Exploring Plants | Compilation

Here on Nature League, we explore the amazingness of life on Earth. While we try our best to highlight different species and ecosystems, we couldn't possibly pass up digging in deep to one very special kingdom of life on Earth... plants. To start this topic off, we explored the origin of plants, how they're related, and their incredible adaptations. Imagine a place on the surface of Earth. Unless you thought of a certain polar region or some very harsh deserts or mountaintops, that place contains some plants. And plants are more than just widespread. They're one of the main reasons that other species are widespread, too. Plants not only provide oxygen, but serve as the ultimate food source for most animals on land. But if we're going to talk about plants, there are so many more things to discuss than just what they do for other organisms. Plants are incredible in their own right, and possess so many stunning adaptations and life histories that we could never begin to detail them all. So, for this plant-themed lesson plan, we'll discuss some basic and advanced aspects of this remarkable group of organisms. Let's start with the origin story. Most lines of evidence suggest that land plants are most closely related to green algae, and that both most likely evolved from a common ancestral alga. The first plants were most likely small and unicellular, much like their closest algae relatives. However, there are currently close to 300,000 known species of plants on Earth, and these now include all kinds of shapes, sizes, and varieties. Let's check out the diversity of plants by looking at one currently proposed phylogeny, or evolution and relationships of a group of species. The first split on the plant phylogenetic tree is between vascular and nonvascular plants. Nonvascular plants lack extensive developed tissue systems that help move water and nutrients around the plants. These are commonly called bryophytes, or liverworts, mosses, and hornworts. Vascular plants make up all of the rest. In fact, close to 93% of all known plant species are vascular. These species can either be seedless or seeded, and that's the next big split in the tree. Seedless vascular plants include lycophytes, which include club mosses, and monolophytes, which include ferns. So our last and largest group of plant species are vascular and have seeds. But not all seeds are created equal. The last big split in the plant phylogeny has to do with the type of seed, specifically, whether or not the seed has chambers during development. The two groups of seed plants are gymnosperms and angiosperms. Gymnosperms have seeds that are not enclosed in chambers. In fact, the prefix gymnos means naked, so yep, naked sperm it is. Angiosperms have seeds that develop inside of chambers, and these chambers typically come from flowers. So angiosperms are also referred to as flowering plants, and they make up close to 90% of all plant species. Now that we've learned a bit about how different plants are related to one another, it's time to dive into one of my favorite things about any group of organisms, their adaptations to life on Earth. Back in the day of that ancestor algae, at least one population accumulated certain traits that allowed individuals to live on land instead of in the water. These populations would eventually evolve into the first land plants. And just imagine what that transition would be like if you were a photosynthetic organism. Underwater, the sunlight is filtered by things like plankton and the water itself, but on land, these starter plants could enjoy the sun undiluted and pure, getting way more than was possible underwater. Life on the sunny side of the street came with some disadvantages, however. Being out of the water meant that obtaining water became more of a challenge. Also, living on land means living with more gravity, and that put extra stress on plants' external and internal structures. The difficulties of living on land put selective pressure on newly arising mutations, which, over time, led to some of the incredible adaptations we see in the plant kingdom. Let's check out some of these plant adaptations for life on land. The move on to land meant that plants were permanently exposed to the air, and drying out was a major concern. And it's not like plants could just grab some lotion. Except they kinda did. Many plants evolved a covering called the cuticle, which contains wax. That wax compound is hydrophobic, meaning it doesn't dissolve in water, so the water is kept inside. Brilliant, right? Not only did they figure out waterproofing, but plants ended up with another special adaptation on their outer layer. Most plants have special pores called stomata. These openings allow the plant to exchange things like oxygen and carbon dioxide with the air. But water can evaporate from stomata, and that can lead to dehydration. Not to fear, though. Stomata have special mechanisms that allow them to actually close when it's hot outside. Nice one, plants. And while land plants have come a long way, the earliest versions didn't exactly have fully formed roots and leaves, and this meant trouble in terms of getting nutrients. So instead of a physical adaptation, why not a behavioral one? Why not, say, phone a friend? That's exactly what some of these