Get Sleepy: Sleep meditation and stories - The Sleepy Science of Seed Dispersal

Starting point is 00:00:00 Get Sleepy is a production of Slumber Studios and is made possible thanks to the generous support of our sponsors and premium members. If you'd like to listen ad-free and access weekly bonus episodes, extra long stories and our entire back catalogue, you can try out premium free for 7 days by following the link in the episode notes. Now, a quick word from our sponsors. Hey friends, welcome to Get Sleepy, where we listen, we relax, and we get sleepy. My name's Tom, and I'm your host. I want you to know that just by being here and listening to the show, not only are you making the effort to ensure a good night's rest for yourself, but you're also supporting

Starting point is 00:00:58 the work of the whole team responsible for Get Sleepy. It really does mean a lot to us to know that the show resonates with you and I hope that the familiarity of listening to my voice and the voices of my fellow narrators as well as the soothing themes of our content all help to bring you comfort, reassurance and a bit of peace each time you tune in. This evening's lovely tale is no different. It was written by Delaney and I have the pleasure of reading it for you. If you've ever blown on a dandelion, watching all the fluffy white bits float away on the breeze, or picked up an acorn on a walk and dropped it somewhere else, you've been part of the process

Starting point is 00:01:56 known as seed dispersal. In essence, you've helped to move seeds from one location to another since you've helped to move seeds from one location to another where they have a chance to grow. Tonight we'll be diving into the fascinating world of plant science and learning about how different types of seeds move from place to place in order to thrive. place to place in order to thrive. So let's prepare to listen with a little bit of visualization paired with some focus on our breathing. So I want you to picture yourself standing somewhere out in the countryside, surrounded by sprawling fields of lush grass dotted with wildflowers. The sun glistens in the sky, its warmth caressing your skin and radiating through your whole body. Close your eyes here and let your face feel the direct touch of the sun's soothing rays. A gentle breeze floats across the fields and as

Starting point is 00:03:34 you stand there letting your eyes open back up you notice a scattering of dandelion seed heads in front of you, those puffy white spheres atop a small stem. Crouch down briefly and pick one out of the grass, holding it between your thumb and index finger. Take a deep breath in, of the dandelion as you do. Watch as several seeds dislodge from the stem, floating through the air and out of sight. Repeat this gentle course of breath a few times, breathing in nice and fully and softly blowing the air back out, freeing up more and more seeds to begin their journey on the wind to a new place. As these seeds float away in the soft breeze, you can allow any troubles, any tension that

Starting point is 00:05:32 you are feeling to peaceful and relaxed. And with that essence of peace flowing through us, let's turn our quiet attention through us. Let's turn our quiet attention to the interesting world of plants and learn more about the ways they disperse their seeds. This is where our story begins. A A warm gust of wind caresses a field speckled with fluffy white dandelions, lifting a few cylindrical seeds and their feathery white wisps into the air. A rough brown coconut drifts across miles of salty ocean currents. An ant dutifully marches to her nest with a seed tucked between her mandibles that she scavenged from beneath a wild ginger plant. A squirrel leaps through the forest with its cheeks stuffed full of acorns. At first glance, these snapshots of the natural world don't seem to have much in common. But if you take a closer look, you'll learn that these are all examples of seeds traveling towards the destination where they will eventually be deposited.

Starting point is 00:08:11 Once these seeds have completed their journeys, they will hopefully germinate and grow into plants. All living things are united by the same goal, to reproduce. In order to pass their genetic material to the next generation, great big sea turtles dig holes in the sand to lay eggs. Praying mantids create egg sacs that baby mantids will burst out of. And birds build nests of all shapes and sizes, where they will nurture their featherless chicks. These creatures are all ensuring that their offspring will be born in a location that increases their chances of survival. rival. Living things that can swim, walk, or fly are able to personally select the location where their young are brought into the world. But what about plants? What measures do they take to help their seeds end up in a place

Starting point is 00:09:50 where they might grow into plants of their own? A seed's journey from its parent plant to the site where it will ultimately be deposited is known as seed dispersal. Of course, a plant is unable to carry its seed to a location suitable for a new plant to grow. However, despite their sedentary nature, plants have evolved mechanisms that allow them to determine where their seeds will eventually end up. To do this, they have to rely on help from outside sources. Animals, wind, and water are just a few examples of the creative ways that plants have evolved to disperse their seeds. A successful seed dispersal journey ends with a seed being deposited in a spot where there are sufficient resources for it to germinate and grow.

