Plants colonized the Earth 100 million years earlier than previously thought

February 19, 2018, University of Bristol
Early life on land resembled cryptogamic ground covers like this lava field in Iceland. Co-author Sylvia Pressel appears in the right of the picture. Credit: Paul Kenrick

For the first four billion years of Earth's history, our planet's continents would have been devoid of all life except microbes.

All of this changed with the origin of from their pond scum relatives, greening the continents and creating habitats that animals would later invade.

The timing of this episode has previously relied on the oldest fossil plants which are about 420 million years old.

New research, published today in the journal Proceedings of the National Academy of Sciences, indicates that these events actually occurred a hundred million years earlier, changing perceptions of the evolution of the Earth's biosphere.

Plants are major contributors to the chemical weathering of continental rocks, a key process in the carbon cycle that regulates Earth's atmosphere and climate over millions of years.

The team used 'molecular clock' methodology, which combined evidence on the genetic differences between living species and fossil constraints on the age of their shared ancestors, to establish an evolutionary timescale that sees through the gaps in the fossil record.

Dr Jennifer Morris, from the University of Bristol's School of Earth Sciences and co-lead author on the study, explained: "The global spread of plants and their adaptations to life on land, led to an increase in continental weathering rates that ultimately resulted in a dramatic decrease the levels of the 'greenhouse gas' carbon dioxide in the atmosphere and global cooling.

Rhynia gwynne-vaughanii -- 400 million-year-old fossil plant stem from Aberdeenshire, Scotland. Credit: The Natural History Museum, London.

"Previous attempts to model these changes in the atmosphere have accepted the plant fossil record at face value - our research shows that these fossil ages underestimate the origins of land plants, and so these models need to be revised."

Co-lead author Mark Puttick described the team's approach to produce the timescale. He said: "The fossil record is too sparse and incomplete to be a reliable guide to date the origin of land plants. Instead of relying on the alone, we used a 'molecular clock' approach to compare differences in the make-up of genes of living species - these relative were then converted into ages by using the fossil ages as a loose framework.

"Our results show the ancestor of land plants was alive in the middle Cambrian Period, which was similar to the age for the first known terrestrial animals."

One difficulty in the study is that the relationships between the earliest land plants are not known. Therefore the team, which also includes members from Cardiff University and the Natural History Museum, London, explored if different relationships changed the estimated origin time for land plants.

Cooksonia pertoni collected by co-author Dianne Edwards from the type locality (Pridoli). It is about 12mm high. It was first published in Palaeontology Vol 22 Edwards 1979 plate 4 fig13. It is now housed in the National Museum, Wales. Credit: Diane Edwards

Leaders of the overall study, Professor Philip Donoghue and Harald Schneider added: "We used different assumptions on the relationships between land plants and found this did not impact the age of the earliest land .

"Any future attempts to model atmospheric changes in deep-time must incorporate the full range of uncertainties we have used here."

Explore further: Plants are given a new family tree

More information: Jennifer L. Morris el al., "The timescale of early land plant evolution," PNAS (2018). www.pnas.org/cgi/doi/10.1073/pnas.1719588115

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rrwillsj
1.7 / 5 (10) Feb 19, 2018
Oh yeah, the scientists were off by a few percent of timespan. Therefore total fail!

Thereuponfore, proof positive the Earth and all life upon it was created only six thousand years ago. Or, something sortof like that or not perhaps, maybe. Gotta a book somewhere around here that defiantly confirms my suspicion of them jew scientists.
Bart_A
1 / 5 (8) Feb 19, 2018
RR, no, you should look at it more scientifically.

The article's statement of "look at ancestors, to establish an evolutionary timescale that sees through the gaps in the fossil record." is a complete understatement.

The "gaps" are actually 99%+ of the fossil record. We only see specific species in the fossil record, and virtually none of anything that would help to fill in these gaps.

The article confirms "One difficulty in the study is that the relationships between the earliest land plants are not known."

And it will never be known. Because this theory of evolution is just that---a theory. It is not backed up by science.

jonesdave
4.3 / 5 (11) Feb 19, 2018
Because this theory of evolution is just that---a theory. It is not backed up by science.


Which just goes to show the ignorance of some religious types. Never studied science, so don't understand the use of the word 'theory' in a scientific context. A theory, scientifically speaking, is as close to being confirmed as you can get. 'Hypothesis' is more in line with the layman's use and understanding of the word 'theory'. So, Einsteins theory of relativity, or the theory of plate tectonics are as proven as you can get. We might not be 100% sure of every last detail, but the meat of the theory is beyond question, scientifically. Fail.
AllStBob
5 / 5 (2) Feb 20, 2018
How can the "gaps" be "actually 99%+ of the fossil record". By definition if they are gaps they are not in the fossil record. If you have such a poor understanding of English how can we take you seriously when you talk about science?
TheGhostofOtto1923
5 / 5 (1) Feb 20, 2018
The "gaps" are actually 99%+ of the fossil record
The fossil record indicates the sheer number of extinct species that have roamed the planet over time.

If all those species had existed together in viable reproductive populations at the time of the flood, the world would have been covered by a continuous pile of writhing animal flesh.

Which would have left no room for all the extinct plant species, which would have needed a whole separate planet to live on.

Barts gap is between his ears.
humy
1 / 5 (2) Feb 20, 2018
From the link;

"The fossil record is too sparse and incomplete to be a reliable guide to date the origin of land plants. Instead of relying on the fossil record alone, we used a 'molecular clock' ..."

Stop right there!
The molecular clock method for dating (see https://en.wikipe...ar_clock ).
is no where near as accurate as radiometric dating.
Thus the fossil record 'alone' SHOULD be what is used for dating i.e. WITHOUT using the molecular clock method else the estimate will be made LESS accurate from it, NOT more!

Thus it is NOT true that they discovered "Plants colonized the Earth 100 million years earlier than previously thought".
They have recovered NOTHING;
FALSE CLAIM!
FOUL!

humy
1 / 5 (2) Feb 20, 2018
From the link;

"The timing of this episode has previously relied on the oldest fossil plants which are about 420 million years old."

-yes, and for good reason! If the oldest fossil plants (on land) are about 420 million years old, that almost certainly means that the oldest plants (on land) are about 420 million years old.
That renders any estimate from the much less reliable molecular clock method for dating invalid if it contradicts that estimate of 420 million years.
They have discovered NOTHING;
humy
1 / 5 (1) Feb 20, 2018

They have recovered NOTHING;


Misedit;
that should have been;

"They have discovered NOTHING; "

Spellcorrector not good.
Rational_Thinker
1 / 5 (3) Feb 20, 2018
Supposition upon assumption based on hot air. But all necessary for the next research grant
FieryFly
not rated yet Feb 26, 2018
So if the science is off.. its because.. plants were around much longer than previously thought.. planet is 4.5 billion old.. the planet cooled much faster than previously thought.. oceans and microbial life sooner.. so plants a quarter of that is reasonable to assume.

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