early plants did. They teamed up with special fungal networks called mycorrhizae to get nutrients transferred from the soil to the plant. Teamwork made the dream work. And for plants, that dream was eating, surviving, and colonizing land. Although these adaptations absolutely helped ancestral plants make the move from water to land, the big game changers didn't appear until seeded plants. These adaptations are seeds and pollen grains. So what's the big deal? Well, plants aren't quite known for their movement ability, and that meant things had to get creative when it came to sex. Seedless plants like ferns have sex cells that use water as protection, and this is one reason why these species typically live in wet environments. With seed plants, the female sex cells are inside ovules, and the male sex cells are inside pollen grains. And unlike swimming sperm of seedless plants, pollen grains can be carried on the wind or by other organisms, meaning that plant sex didn't have to rely on having water around. Seeds themselves develop after fertilization, and they consist of the embryo, a food supply, and a protective coating. So not only did the evolution of seeds mean less reliance on water, but it meant that seed plant embryos had way more protection. A nicely packed lunch. And the ability to stay dormant for days, months, or even years before emerging. And as cool as seeds are, the most famous reproductive adaptations of plants belong to the angiosperms. That's right, we're talking about flowers and fruits. Flowers are unique structures made up of up to four kinds of modified leaves. Flowers allow the transfer of pollen from one individual to another in a way that's less random than just blowing in the wind. The different types of modified leaves that can make up flowers have different roles for aid in sexual reproduction. For example, petals are brightly colored, and this serves as a way to attract pollinators. So what about fruit? Angiosperm seeds have extra protection in the form of a thickened ovary wall. The ovary matures into what we call a fruit. Fruits don't just protect seeds, but they also help them get dispersed. This can be done in several ways, and if you've ever eaten fruit, you've been a part of one of those mechanisms. Amazing adaptations and unique reproduction aside, one of the coolest things about plants as a group is that they are truly creatures of two worlds. Think about it. Unlike almost any other life on Earth, plants are simultaneously living above and under the ground. The parts of the plant above ground take in things like carbon dioxide, whereas the parts underground take in nutrients. The entire plant concept depends on living in both environments, which is insane when you consider that plants are so well known for their relationship to the sunlight. All of this, and we haven't even touched on the craziest thing. Plants eat sunlight and carbon dioxide and poop oxygen. What even is that? If you ever want to feel like a slacker, just compare yourself to what plants are doing just by pooping. Plants are absolutely amazing, and we look forward to exploring this theme throughout the month. We film in western Montana, and there was no way we could discuss the plant kingdom without taking a field trip to the forests of the Rocky Mountains. We went and investigated this species in Glacier National Park, known for its beauty and spanning landscapes. However, the species here are under many threats, and we investigated these while there. Growing up in Florida, I often dreamed of coming out here and seeing the forests that define the northwest United States. Since moving to Montana, I've been inspired by all the tree species that call this region home. However, forests here in Glacier National Park and in surrounding areas are up against a lot of challenges. The U.S. National Park Service names three main threats to the forests of these regions. There's no better way to learn about these threats than to see them up close and personal. Glacier National Park is named for... Spoiler alert, it's glaciers. However, because of warming trends being seen globally, the namesake of Glacier National Park potentially will go away. Experts are predicting that potentially around the year 2030, all of the glaciers in Glacier National Park could be gone. Even though warming is being seen pretty much in all reaches of the globe, because of the latitude and also the geographical location of Glacier National Park, the rate of warming is actually happening 1.8 times faster here than the global average. Because the temperatures here are changing more rapidly than the global average, that means the plants and animals that live here are being forced to either move, adapt, or die. Plants in particular are being affected because unlike animals or other organisms that can move, plants pretty much stay where they are. And that means they rely on their water from things like the rain or the snow. With a warming climate, there's actually more rain than there is snow. Rain moves faster through the system, and that is leaving plants basically in drought conditions. In addition to droughts, changing temperatures, and fires, pathogens are one of the biggest threats to the forests in this area. One of the main pathogens is an insect called the mountain pine beetle, and