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This week, scientists think they may have found a missing link in regards to how plants went from living in the sea to on land, and also, in adorable news, surfing honeybees.

Hosted by: Hank Green

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Sources:

https://www.cell.com/cell/fulltext/S0092-8674(19)31169-9
https://www.nytimes.com/2019/11/14/science/plant-genes-evolution.html
http://www.biologyreference.com/Ep-Fl/Evolution-of-Plants.html
https://www.sciencemag.org/news/2019/11/alien-genes-bacteria-helped-plants-conquer-land
https://www.intechopen.com/books/abiotic-and-biotic-stress-in-plants/biotic-and-abiotic-stresses-in-plants

https://www.pnas.org/cgi/doi/10.1073/pnas.1908857116
https://schoolofbees.com/how-do-bees-collect-water/
https://www.boatus.com/magazine/2018/april/hydrofoils.asp
https://www.eurekalert.org/emb_releases/2019-11/ciot-ba111419.php
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Go to Brilliant.org/SciShow to learn more. [ intro ]. There’s a lot written about how early animals transitioned from living in water to living on land.

But you rarely hear how /plants/ did it. That’s kind of a shame, because plants reached land first, and they conquered the planet way faster than animals. Also, without them, you and I really wouldn’t be here.

Unfortunately, the earliest land plants didn’t leave much fossil evidence behind, so their story isn’t that clear. To know what these plants were like, scientists have to hunt for clues in the DNA of today’s plants. And last week in the journal Cell, one team shared an exciting new finding.

They analyzed all of the genetic material in two species of algae that are closely related to land plants. And by doing so, they might have discovered how early plants managed to survive in the open air. Sidenote, I just want to emphasize how hard it is to go from living in the water, where all chemistry happens -.

This research focused on a class of algae called, wait for it,. Zygnematophyceae. Put it on the screen there for ya, didn’t I do a good job?

Recently, scientists found that this type of algae shares a lot of genetic material with the first land plants, so they’re probably closely-related. This is early work, though, so in this new paper, the first thing researchers did was look for more evidence that it’s true. To do this, they sequenced the genomes of two early types of Zygnematophyceae.

In other words, they analyzed and created lists of the stuff in the algae’s DNA. Then, they compared those lists to the genomes of land plants and a handful of other algae species. The team found that the early algae shared a bunch of genes with land plants: a whopping 902 of them.

But the other algae species didn’t have these genes. That suggests those genes evolved before Zygnematophyceae and land plants branched off from each other about 580 million years ago. And it all but confirms that this class of algae represents the closest living relatives to land plants.

And That’s great news, because it’s super satisfying to figure out how things are related to each other. I mean, who doesn’t like a nice, complete family tree? But the team also found something else in their data — something that might explain how early plants managed to survive on land at all.

They noticed something weird about two families of genes in that list of 900. They were the genes responsible for helping plants cope with the stresses of living in the open air, like drought or pests. But they didn’t just appear in land plants and those two species of algae.

After searching a large database, the scientists also found these genes in one other group — just one. Soil bacteria. That might feel like it comes out of nowhere, since bacteria, algae, and land plants aren’t that closely related.

But the team had an explanation for how it might have happened. Bacteria are big fans of exchanging their DNA through something called horizontal gene transfer. It’s where they pass genetic information not from parent to offspring, but from one organism to another, unrelated one.

Bacteria do this fairly frequently. So the team proposed that at some point, soil bacteria passed the genes for surviving on land to the common ancestor of land plants and Zygnematophyceae algae. And eventually, that may have given plants the adaptations they needed to survive and take over the world.

Or at least the land parts of it. Now, this hypothesis isn’t bulletproof, and the idea of bacteria transferring genes to more complex organisms is kind of controversial. Any positive results are often blamed on contamination.

But among other things, this team took safeguards to avoid that. So at least for now, their results are getting some researchers pretty excited. After all, now that we’ve spotted these bacterial genes, we can learn more about how they got there and how they evolved to help land plants.

And as a result, we can learn how the Earth became all beautiful and green and leafy and stuff. In any other news,. Caltech researchers announced on Monday that they discovered a skill in honeybees that’s never been seen in any other insect.

And honestly, it’s pretty cute. Apparently, honeybees can surf on water. At least, in a sense.

If you’re an insect with wings, water can be dangerous. With one touch, your wings can be trapped by the water’s surface tension, and that takes a huge amount of force to overcome. Often, insects just end up drowning.

But for honeybees, going for a dip is not a death sentence. The Caltech researchers found that, when honeybees fall into water, they can carefully alter their wingbeats to surf their way to safety. They confirmed this by setting up a shallow pool of water illuminated by filtered light, so that any waves cast visible shadows.

Then, in went the honeybees. Thirty-three bees each took their turn surfing. And they did something super cool.

They used their wings as hydrofoils — surfaces that can generate lift in water, kind of like what airplane wings do in the air. With the underside of their wings stuck to the water, they flapped against the surface with slow, shallow strokes. To illustrate, an average flying honeybee flaps its wings between 90 and 120 degrees and about 250 times per second.

But in water, most of these bees moved their wings about ten degrees, and less than a hundred times per second. Almost like a honeybee doggy paddle. That created a pattern of waves behind the bee that propelled it forward.

The insects couldn’t do this forever, of course. In the experiment, they flapped around for a few minutes, and then the researchers scooped them out and gave them some well-earned rest. But in nature, one scientist estimated that a honeybee could probably keep this up for about ten minutes.

And that could be enough for it to get to safety. This research is super adorable, but the team behind it is hoping to take a page from the insect’s playbook, too. They’re already applying the bee’s surf style to robotics research in hopes of creating a robot that can navigate both air and water.

So, thanks, bees! Just another reason to appreciate you. If you want to learn more about some of the science topics we talked about in the video, you can check out a course from Brilliant.

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So thanks for considering it! [ outro ].