
558M-year-old fossils identified as oldest known animal - Hooke
https://www.theguardian.com/science/2018/sep/20/558m-year-old-fossils-identified-as-oldest-known-animal
======
stareatgoats
The article states that the fossil was "an animal", without further explaining
what actually constitutes "an animal", or what characteristics made it unique
compared to other organisms at the time (or now for that matter). Maybe it's
evident to people in the field, to a layman (like me) the term 'animal' is
fairly fuzzy.

I went to Wikipedia and found this definition: "With few exceptions, animals
consume organic material, breathe oxygen, are able to move, reproduce
sexually, and grow from a hollow sphere of cells, the blastula, during
embryonic development".

So these 'Ediacarans' fall into this category?

~~~
ajross
They mean "an animal" in the cladographic sense as being part of the same
evolutionary tree as modern animals, and not e.g. lichens or funguses.
Specifically, they seem to have detected cholesterol (or some decay product
thereof maybe) in the fossil, which is a lipid that only animals make.

The identity of the ediacaran fauna has long been controversial. They don't
"look like" modern animals (all of whom descend from forms that appeared
later, in the cambrian explosion), so they're hard to place. This is a big,
big result if it holds up.

FWIW: this is the Wikipedia article you want to be reading:
[https://en.wikipedia.org/wiki/Ediacaran_biota](https://en.wikipedia.org/wiki/Ediacaran_biota)

------
fifnir
The paper:
[http://science.sciencemag.org/content/361/6408/1246](http://science.sciencemag.org/content/361/6408/1246)

Here's a bit more on what they did:

>We applied a new approach (17) to test the lichen, protist, and animal
hypotheses by studying biomarkers extracted from organically preserved
dickinsoniids. Hydrocarbon biomarkers are the molecular fossils of lipids and
other biological compounds. Encased in sedimentary rock, biomarkers may retain
information about their biological origins for hundreds of millions of years.
For instance, hopanes are the hydrocarbon remains of bacterial hopanepolyols,
whereas saturated steranes and aromatic steroids are diagenetic products of
eukaryotic sterols. The most common sterols of Eukarya possess a cholesteroid,
ergosteroid, or stigmasteroid skeleton with 27, 28, or 29 carbon atoms,
respectively. These C27 to C29 sterols, distinguished by the alkylation
pattern at position C-24 in the sterol side chain, function as membrane
modifiers and are widely distributed across extant Eukarya, but their relative
abundances can give clues about the source organisms (24).

------
HarryHirsch
It's remarkable that the components of the nerve system are very ancient and
were all in place in the ur-bilaterian.

~~~
mentos
It’s crazy how life just kept building and building on itself. I feel like
there were so many opportunities for life to hit a ceiling and never evolve
past X stage but yet somehow we broke out.

~~~
mcguire
If I recall correctly, the division between prokaryotes and eukaryotes took
billions of years. Multicellular life was another big step.

Everything after that is easy. I remind myself that every morning. :-)

~~~
Emma_Goldman
I've heard this said many times and believed it, but read to day that the leap
from single-cell to multi-cellular organisms happened a dozen or so times
independent of each other. That makes it an order of magnitude less
improbable, if true.

~~~
gus_massa
Yep, from
[https://en.wikipedia.org/wiki/Multicellular_organism#Occurre...](https://en.wikipedia.org/wiki/Multicellular_organism#Occurrence)

> [...] _However, complex multicellular organisms evolved only in six
> eukaryotic groups: animals, fungi, brown algae, red algae, green algae, and
> land plants. It evolved repeatedly for Chloroplastida (green algae and land
> plants), once or twice for animals, once for brown algae, three times in the
> fungi (chytrids, ascomycetes and basidiomycetes) and perhaps several times
> for slime molds and red algae._

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throwaway2048
Does anyone have any details about how they know the bio markers were the
result of cholesterol?

~~~
brennebeck
Up above there’s a link to the paper:
[https://news.ycombinator.com/item?id=18050904](https://news.ycombinator.com/item?id=18050904)

------
solarengineer
When I read such news, I wonder how people reconcile such discoveries backed
by scientific validation, with religious texts that provide other timelines
and explanations.

~~~
zw123456
I can give one example explanation. My Father is an evangelical Christian
(FYI, I am not, I am an atheist and a science enthusiast). I have asked him
this exact same question out of curiosity. Here is the answer he gave (albeit
just one perspective). He said "God is so powerful that he can do anything
including placing all that evidence there to test our faith". That shuts down
any reason to continue a conversation (needless to say this is a topic we
generally avoid).

Someone once said (not sure the attribution) "never try to reason with someone
who has irrational beliefs".

