
Why Turtles Evolved Shells - kjhughes
http://www.theatlantic.com/science/archive/2016/07/the-turtle-shell-first-evolved-for-digging-not-defence/491087/?single_page=true
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kjhughes
Beyond explaining the curiosity of a turtle's shell, I really liked this
article for introducing me to _exaptation_ :

    
    
       The turtle’s shell, then, is a wonderful example of exaptation
       —the evolutionary process where a trait evolves for one function
       and is then co-opted to serve another. They began as digging 
       platforms and then became suits of armor. Feathers are another 
       example. They now help birds to fly, but they probably originated 
       as ways of keeping warm or signaling to mates and rivals.

~~~
jonchang
"Exaptation" has slowly been replacing the older term "pre-adaptation", which
biologists avoid using because of its teleological implications.

~~~
paavokoya
Exaptation is a product of exaptation.. _smirks_

~~~
dredmorbius
Antiteleological principles developed in order to avoid teleological
justifications.

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emilong
It's always interesting to me when evolution is framed in terms of "why"
something happened rather than "this mutation was more suited to the
environment at the time." In this case, sounds like shells were good for
digging, now are good for protection. I suppose such headlines are well-suited
to our current popular understanding of evolution. (Also... I like turtles.)

~~~
taco_emoji
How would you reword the headline?

~~~
emilong
Excellent question! I'm not sure I could do much better, tbh. Maybe something
like, "New theory suggests turtles shells used for digging before protection."
Not nearly as succinct, to be sure, but less click-baited. The current title
certainly got me to click through...

My original comment really was one of curiosity and theophrastus's link to
Teleology above hit on exactly the thought process that I was wondering about.

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galaktor
TL;DR:

For digging.

~~~
zellyn
Came here to type this comment. Man, did they ever bury that one. I finally
went back to ctrl-f "dig", and it was in fact in the intro, but just in
passing…

~~~
ralusek
I wonder if a turtle helped bury it.

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cpsempek
And should the turtle flip while digging? Thankfully, we have the assurance of
geometry to tell us it will get back to digging in no time.

[http://rspb.royalsocietypublishing.org/content/275/1630/11](http://rspb.royalsocietypublishing.org/content/275/1630/11)

~~~
mangodrunk
Similar to a gömböc:
[https://en.wikipedia.org/wiki/G%C3%B6mb%C3%B6c](https://en.wikipedia.org/wiki/G%C3%B6mb%C3%B6c)

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dredmorbius
Another concept that's useful in this context is that of _the adjacent
possible_. Rather than get bogged down in concepts of teleology, realise that
_for an adaptation to occur, it must be beneficial_ , or, at the very least,
_not disadvantageous_.

So, from proto-turtle to current evolved state, the shell had to pass through
various forms which were _adjacent_ and _possible_ to their progenitor state,
_and_ subsequent state.

While the end result wasn't a _goal_ , it had to exist _on the possibility
path which lead to it_. That is, adaptations are _path dependent_.

Which applies as well to technological and enterprise progress. For a company
to evolve from some precursor state A to some ultimate state C, it's got to
pass through some intermediate set of possiblities, B, B', B", etc.
Maintaining corporate solvency, existence, some employee retention, etc., are
all necessary. And original intent often _isn 't_ the final result.

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SocksCanClose
I wish we talked about evolution a bit differently. It's not that "turtles"
"evolved" shells. It's that as the population of turtles mutated into various
forms, certain ones survived and thrived, and others didn't.

~~~
pje
It's almost as if someone decided to give that phrase a name, and decided to
use the word "evolution".

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Pica_soO
It was the only way to escape being used by all other species as drawing tools

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danvoell
How Titles Evolved: It Wasn't for Giving Away the Actual Information in the
Article

~~~
Fiahil
Five Things You Won't Believe BuzzFeed Has Done To This Industry.

~~~
ralusek
One thing you wouldn't believe has existed since far before BuzzFeed.

~~~
dredmorbius
When a headline exists, on a page, to catch your eye and lead you _in a few
thousandths of a second_ to the story, vs. online, where fully loading a
weaponised viral clickbait story can take 10-20 seconds, to a minute or more,
is a huge difference.

I prefer offering 1) descriptive titles and 2) informative microcontent, as
Jacob Nielson has been advocating for nearly 20 years now.

[https://www.nngroup.com/articles/microcontent-how-to-
write-h...](https://www.nngroup.com/articles/microcontent-how-to-write-
headlines-page-titles-and-subject-lines/) (1998)

[https://www.nngroup.com/articles/pogo-
sticking/](https://www.nngroup.com/articles/pogo-sticking/) (2015)

[https://www.nngroup.com/articles/does-user-annoyance-
matter/](https://www.nngroup.com/articles/does-user-annoyance-matter/) (2007)

[https://www.nngroup.com/articles/link-
promise/](https://www.nngroup.com/articles/link-promise/) (2014)

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harveywi
Turtles evolved shells so that they could work from home.

