog is a cat, would think a dog is a cat, or would never have learned during their whole life that a dog wasn't a cat.

Dogs and cats are distinct. Easy.

So are monkeys and apes. Just as easy. Confusing them, like confusing cats and dogs, is either embarrassingly lazy or is downright flirting with insanity.

Apes are gibbons, siamangs, orangutans, gorillas, chimps, and people. We apes don’t have tails and we have big brains and advanced cognitive skills among other traits. Monkeys have tails (even ones that look tailless have little stubs) and most have much smaller brains (an exception being the capuchin).

Apes and monkeys are separate categories of animals. This is why calling an ape a monkey sounds absolutely crazy and that is why some people just can’t help themselves and morph into prickish pedants around ignorant zoo visitors.

Would you call a horse a zebra? No.

Would you call a goat a sheep? No. Or if you did, the farmer would correct you.

Would you call a frog a toad? No. Well, maybe you’d do that because it's so common, but frog- and toad-ologists hate that.

And, apologies to the frog- and toad-ologists out there, but since monkeys and apes are our closest relatives, there is much more at stake when we mislabel them.

We sound so stupid* when we don't know the names of our own relatives. And these aren't even species level names... they're big broad categories of animals that small children are capable of learning.

And no! Knowledge of the animal kingdom is not child's play. It's everyone's Earth. Look around.

Granted, "monkey" is a lot more fun to say than "ape." You don't hear people going gaga over their kittens with, "You look like a little ape!"** So being so much more ubiquitous in our daily vernacular, I do understand how the word "monkey" may be more prominently tattooed on our neurons and might rest further down the tongue than the word "ape."

It's also clear that many zoo visitors are new parents who haven't yet relearned all the things they learned long ago but have since forgotten. They just need a little more time. (This is some of the joy of parenting that I look forward to one day. Differential calculus here I come, again! I've missed you.)

But, it really doesn't matter why so many humans can't bother to distinguish monkeys from apes. What matters is that for your own reputation, for your own dignity, you call apes apes and monkeys monkeys.

The gorillas don't care what you call them from behind the glass, but many of your fellow humans do, and you probably care what your fellow humans think because that's prosocial behavior.

So here's a big sorry on behalf of jerks everywhere who can't help themselves but tell you, "they're not monkeys, they're apes."

And also, on behalf of people everywhere who know that apes aren't monkeys, thank you so much for getting it straight!

*Jeepers. For me to write a word that I abhor, must mean that I mean business.

** Check out my favorite response video ever.

Images modified from: channel.nationalgeographic.com and www.ocf.berkeley.edu