it's a kind of bark beetle. Pine beetles are native to this region. However, changes in climate and other situations with the environment have made it to where they are causing way more damage than normal. Shorter winters and also warmer temperatures means that not as many of them are dying over winter, and so there's way more of them and they're attacking more trees. Drought also has something to do with this. Plants that are stressed out by drought conditions will actually be more susceptible to pathogens. Fire comes into the story as well. When trees are in drought conditions, they'll be stressed, which leaves them susceptible to pathogens, which then can kill them, which then can provide a lot of fuel for fires. And fires have been increasing and causing massive destruction around these parts. So if you look at the big picture, all of the threats to forests out here are really kind of working synergistically, and this means a lot of different complications for managers and people making decisions about what to do to protect the forests. And now a word, not from our sponsors, but from the dictionary. Welcome to this month's Wild Word. Once a month on Nature League, we'll look at the etymology, or origin and history, of words related to nature. This month's theme is plants, and there are simply way too many interesting etymology stories within this theme to just pick one word. So for this month's Wild Word, we're doing a lightning round of some of my favorite plant names. Let's go. Daisy. This is actually a contraction of the Old English phrase, digizige, meaning day's eye, named for the fact that daisies open during the day. Tulip. From the Turkish, tulbin, and Persian, dulbin, meaning turban, for the shape of the petals. Chrysanthemum. From the Greek, chrysos, meaning gold, and anthemum, meaning flower, this is, in fact, a golden flower. Dandelion. From the Latin, dens, meaning tooth, and leo, meaning lion, or more recently, the Old French phrase, dandelion, which means lion's tooth. This name comes from the toothed leaves of the plant. Lavender. From the Latin, lavare, meaning to wash, lavender was historically used as a scent for fabrics and baths. Eucalyptus. From the Greek prefix, eu, meaning well or true, and calyptos, meaning covered, this describes the covering on eucalyptus buds. Basil. From the Greek, basilius, meaning king, basil is believed to have been used in royal perfumes. Another option has to do with a mythical creature called a basilisk. Some myths note that basil leaves could cure a deadly gaze from a basilisk. In fact, in Latin, both the monster and herb are called basiliscus. Pansy. From the Latin, pansare, meaning consider, pansies have been used throughout time as a symbol of thoughtfulness. Orchid. This one is good. From the Greek, orchis, meaning testicle, this name comes from the shape of its roots. As you can see, there are some really fun word origins and histories of plant names. And with hundreds of thousands of plant species on Earth, there are way more stories than the ones we've looked at here. And all of that is pretty wild. The plant and forest communities out here in the Rocky Mountains are incredible. However, these systems are rapidly changing due to threats like changing temperatures, fires, droughts, and also pathogens. Some people view these changes as something to be mourned, while others view it as just another example of a system changing over time. Either way, the decisions facing forest managers in light of a changing climate are complicated. However, I think these systems are worth the time and effort required to figure it out. One of the most talked about plants on Earth is marijuana, both for human recreation and medicine. We next explored the theme of plants in a format called Denatured, where I broke down a popular peer-reviewed journal article on the effects of chemicals and cannabis on brain regions associated with psychosis. For this month's Denatured segment, we're going to look at an article released in August 2018 in the Journal of the American Medical Association Psychiatry. This month is all about plants, and in this month's lesson plan, we began by mentioning that most organisms on Earth depend on plants to live. Not only do plants provide oxygen to the atmosphere, but they serve as the energy starting point for many living food webs. But in the realm of human medicine, plants and their isolated compounds can yield much more than oxygen and food, especially in the case of cannabis. In this paper entitled Effect of Cannabidiol on Medial Temporal, Midbrain, and Striatal Dysfunction in People at Clinical High Risk of Psychosis, the researchers report the results of a new clinical trial that investigated how cannabidiol, or CBD, can affect individuals at high risk of psychosis. So here's what's already known. Cannabis is a genus of flowering plants, plants that have been used by humans for thousands of years for a multitude of purposes. Two well-known varieties of plants of this genus are commonly known as hemp and marijuana. Two chemical compounds have contributed to the well-known nature of cannabis plants. The first is cannabidiol, or CBD, and it's primarily found in hemp. The second compound is tetrahydrocannabinol, or THC, and it's primarily found in marijuana. While both compounds have