Plants Took Over Earth's Land 100 Million Years Earlier Than Previously Thought

Monday, 19 February 2018 - 8:21PM
Monday, 19 February 2018 - 8:21PM
Plants Took Over Earth's Land 100 Million Years Earlier Than Previously Thought
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Flickr/Paul Downey
Most of Earth really belongs to the plants, who fill up nearly every nook and cranny of nature and generate the oxygen that we fauna need to survive.

For a long time, it was thought that plants first made their way to land 420 million years ago, when the oldest known plant fossils on land were formed. But new research now suggests that the first pond scum actually made its way to Earth's land 100 million years earlier than that.

Rather than relying solely on a still-incomplete fossil record, especially when plants typically don't leave behind fossils as comprehensive as animals do, a team used a molecular clock approach where they tracked mutations throughout various species' evolutions to see when they diverged from other species.

The results took them further back than what the fossil record includes, indicating land plants first evolved 500 million years ago, right in the middle of the Cambrian period. 

The research was published in the Proceedings of the National Academy of Sciences. According to Mark Puttick, a co-author of the study, who said the following in a press release:

Opening quote
"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' approach to compare differences in the make-up of genes of living species - these relative genetic differences 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."
Closing quote

Of course, that was all natural evolution, and based on the mutations we humans are adding to plants these days, this sort of molecular clock approach wouldn't work as well if attempted on some modern plant species. Now that certain plants can light up, and especially if DARPA manages to genetically engineer plants into surveillance tools like they're hoping to, things are a little more complicated.

But it's important that we make these kinds of findings about plants. After all, they've absolutely influenced evolution for animals over the years, and this is (again) basically their world we live on.
Science News