musingsonwomenshealth.com

Reflections on 40 years as a doctor in Women's Health

Give every thing thine ear


I admit that there are some things I don’t think about very much anymore: my ears, for example. I mean until I had to get hearing aids and needed to find a place to put them where they wouldn’t come off along with my hat, or snag on my hair as I walked around, I was blissfully unaware of my ears.

Of course, when I was young I suppose I went through the usual ‘do I fit in?’ stage. I remember thinking that my nose was too large, and I was sure that the braces on my teeth glinted too brightly if I smiled in sunlight. I kept checking my breath by smelling the palm of my hand after I exhaled into it to make sure that wasn’t why girls always seemed to wrinkle their noses and look the other way when they passed me in the school corridor.

Then there was the phase when I figured I was too short compared with the other guys. And I hesitate to get into the sure and certain suspicion that my awkwardness was all due to the bright butterscotch frames for my heavy thick glasses that always seemed to slide down my nose when I walked. My mother had insisted I wear them so I could see the chalkboard at the front of the classroom; I don’t think I had much time to wonder about my ears in those days…

I mean ears? Let’s face it (sorry), if they don’t stick out past your hat, or hang down like shopping bags, they’re just there, eh? Of course, we sometimes want to show them off as we do with other external protuberances like the fingers or toes of which we’re proud, I suppose. Still, I’ve never had anything there which I wanted to showcase -especially now that I am adorned with gnarled fingers and toenails popular with fungal runaways.

And I don’t wear earrings or anything either, although there was a time when, unwilling to get a piercing but still wanting to appear trendy, I bought a silver slip-on ear-cuff to wear on one of them. Unfortunately, for its debut appearance I apparently chose the wrong ear to put it on and lost all bragging rights. Still, live and learn…

Anyway, back to the why and where of ears. In the naïveté of youth, I expended little thought on whether all animals had external ears. I figured birds just covered them with feathers, and crocodiles with scales -the same with fish, although for some reason, that class of the Linnaean taxonomy managed to escape my curiosity… Well, on really inquisitive days, I suppose I simply assumed fish ears were tucked away somewhere to reduce the drag in water. Come on, I was just a kid, eh?

Later in my life, though, I became aware of the role fish played in hearing: ‘the genes responsible for mammals’ external ears might have arisen from those that produce fish gills. It builds on previous research that suggests the jaw bones of ancient fish evolved into the three inner ear bones that mammals have today.’[i] Okay I already knew that, but I didn’t link external ears with fish gills… Still, there are ‘similar gene activity patterns and DNA sequences in the gill tissue of zebrafish and the ear cartilage of humans.’[ii] You have to be retired to have the time to read that kind of stuff of course.

Actually, for interested scientists to be able to figure that out was rather clever, don’t you think? It’s called an exaptation -a lazy way to use something you already have but in a different way and for a different purpose. It saves you from having to figure out how to build something new when you’ve already got parts for it in the garage which you could adapt.

I mean it goes on all the time without the need for animals, say, to have to think about it. Elephant ears, for example. No animal in its right mind would choose to drag around beach-blanket ears pinned to their heads in the heat. They (both the animals and their ears) live in hot climates and have allowed themselves to get to ridiculously enormous sizes, so unless they could migrate to somewhere cool, or live their lives like hippopotami, almost submerged in water, we’d probably only know about elephants (not their ears, I don’t think) from fossils.

But ears came to their rescue and because of their duvet size, enabled them to act as heat dissipaters to help the huge bodies to which they were attached to regulate body temperature. They probably catch more branches than sound, but hey, when you’re that big most other things keep quiet anyway, I figure.

At any rate, the more I think about my ears, the more I appreciate Goldilocks’ choice of baby bear’s porridge: we ended up with the ‘just right’ ones. I mean the ear  lineage goes back to the gills of horseshoe crabs, invertebrates that have changed very little over the last 400 million years, and the first fish in turn repurposed the gill-forming genes from those ancient creatures. I’m merely keeping the tradition alive and flaunting the result: credit given where credit due.

In fact, come to think of it, I believe I know where that old ear cuff is. And even if I wear my hair longer nowadays, I’m going to use the other ear this time. I’m a little worried about snagging my hearing aid, though…

[i] https://www.smithsonianmag.com/smart-news/why-do-mammals-have-outer-ears-scientists-are-getting-closer-to-solving-the-mystery-180985884/?

[ii] Ibid.

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gozzter

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