the exact same molecular formula, THC is psychoactive, meaning it can create a high or euphoria. But what do cannabis plants have to do with psychiatry? That's where brain chemistry comes in. The reason our bodies react to CBD and THC at all has to do with the fact that human brains have an endocannabinoid system. Alterations in this system are associated with the symptom of psychosis, which can be generally defined as a loss of contact with reality. While some research has shown that regular cannabis use can be a risk factor for developing psychosis, especially in teenagers, these findings specifically refer to THC. The other compound, CBD, can actually have the opposite effect. In fact, some clinical studies have shown that CBD has anti-psychotic properties for people with certain mental disorders. Despite a growing body of evidence that CBD can be beneficial to those suffering psychotic symptoms, scientists have yet to figure out how. To address this, the research team observed the effects of CBD on three specific regions of the brain in people at clinical high risk of psychosis. The first of these regions is the medial temporal lobe, or MTL, and its primary function has to do with new learning. The other regions are the midbrain and striatum, which also contribute to learning in the form of helping to encode and update information in our memory. To observe the effect of CBD on the brain, the team had participants perform something called the Verbal Paired Associate Learning Task, or VPA. Participants at clinical high risk of psychosis, referred to as CHR, were recruited, as well as healthy control participants who were not at CHR. For the purposes of this video, we'll refer to CHR participants as high risk participants to get away from being too bogged down in initializations. In the study, high risk participants were randomly assigned to a CBD treatment or placebo treatment. After taking the assigned drug, participants performed a VPA task while having their brain scanned using functional MRI. The healthy control group didn't receive any drug treatment, but they still did the tests and the imaging. But what exactly did the VPA task entail? It actually has three separate testing conditions, encoding, recall, and baseline. During encoding, participants answered yes or no to whether a pair of words went well together. So for example, sharks and awesome, definite yes. In the recall condition, participants were shown one of the words they saw during the encoding, and asked to say which word it had been paired with. The baseline bit was a control of sorts, where the participant looked at a blank version of the setup they'd seen during encoding and recall. The response of the brain during the VPA task was measured using fMRI. Specifically, the scan measured the blood oxygen level dependent, or BOLD, response of the brain. Basically, this allowed the researchers to measure the flow and composition of blood in the brain during the encoding and recall parts of the VPA task. Then, they could compare these responses to the baseline results. So what did they find? Overall, high-risk participants who were assigned a placebo had several regions of the brain activate differently than people in the control group. Similar to previous studies, these regions included the three thought to be associated with psychosis. The specific hypothesis the team was testing was whether participants at high risk who were given CBD would have a level of brain activation in between the activation levels of the control group and the high-risk group who were given the placebo. The team did find this middle ground activation in the striatum during encoding, and in the parahippocampal cortex and midbrain during recall. These results suggest that for these specific brain regions, CBD may help normalize brain responses in individuals at clinical high risk of psychosis. This article was published in one of the most prestigious families of medical journals. In addition to academic circles, the results have made headlines in the news as well. Here are some reasons why I think this study is captivating both scientists and citizens. First of all, the results are directly relevant to helping humans. Unlike some other articles that we've discussed on denatured, this study has a direct human induce, and an important one. Mental health disorders affect people in every walk of life, and in the case of psychosis, as many as 3 in 100 people in the U.S. will experience this symptom at some point in their lives. Another reason I think this study made the cut is because the research team was the first to do something. In this case, they were the first to give evidence of how CBD acts in the brain to reduce psychotic symptoms. This is a major level up from just knowing that CBD can reduce these symptoms. And of course, whenever there's a promising discovery in the medical field, there's the potential for profit. There's a growing body of literature supporting the use of CBD for medical purposes, and that means major money for those involved in supplying the product. In the United States alone, hemp-derived CBD is predicted to soon become a billion-dollar market, and that's even without federal legalization. There is undoubtedly a lot of gain from using this particular plant product for medical