Starting point is 00:11:17 These resources include adequate nutrients, high quality soil, water, and sun. Seeds also have a higher likelihood of germinating and thriving when they are spread out from one another. This reduces competition for resources produces competition for resources between related plants. For example, the seed of a large maple tree wouldn't have much luck surviving between the sprawling canopy of its parent plant. So, without pulling her deep roots from the soil and tiptoeing to another place in the forest to deposit her seeds, the tree will have to enlist some extra help. The natural world is full of helpers. Often, seeds are dispersed via a mutually beneficial relationship between an animal and a plant. These mutualistic relationships demonstrate a harmonious aspect of nature, one where favors are exchanged between two living organisms.

Starting point is 00:12:57 When it comes to seed dispersal, the animal is usually rewarded with a food source, while the plant benefits from having its seeds distributed to a suitable spot for germination. However, these helpers are not always living. Seeds can also be dispersed by non-living elements of the natural world, such as wind and water. Let's take a peek into some of the ingenious mechanisms plants have evolved to disperse their seeds. The dispersal of dandelion seeds is something you've surely seen, and may have even been an active participant in. If you've ever plucked one of these flowers from a grassy knoll,

Starting point is 00:14:07 If you've ever plucked one of these flowers from a grassy knoll, raised it to your lips, and blown with all your might, then you have helped increase the probability that the plant will pass their genetic material to the next generation. Many of us have been told to make a wish as we've loosened the seeds from their cluster at the center of the flower with the power of our puffed cheeks. The myth of dandelions granting wishes claims that your wish will be carried off into the sky along with the narrow cylindrical seed and its white feathery umbrella. Of course, dandelions rely on more than just humans who are eager to have wishes granted in order to disperse their seeds. The mighty force of the wind is also able to dislodge the

Starting point is 00:15:17 seeds from their fluffy clusters and sweep them across the sky. and sweep them across the sky. The seeds can easily become airborne thanks to a couple of different adaptations. First of all, most seeds weigh less than half a milligram, allowing them to be easily swept away by gentle gusts of wind. But what stops the seeds from dropping to the ground after becoming airborne? Dandelion seeds are especially good flyers, thanks to the feathery white tufts that are attached to each one. These delicate structures are known as a papus and are made up of around a hundred bristles attached to a thin white tube. When a summer breeze blows through a grassy

Starting point is 00:16:30 garden, field, or park that is speckled with dandelions, the papus tethered to each seed functions like a parachute, allowing it to take flight and travel through the skies. The seeds that are shaken loose by the breath of humans or gusts of summer winds typically drift through the sky for a couple of miles before lazily floating down into a grassy field. their passive flight can go on for up to 60 miles. Once their travels have come to an end, the seeds will hopefully find themselves in a place with the right amount of sun, water, and nutrients that will allow them to germinate and someday grow into a wish-granting dandelion. Seeds come in all shapes and sizes and therefore require a range of different dispersal mechanisms. Water is another natural force that plants can use to disperse their seeds.

Starting point is 00:18:20 One of the most well-known water travelers is typically thought of as a container for pina coladas, adorned with tiny umbrellas. Unlike the petite dandelion seed, a typical coconut weighs in at around three pounds, making dispersal via air an unlikely option for this hefty one-seeded droop. As beach dwellers, palm trees have evolved seeds that are dispersed via water. When the coconuts that contain palm seeds mature, they fall from the tops of the trees into the welcoming waves of the ocean. The coconuts then bob through the salty sea. This is possible thanks to a number of characteristics that the coconut has evolved. Its spongy outer covering makes it waterproof, which keeps the seed inside safe during its journey.