~~~
lisper
Your father's beliefs are not necessarily irrational, they are just based on
different assumptions. Your assumption is that the order in the universe
arises from causality and physical law. His assumption is that the order in
the universe arises from purpose, i.e. he believes in teleology. That is not
in and of itself irrational.

~~~
carapace
I disagree, the belief system as described is strictly irrational, in the
sense that its fundamental assumptions contain a inconsistency that then
permits one to prove anything. (I.e. A = not A therefore anything.)

It's a case of a mind trained into a kind of _cul-de-sac_ with no way out. For
some people this keeps them on the straight and narrow, for others it runs
them smack into a wall. But it is certainly _irrational_ to believe in a
Divine Omnipotent Creator who plays crude tricks on you.

~~~
lisper
> its fundamental assumptions contain a inconsistency

Really? What is it?

~~~
carapace
Well, rumcajz points out Bertrand Russell's objection, and apocalypstyx
presents a fascinating aspect of the matter too, but the problem I'm talking
about is the nature of implication/causation itself.

Rationality rests on implication.[1] The system we're talking about literally
has "GOD -> anything" as an axiom, so it's useless for reasoning. If GOD -> (A
-> B) for all A, B, and "->" then you can literally "prove" that anything
implies anything else, or that _everything_ implies God, but you can't
_disprove_ anything at all. Saying that there's a part of the system that can
change anything about the system is essentially saying that there's no system
at all. "Black is white and you get run over at the next zebra crossing."

If you believe that God will play tricks on you then you have nothing external
to rely on. Again, this can be good or bad for a given person depending on
their context. It's useless for reasoning, but you don't actually have to e.g.
believe in Dinosaurs to reach God, so in that sense having no ability to
rationalize can be a benefit if it prevents spiritual doubts. But many people
instead are simply trapped in impoverished world-models. To wit: the Universe
as revealed by scientific investigation redounds to the Glory of God _far
more_ than, say, the concepts of "young-earthers", or people who believe God a
trickster.

[1] This is actually the one article of _faith_ at the foundation of reason
and rationality: that the Universe is comprehensible in terms of causation.
The OP's father's god-image is jealous of even this wane and paltry rival.

~~~
lisper
> The system we're talking about literally has "GOD -> anything" as an axiom

No, the system we're talking about has _purpose_ as an axiom and God as a
(perfectly rational) conclusion.

~~~
carapace
> the system we're talking about has _purpose_ as an axiom and God as a
> (perfectly rational) conclusion.

I'm sorry, but I don't see that.

The quote was:

> "God is so powerful that he can do anything including placing all that
> evidence there to test our faith"

To me, that reads as "God, therefore anything". Specifically _all evidence_ of
X is evidence of God, even (and especially) if X contradicts God.

I don't see that it says, "Purpose, therefore God."

For what it's worth, responding to a sidereal comment of yours, I agree with
you that "teleology, i.e. the assumption that existence has purpose, is not
irrational".

~~~
lisper
> I don't see that it says, "Purpose, therefore God."

It doesn't. I'm extrapolating. I'm saying that it is _possible_ that such a
conclusion can be arrived at rationally, for example, but starting from
teleology as an assumption. Because this is possible, you cannot rationally
conclude that a person is irrational just because they believe in God. They
_might_ be irrational, but they might not. To settle the question you'd need
additional data.

~~~
carapace
> it is possible that such a conclusion [God exists] can be arrived at
> rationally ... starting from teleology [purposeful Universe] as an
> assumption.

I agree and indeed I did something like that: I built a model of God based on
the assumptions that feedback exists and time is eventually transcended by
humans or other sentients through technology or other means. I eventually
discarded that model, but it was arrived at rationally.

> Because this is possible, you cannot rationally conclude that a person is
> irrational just because they believe in God.

I agree[1], however, I didn't do that. OP's father isn't irrational because he
believes in God, he is irrational because he thinks God makes fake fossils.
It's a concept of God so foolish as to disprove itself. If it were possible to
mock God this would surely be the way to do it. The Flying Spaghetti Monster
has more dignity.

[1] I am rational _and_ I believe in God, so it would be hypocritical of me to
claim that a person is irrational just because they believe in God.

~~~
lisper
> he is irrational because he thinks God makes fake fossils

You can't know that without knowing how he arrived at that conclusion. You
cannot judge the rationality or irrationality of conclusion simply by looking
at the conclusion. When you do so, you are making the exact same mistake that
atheists make when they look at you and decide that you must be irrational
simply because you believe in Satya Sai Baba.

~~~
carapace
Sorry, I was using that as a kind of short-hand and obscured my meaning. That
particular belief is a symptom of the underlying irrationality of his belief-
structure but not in itself necessarily arrived at irrationally in the general
case, eh?

> You can't know that without knowing how he arrived at that conclusion.

In this case we _do_ know how he arrived at that conclusion and we know that
it was due to a form of reasoning that obviates itself, that his reasoning is
irrational, that he is, in fact, _not_ reasoning by his own admission.

I can't say whether or not this religion is working for OP's father, but I can
(and do) say that it is irrational, because it is irrational in its structure.
Anyway, he doesn't have to reason correctly because (his) God(-image) does not
require it, He is content with irrational faith.

