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Go to Brilliant.org/SciShow to check out their Scientific Thinking course and for 20% off an annual premium subscription. [♪ INTRO] Most of us are pretty close to our tech. Maybe you wear a smartwatch or use your phone to track your sleep patterns.

But some scientists want us to get really close with machines integrated into our biology to make more intelligent medical devices. And although those visions are still a ways off, more and more scientists are uncovering how to make that jump. A way to get humans and technology closer is by learning how our brain cells communicate through electrical and chemical signals.

After all, our brains, structurally at least, are pretty similar to organic semiconductors and have a lot of flexibility when it comes to the stuff they can sense or control. So learning how all that works is key for application later on. And researchers might have added another rung to that ladder in a study published this week in the journal Nature Communications.

They created artificial brain cells, also known as neurons, and connected them with a Venus Flytrap plant. Although plants do not have brains or a neural network like us, their ability to close their trap is controlled by the right levels of both ions and electrical stimulation, a lot like a neuron. And that trap-closing mechanism has been well studied, so researchers know how to tweak it for experiments like this.

Now, I’ve mentioned ions and electricity and neurons a few times, so it might pay to do a quick recap of how neurons work. Neurons communicate by shuttling ions, positively or negatively charged atoms, through tiny tunnels between the neuron’s inside and outside. Because of the cell’s membrane structure, where it’s “leakier” to some kinds of positive ions than others, more positive potassium ions flow out of the cell, making the insides slightly negatively charged.

So, when neurons fire, those tiny tunnels between the inside and outside open, and more positively charged ions rush inside, creating an electrical charge and a spike in the neuron’s voltage. That electricity burst is turned into chemical signals at the end of neurons that jump the synapse, a gap between the cells. On the other side, receptor molecules on the second neuron convert those chemical signals back into electric charges so that the second neuron can continue relaying the message.

So researchers involved in this week’s study made an artificial device that works just like a biological neuron. They printed artificial neurons made out of polyester and some metals that act as ions onto a tiny plastic base. The setup is called organic electrochemical neurons and synapses, or OECNs.

And they worked just like real neurons, creating spikes in electricity to communicate with one another across synapses using ions from printed metal. And here is where the Venus Flytrap comes in; scientists connected the synthetic neurons to the flytrap’s cells using super thin wires. When researchers pulsed electric signals through the neuron, it activated the plant’s closure mechanism, and the flytrap snapped closed!

Like, the researchers could adjust the frequency of electrical pulses the neuron sent to the plant. Only when the pulsing was fast enough did the flytrap snap close. So the artificial neurons relay the message just like a real neuron in a brain would.

Plus, because the artificial neurons are printable, they’re pretty low cost and easy to make. And there are bunches of cool applications that you could do with this technology, from wearable devices and brain-computer interfaces to maybe even biolimbs that look and function and act like the limb they are replacing. So who knows, the line between biology and technology might just be getting that little bit thinner.

But some other animals might have technology already built into them, in the form of weapons. Deer have antlers as weapons, crabs have snappy claws, but birds have to make a big decision: to fly or to develop specialized weapons to defend themselves. And researchers published this week in the journal Ecology Letters that their decision comes down to plain ol’ evolution.

Animals can have different routes of evolution: for example sexual selection, where a bird pushes evolution by preferring a specific attribute like flashy feathers in a mate. Or it can go down the natural selection route where birds adapt to their environment by doing things like growing long or short beaks. These adaptations of getting a mate or getting cozy in their environment often go hand in hand, but researchers found that that is not the case for most birds.

In fact, just a small percentage, of about 1.7 percent, carry weapons in the form of a bony spur in the leg. And the reason why that percentage is so tiny boils down to the flight part. Researchers studied around 10,000 birds and measured the hand-wing index, or how far their wing shape extends, which tells you how good a bird is at flying.

And they found that birds with a high index did a great job at flying and did not have the spur, but the ones that did have spurs had a harder time flying. After running computer simulations, researchers found that birds had to pay a big price, evolutionary speaking, to have that spur. Researchers think that birds with that extra structure make up so few birds because it makes flying really hard, so they have to spend extra energy to take off and fly away to escape.

So when danger is around the corner, birds with spurs take longer to escape, upping their chances of becoming dinner. While the ones that went with the flashy feathers, fancy songs, and weapon-free flight could flee danger at a moment's notice. So, in a sense, birds woke up and did not choose violence.

They chose flight. And if you want to understand life’s other patterns you can check Brilliant’s Scientific Thinking course. Brilliant is an online learning platform with courses in science, engineering, computer science, and math.

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