Welcome to brain Stuff from How Stuff Works. Hey, brain Stuff, it's Christian Seger. So there's this old episode of Star Trek called Wink of an Eye. You may have seen it. There's this race of aliens that live in hyper sped up acceleration. So when the crew of the Enterprise appears to meet up with them, they seem so slow that they're unable to move. Now, imagine that scenario. If you were the aliens, wouldn't you assume humans were inert objects
with no consciousness. Now let's take this and apply it to our relationship with plants. When we watch videos of plant life sped up, we see their lively movement. But even though plants move and respond to stimuli, they're not conscious. Right, Otherwise, every time we ate vegetables, we'd be causing them pain. Wait, wait a minute, can plants feel pain? Well? Okay, there was this guy once. His name was Charles Darwin. You might have heard of him, and he once proposed something
called the root brain hypothesis. He proposed that the tip of a plant's root could act like a brain does in some animals, receiving sensory input and directing movement. In the years since Darwin made this proposal. There's been a growing movement in science called plant neurobiology, and it debates the way we think about plants and consciousness. Other scientists hate this term, but who cares, because here's some of the things we know about plants because of this really
unusual research. Let's start with plant senses. We know that plants have a variety of sense some that can actually act as analogs to our site smell, touch, taste, and hearing. In fact, there's evidence that when plants hear the sound of a caterpillar chewing on a leaf, they respond defensively by producing chemicals like mustard oil. This happens even if the sound is a recording and nothing is eating the plant. Creepy, right.
Plants can also communicate sometimes. Plant chemical production is like a method of communicating with other plants. So here's an example. That smell of freshly cut grass that we all know that's actually a distress call to warn other plants of danger. It's true in gardens, no one can hear you scream. Now, when this distress call reaches other plants, they will also emit the chemicals to warn their neighbors as well. And these calls can even work on different species of plant.
For instance, a sage plant can signal a tobacco plant to emit an odor that's not just to animals that are eating the sage. All right, So you hear the term plant neurobiology and you say, but plants don't have brains. Well, one of the reasons why many scientists hate that term is because plants don't have neurons, but they do produce neuroactive chemicals that act like those in the human brain.
Glutamate receptors form memories in humans, and they're also found in plants, and some hormones are transported around plants similar to how neurotransmitters move through animal brains. Likewise, some plants are vulnerable to drugs that disrupt neurotransmitters in the human brain, like prozac or meth amphetamines. They even produce their own ethylene, which is possibly used as an anesthetic when they're stressed out.
Plants even have a kind of nervous system, and that may allow information to travel around the plant via electrical sick mills. So if plants have sort of brains, do they remember stuff? Well, yeah, plants also have their own kind of memory. In fact, there's a plant called the Mimosa pudica plant, and it closes its leaflets immediately after they're touched, but because this requires energy, the plant won't
do it if it's unnecessary. However, when researchers dropped potted mimosas fifteen centimeters onto foam, the plants learned that the fall wasn't dangerous, so they stopped closing their leaves. Even crazier, after one month, the plants still remember that the drop wasn't dangerous and they wouldn't close their leaves in response. So, given what we know about plants, senses, communication, nervous systems, and memories, should we consider them to be either conscious
or intelligent? What about pain? Does the fact that plants react to danger indicate that they feel pain? Well, some scientists argue yes, while others loudly say no. Check out the brainstuff channel on YouTube, and for more on this and thousands of other topics, visit how stuff works dot com