treatments, and money is certainly part of that gain. The devil is in the methods section when it comes to issues in experimental design. However, this research team did a great job of removing potentially confounding variables and removing bias where possible. For example, the study design was parallel group, double-blind, placebo-controlled, and randomized. Randomization allows the researchers to remove the bias that comes from assigning specific people to specific treatments. It's picking names out of a hat instead of, say, because you like their asymmetrical haircut. Double-blind trials are ones where the participant and the researcher aren't in on who was assigned which treatment. That way, the researchers are less likely to be looking for certain associations. If a researcher knew a participant had been given the CBD, they might start looking for some kind of result or jump to conclusions unintentionally. We just can't help ourselves when it comes to investigating things. It's impossible to not start explaining what we see, and double-blinding a trial is a great way to avoid that. What about the parallel groups bit of the research design? This piece is actually more of a limitation of the study. In parallel group studies, each participant only receives one of the treatments, and then those people are compared to separate individuals who receive the other treatment. In this study, this meant that the high-risk participants either received the CBD or the placebo, but none of them were actually observed under the effects of both. With this kind of non-crossover design, the baseline is a bit iffy. I mean, just think about how different we all are when it comes to chemical reactions. Take alcohol, for example. Comparing you, sober, to a friend who's had a bit to drink might be a completely different story than if you reversed the roles. Luckily, the researchers do an awesome job of pointing out limitations like this in the discussion section of the paper. They mention the issue of the parallel design structure, and suggest that a study be done where each high-risk participant be tested with both the placebo and CBD treatment. That said, they mention that the two high-risk groups were reasonably similar in terms of demographics and baseline health measures. This does, however, lead me to another critique of the study, and that is the sample pool of participants. One potential problem area has to do with the sample size. There were 15 high-risk participants assigned CBD, 16 high-risk participants assigned the placebo, and 19 age-matched healthy controls. While these numbers do allow for testing statistical significance at the cutoff levels the team was interested in, more is always better when it comes to determining the strength of an effect. There's also the issue of diversity. In the table showing sociodemographic measures, the paper only reports age, sex, and education level. However, there's no mention of variables like race and ethnicity, meaning that this could be yet another psychiatry study done on a Caucasian sample. Conducting research on participants of varied backgrounds is essential to understand the full picture of drug-brain interactions. Here's the thing. Humans and non-human animals have been using plants for medicinal purposes throughout the history of their time on Earth. Understanding how the chemicals in certain plants can affect our brains is a really complicated area of research, and a study like this one is just a single piece of that journey. As the research team put it themselves, this wasn't so much of a clinical study as it was a proof-of-concept pilot study. It's exciting to imagine what we might find next when it comes to this amazing kingdom of life on Earth. We couldn't complete the topic of plants without letting my friend Adrian ask me a question about this kingdom of life. In this installment of From A to B, Adrian asked me about the morality of eating plants versus animals. This month, we've been talking all about plants. You have a question for me regarding that group of organisms, yes? Yes. Why is it morally acceptable to eat plants when it's not acceptable to eat animals, huh? Plants respond to stimuli just like animals do. They live, they die, they have babies, they make oxygen and stuff. Animals don't do that. No, they don't, see? So what are animals doing? Pooping. You brought up some differences between plants and animals generally, but none of them to me were quite what might be at the source of the moral conflict, and the moral conflict has to be about harm. I think that when it comes to, like, suffering and harm, it really is a matter of pain. Would you agree with that? Sure, yes. We know that humans experience pain on a ton of different levels. We know the difference between a scratch, a deep wound, a burn, a cut, a blunt force trauma. We feel all these things, and pain is very complex for us. But that might just be because our brains are really complex. What about those lesser organisms? How do we know that they experience pain on this level that humans do? So lesser meaning less complex? Yes. How do we know that they, what they even experience is pain? How do we know they don't just, you know, that spider doesn't just go, oh man, I lost that leg, I'll use it to play golf later. It's cool. Well, probably because