
Scientists find remains of huge ancient herbivore - dnetesn
https://phys.org/news/2018-11-scientists-huge-ancient-herbivore.html
======
calibas
It's barely been a week since the existence of a whole new kingdom of life was
confirmed
([https://www.nature.com/articles/s41586-018-0708-8](https://www.nature.com/articles/s41586-018-0708-8)),
certainly an exciting time for biologists. Must be tough even keeping up with
the latest developments.

~~~
lake99
If we're talking about single-celled organisms, it's quite possible that there
are hundreds of "kingdoms" living among us. The trend to abandon the Linnaean
classificaton is quite prominent among those analyzing macroscopic organisms.
But among those working with microscopic organisms, I've come across some of
them abandoning the tree of life itself. My mind was blown when I watched the
discussion between Dawkins and Venter.

[https://en.wikipedia.org/wiki/Kingdom_(biology)#Summary](https://en.wikipedia.org/wiki/Kingdom_\(biology\)#Summary)

[https://evolutionnews.org/2011/03/venter_vs_dawkins_on_the_t...](https://evolutionnews.org/2011/03/venter_vs_dawkins_on_the_tree_/)

~~~
gus_massa
The last article is extremely misleading. It is true that there are variations
of the genetic code. (Wikipedia says 32, including the usual genetic code that
we have.
[https://en.wikipedia.org/wiki/List_of_genetic_codes](https://en.wikipedia.org/wiki/List_of_genetic_codes)
)

But the variations are minor, each has only a few changes from the most used
code. For example mitochondria (that are also "we") have only 4 changes out of
64
[https://en.wikipedia.org/wiki/Vertebrate_mitochondrial_code](https://en.wikipedia.org/wiki/Vertebrate_mitochondrial_code)
.

So the easiest explanation is that the genetic code evolved from a genetic
code ancestor. Moreover, our genetic code is probably not the original code.
IIRC the guess is that initially it has only 16 slots. These slots are visible
as some big squares in the curren table, but some of these slots are divided
now.

Most of the time a change in the genetic code is catastrophic, so it's not
easy to change it. But it may be possible if it changes one aminoacidic by a
similar one, or if you are extremely lucky. In the table all the changes are
in mitochondria/bacteria/archaea, not in animals or plants. Since they are
small, they have bigger numbers and faster generations, so they have a bigger
chance of a lucky random mutation.

In particular, 12 of the 32 genetic codes in the list are variations in
mitochondrial code. All the mitocondria are very similar. The incorporation of
mitocondrial was a very strange lucky event. Nobody think that the 12 variants
of mitochondria appear independently, each one in its own tree of life, and
were absorbed later independently.

~~~
lake99
I don't like the "gotcha, Dawkins" stance of the article, but apart from that,
it looks like they were doing their best to fill in the gaps that Venter left.
If memory serves me right, this discussion panel met shortly after Venter's
group announced the creation of a life form with a completely synthetic
genome. Venter had adequately proven his credentials by that point, and so the
panel deferred to his expertise.

Given that the likes of Dawkins could not follow along, Venter certainly did a
poor job of communicating the ideas.

------
burtonator
I was hoping this was from the pleistocene... for some reason I'm fascinated
that animals like the Giant Sloth existed only 15k years ago.

~~~
craftyguy
One species of Mammoth existed until about 2.4k years ago[0].

0\.
[https://journals.uair.arizona.edu/index.php/radiocarbon/arti...](https://journals.uair.arizona.edu/index.php/radiocarbon/article/view/2015)

~~~
richardknop
Is it known what killed off mammoths? Was it human hunters killing them of or
some natural cause? Something like climate change that caused them to not have
enough food?

~~~
dotancohen
Consider that mammoth populations survived past the ice age in places that
humans did not live, mostly islands north of Siberia. Now consider that those
mammoths were quickly extinguished as soon as humans touched foot on those
islands.

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alejohausner
This was a giant _mammal_ that coexisted with dinosaurs. I had always thought
that mammals appeared during the age of dinosaurs, but they were all tiny
mouse-sized mammals.

~~~
Arnt
The ones that survived the Giant Frying were mouse-sized, but bigger ones
existed before then, even though they might look mouse-sized to a passing
brontosaurus.

(On the Giant Frying:
[http://uahost.uantwerpen.be/funmorph/raoul/macroevolutie/rob...](http://uahost.uantwerpen.be/funmorph/raoul/macroevolutie/robertson2004.pdf)
)

~~~
nerdponx
There's nothing quite like a well-written scientific paper. This isn't my
field at all but I enjoyed reading this immensely.

------
mcguire
Looks like a giant guinea pig.

Nature never ceases to amaze me.

