
Fossilised 429-million-year-old eye mirrors modern insect vision - bookofjoe
https://phys.org/news/2020-08-million-year-old-eye-view-trilobite-life.html
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joshuahedlund
Something I've been thinking about, after seeing enough "older than we
thought" pieces, is how our incomplete fossil record has an inherent asymmetry
in it - new discoveries can never give us a later date for when something
appeared, but they can give us an older date, so our "present" understanding
of the past has an inherent bias towards assigning too late of dates for
things. I don't know what implications this has for the nuances of our
understanding of the history of our planet (I'm sure scientists are aware of
this and generally take this into account), but it's kind of intriguing.

~~~
sandworm101
>> new discoveries can never give us a later date for when something appeared,
but they can give us an older date

But neither are useful. The fact that a structure appeared at time X is not an
indication that it continued until time Y. Evolution is not linear at smaller
scales. Structures evolve/appear only to disappear through the same processes
that created them. The fact that this critter had a particular shape of eye is
not an indication that it passed that structure to later lifeforms. It is
certainly possible, but the concept that something happened "first" is
irrelevant in a world where near-identical structures regularly evolve
independently.

~~~
cossatot
> But neither are useful.

Useful to whom? To the paleontologists?

In practice, paleontologists look at the passage of traits down evolutionary
lineages regularly. You are correct in stating that the same features can
develop independently, but that does not mean they do every time. I don't
think the assertion that 'evolution is not linear at smaller scales' holds up
to much scrutiny. Life as we know it results from the passage of traits
encoded in genes, otherwise there would be no evolution; we would have basic
unicellular life spontaneously arising from the primordial ooze over and over
again Groundhog Day style.

> The fact that this critter had a particular shape of eye is not an
> indication that it passed that structure to later lifeforms.

In the parlance of the geosciences, depending on the context, we'd call this a
_suggestion_ rather than an _indication_ , as there may be weaker evidence or
credible alternative hypotheses. However depending on the scales of the time
and speciation differences between the species under consideration it may be
very strong evidence.

For example, it's highly unlikely that the presence of limbs in both _Homo
erectus_ and _Homo sapiens_ is coincidental and _Homo sapiens_ have limbs that
evolved independently of _Homo sapiens_. This is very different than asserting
that wings in both bats and birds are indications that one evolved from the
other.

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bookofjoe
>Insights into a 429-million-year-old compound eye

[https://www.nature.com/articles/s41598-020-69219-0](https://www.nature.com/articles/s41598-020-69219-0)

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Aardwolf
That's some very successful long lasting 'technology', imagine an app lasting
429 million years

~~~
noarchy
I guess we can see that there is no planned obfuscation of eye "tech".

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EamonnMR
Compound eyes may be even more basal than that:

[https://www.discovermagazine.com/the-sciences/the-sharp-
eyes...](https://www.discovermagazine.com/the-sciences/the-sharp-eyes-of-
anomalocaris-a-top-predator-that-lived-half-a-billion-years-ago)

~~~
bookofjoe
The close-up picture of the Blue-spotted-hawker-dragon's nearly 360°-vision-
capable eyes is magnificent.

~~~
eternalban
It really is. Looks like the product of a very advanced high technology
culture.

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AtomicOrbital
compound eyes consist of thousands of ommatidia which are the individual eye
component ... these animals determine direction of movement of their prey in
the layer of neurons directly attached to each of these ommatidia ... each
ommatidia has 6 immediate neighbor ommatidia ... leaving a given ommatidia are
6 optic neurons connecting that ommatidia with each of its neighbor ommatidia
... when a prey moves across the field of view directly in front of a given
ommatidia a signal spike is transmitted in all directions outward through
these 6 outgoing optic neurons ... interesting aspect is these neurons incur
an intentional time delay in this spike signal ... when the time it takes a
prey to move from being in front a given ommatidia to being in front of a
neighbor ommatidia matches this optic neuron time delay the neighbor ommatidia
senses this as a doubly large spike signal ... this gives the animal
information as to the direction of prey movement across its visual field ...
this optical computation directly is this simple layer of neurons gives the
compound eye animal extremely fast response time when hunting down a moving
prey ... think of watching a dragon fly chase down a flying mosquito

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JoeAltmaier
Ok I see the "fly's eye" texture. But it's a leap to suggest this means, the
eye was built the same as a modern insect. It could have been made of external
light-sensitive cells instead of internal; it could have been a pressure
sensor; it could even have been a touch sensor!

I'd want a lot more evidence over millions of years, showing continuous use of
this structure in sea creatures that lead to the modern insect form.
Otherwise, just another 'his-story'?

~~~
sradman
I don't think your skepticism is warranted. EamonnMR provides a link to an
article describing the paper _Acute vision in the giant Cambrian predator
Anomalocaris and the origin of compound eyes_ [1]. This animal was a pre-
cursor to modern crustaceans like shrimp and crabs. The compound lens in this
fossil has about 16K lenses.

Today's OP describes the paper _Insights into a 429-million-year-old compound
eye_ [2] in a trilobite fossil with about 200 lenses.

Logically, I can't imagine how free-swimming predators could have evolved in
the Cambrian without eyes. Having two very distinct species of arthropods with
fossilized compound eyes is not "his-story" but key evidence that furthers our
understanding of the _Evolution of the Eye_ [3].

[1]
[https://www.nature.com/articles/nature10689](https://www.nature.com/articles/nature10689)

[2]
[https://www.nature.com/articles/s41598-020-69219-0](https://www.nature.com/articles/s41598-020-69219-0)

[3]
[https://en.wikipedia.org/wiki/Evolution_of_the_eye](https://en.wikipedia.org/wiki/Evolution_of_the_eye)

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locustsandhoney
Trilobite's are said to have the most incredible optical system of any
organism, living or dead.

[https://answersingenesis.org/extinct-animals/trilobite-
eyes-...](https://answersingenesis.org/extinct-animals/trilobite-eyes-
ultimate-optics/)

