

Ancient Fossils Suggest Complex Life Evolved on Land - digital55
https://www.simonsfoundation.org/quanta/20140424-early-life-in-death-valley/

======
transfire
I think the fact that all life as we know it is essentially a "bag of water"
is pretty conclusive evidence of its origination in water. However, at some
point life clearly flirted with the land, so to speak, and thus there would
inevitably be an evolutionary track of going back and forth as organisms
become more able to go without sources of water for longer and longer periods.
The evolution of amphibians follows the same pattern. So I think it is
erroneous and sensationalist to say "fossil evidence suggests complex life
evolved on land". It would be more accurate to say something like "early life
may have evolved on land more than scientists had previously realized".

~~~
ekianjo
> "fossil evidence suggests complex life evolved on land"

Yeah, and it's survival bias as well, because by definition you don't get much
fossils in water. And by far there's way more diversity of life in water so
that would suggest clearly otherwise than what the title suggests.

~~~
dredmorbius
_you don 't get much fossils in water_

Quite the contrary. Much of the early fossil record consists of remains from
shallow seabeds where you had both 1) ample life and 2) persistent
sedimentation which would bury and fossilize remains.

Those seabeds frequently ended up on land, and not infrequently on mountains,
a fact which itself had a strong influence on modern understandings of global
biological and geological history.

The article (which you clearly didn't read) actually makes that point
explicitly:

 _Marine fossils are protected by layers of marine sediment and the quietude
of ocean deeps. Land fossils are much more likely to have been pulverized by
changing climates and erosion long before paleontologists could have chanced
upon them. The fossil record, therefore, is heavily weighted toward the seas,
making it appear that they were the cradle of life._

------
dTal
>According to prevailing wisdom, the continents were lifeless, irradiated rock
shelves until after the occurrence known as the Cambrian explosion in the seas
540 million years ago, when the precursors to rooting plants and animals burst
forth from the ocean to colonize the land.

>Taken together, the geochemical and microfossil findings support his theory
that during the Precambrian eon, complex life forms evolved not only in the
oceans, but also on land.

I'm confused. "Cambrian explosion" refers to the development of multicellular
organisms, and the resulting geologically-instantaneous biodiversity, not the
colonisation of land. Surely the leap to multicellular is a rare event that
only happened once. This article seems to be trying to imply that the ocean
was not "the cradle of life" in that sense, or that it evolved twice.

~~~
dredmorbius
Prevailing wisdom is that plant life emerged on land _after_ the Cambrian
explosion, around 542 million years ago (mya). Land plants emerged about 475
mya.

That would be "after the Cambrian explosion". Consistent with the wording
you're confused over.

[http://en.wikipedia.org/wiki/Timeline_of_evolutionary_histor...](http://en.wikipedia.org/wiki/Timeline_of_evolutionary_history_of_life)

------
leke
In the Cosmos series, it seemed to say people came from the sea because of our
eye evolution.

~~~
rthomas6
Life != humans. The early land fossils they say they've found were
photosynthesizing single-celled organisms, which seem unlikely to have evolved
into humans.

Also, Cosmos seems more interested in creating an engaging narrative for
people with little to no science knowledge than delivering an accurate and
complete model that best explains what we currently observe in the world.
That's not a bad thing, but I'd take the details they provide as a good basic
explanation but not always technically correct. For instance it bothered me
when they showed discrete electrons orbiting nuclei. Electrons don't orbit,
they exist in a locational probability around the atom in often surprisingly
shaped clouds, that is, until observed. But I don't expect a show that's
supposed to get people excited about our universe to explain convoluted
tangential details that they don't need for the overall point.

------
contingencies
Very interesting to me as I live right next to the
[https://en.wikipedia.org/wiki/Maotianshan_Shales](https://en.wikipedia.org/wiki/Maotianshan_Shales)
which are one of the major sites held to support the alternate, ocean theory.

The philosophy of the researcher is admirable, too: _In my old age, I am so
disappointed that people close their minds and jump on whatever splashy,
simplistic bandwagon is in vogue._ Perhaps the tech community can learn
something from such thinking!

------
briantakita
“In my old age, I am so disappointed that people close their minds and jump on
whatever splashy, simplistic bandwagon is in vogue,”

“But if you start with the rocks and work upward to an interpretation, it
often reveals a reality that is not the one in vogue.”

Kudos to Knauth for having the fortitude to cut through the cultural bias &
naysayers in the pursuit of truth.