no spiders ever said that in the history of arachnids. That you've seen, that you've seen. You're right, I'm being hateful. Spiderist. You mentioned different kinds of pain, and you were saying the differentiation that we can have like surface level and deep, and that is not actually coming from just the brain, but that is actually anatomically wired in. There's different literal infrastructure in the skin, in the dermis, that tells us about deep pain versus, or not deep pain, but deep sensation versus shallow sensation. And then from there, pain is caused because something disrupts a nerve, so nerve tissue. Sure. It's not just the complexity of the brain, there's complexity in the anatomy. So that's one of the things we see with a, maybe more complex on the tissue level, kind of an organism. The fact that there could be differentiations in the types of cell lines that are then able to receive. But the big, big piece here, I think, is nerve tissue. So nerve cells, nerve tissue, and brain, which is where a lot of people are saying, oh, well, how can pain happen if there's not this, you know, not only like a central nervous system, something that's controlling and calling the shots, but also tissue that itself responds. Plants don't have nervous tissue or nerve cells in the same way that mammals do, or some other organisms. Plants are unique on every level, right? But plants are still doing a lot of really cool things. I know. You know, you watch a plant on a video camera and you speed it up, they're doing some crazy stuff, following the sun or closing their leaf petals, because they're like, time to go to sleep, or whatever plants sound like. Probably that. Probably like this. Oh, look at me. I'm a hydrangea. I think you just brought up a good point about what plants are doing. You just named two specific things that you might see a plant do movement-wise, which is something called phototaxis, so moving toward a light source. You also mentioned something about like closing down. So sometimes there needs to be protection from both dehydrating, because there's open pores in plants that then they can lose things like water. So there's all kinds of adaptations. But with pain, why does something feel pain? And by that, I mean, evolutionarily, what is adaptive about feeling pain? To retreat away from something that causes you harm. And do plants move? Hightail out of anywhere. They're rooted. So in terms of adaptations and evolution, would it be advantageous for a plant to dedicate tissue and cell lines to being told to get out of there? That's a sick joke, right? They're like, I'm trying. They just die. I have roots. Oh, no. So what you're telling me is don't lay down roots. Get attached to no one. Live in a bunker in the woods. Live off the grid. So the closest we see to movement is, again, to the sun, which there's adaptive there. Chasing food. Yeah. But then like Venus flytraps, the trigger mechanism, right? That's not a brain or anything that's being like. Those are just little fibers on the inside. So I would like to challenge us. I would like to challenge us to open our minds to the ideas of what a brain might look like if you don't have nervous tissue. Perhaps it is things like a little diddly, diddly, diddly, those, right? Perhaps that is functioning like a nerve cell, like a neuron. There's also been work recently where we found that the signal received by one leaf on a plant can actually be transmitted to another. Totally. So there's a network. And what else is a nervous system if not a network of response bits? So. TLDR, too long, didn't read for those of you who do. I didn't know what that meant. Anyway, so what you're saying is the whole plant is its own little brain. I'm saying it could be. I'm saying we should open our minds up to what a brain is, and then perhaps we get to a different place in terms of what we believe pain might be, which then might inform these ethical and moral questions about causing pain to this versus causing pain to this. Because at the end of the day, pain is usually in the form of some form of tissue being impacted, and then you have chemical and physiological responses to that impact. Even if no literal impact happens, if it's a mental and then a manifested, still there's reaction. We see plants react to all kinds of things all the time. I know. It's so complicated. They should really dedicate a field of study to plants. Here's looking at you, botanists. So I would say in general, wherever those moral lines lie, there are certainly differences anatomically, physiologically, but also in our own minds and the way that we view and perceive things that happen in spaces and brains and bodies that we will never know from our own perspective. And that's kind of cool. So eat all the plants you want. Yeah. And then throw your poop out the window. I don't endorse that. Get out of my camera. Plants are truly incredible, and the more we learn about this kingdom of life on Earth, the more we discover their amazing uniqueness. Thanks so much for watching, and if you'd like to keep going on life on Earth adventures with us here on Nature League, make sure to go to youtube.com slash nature league, subscribe and share. Hey guys, we now have a Nature League pin on dftba.com. Click on the link in the description below to get yours.