Starting point is 00:19:49 Coconuts are also able to float. If you've ever cracked open a coconut to get to the tasty flesh, you've probably noticed that there is a lot of empty space inside. This internal air cavity is what keeps the coconut to float during its journey. Their buoyant nature keeps them from sinking to the ocean floor, where they will have no chance of survival. On their quest for a suitable spot to sprout and grow into towering palm trees, coconuts may float in the ocean for over a hundred days. float in the ocean for over a hundred days. During this time, they can travel more than 4,000 miles.

Starting point is 00:21:01 This is roughly the same distance between New York City and the North Pole. If you were to go on a 4,000 mile road trip, you'd probably want to bring some snacks with you, and coconuts are no different. The coconut flesh that you've seen sprinkled on desserts, and the coconut water that you may have sipped on for some extra hydration, are adaptations that assist with seed dispersal. The coconut's embryo is nourished by this built-in food and water storage, making its impressive trip across oceans possible. Until the coconut finds land and can put down roots to get water and sprout leaves to obtain nutrients through photosynthesis,

Starting point is 00:22:07 it will be kept alive by the flesh and water inside the seed cavity. Eventually, the adventurous coconut's journey must end. The adventurous coconut's journey must end. Once it's washed up on the shore of a sandy beach, it will be ready to take root and grow into a tall palm tree. The next time you are taking a dip in the ocean, try to imagine what it feels like to be a coconut. You are in no hurry and are carried effortlessly across cresting waves. You have plenty to eat and drink, and don't have to worry about arriving at your destination anytime soon. A sandy beach that you will eventually call home awaits you. But for now, you can just enjoy bobbing through the ocean and go wherever the waves take you.

Starting point is 00:23:41 When your fingers become as wrinkled as prunes, and you decide to dry off and enjoy some time lounging on the beach. Take a moment to appreciate the large, round coconuts nestled high up in the leaves of a majestic palm tree. in the leaves of a majestic palm tree. As you enjoy the bit of shade offered by the wide palm fronds, think of the natural world in order to disperse their seeds, many other plants get a little help from animals. The tiny insects that are most commonly known for ruining picnics also lend a hand in the dispersal of seeds for certain plant

Starting point is 00:24:57 species. Wild ginger plants are an example of a plant species that are dispersed by ants. This plant resides on the floor of ants. While the wind and water require nothing in return, animal seed dispersers must be lured to complete their tasks with some kind of reward. This makes the relationship between the plant and animal mutualistic, meaning each party benefits. To encourage seed dispersal by ants, a fleshy structure known as an eleosome is secured to the outside of wild ginger plants. Eleosomes are full of fat and protein and are an attractive food source to ants. Wild ginger plants grow low to the ground.

Starting point is 00:26:34 The fruits that house their seeds dangle low enough to the forest floor that ants are able to easily sniff out the oily eleosome and snag the seed between their mandibles. Once they've got a secure grip on the seed, they carry it off to their nest to share with the other members of their colony. to share with the other members of their colony. When the seed reaches the ants' nest, the insects tear off the fatty eleosome. They are not interested in the seed itself. The unappetizing nature of it saves it from being chewed up by the ants. This is good news for the seed, because if it were to be torn apart by the strong mandibles of an ant,

Starting point is 00:27:44 it would no longer be viable for germination. Ants are very tidy creatures and don't like to leave their refuse lying around their nest. After they've pulled off the eleosome, they get to work disposing of the seed. The ants once again hoist and secure the seed between their mandibles and carry it off to a rubbish heap where they dispose of other unwanted materials. These rubbish heaps are actually very rich in nutrients, and are a fertile spot for a seed to germinate and grow. Unlike dandelions and coconuts that are dispersed miles away from their parent plants, wild ginger seeds are typically only carried a few feet away. However, this short distance is just far enough to prevent competition between the parent plant and the offspring

Starting point is 00:29:07 that will germinate from the dispersed seed. Despite the short distance that the seed will This is still an impressive feat for a tiny ant and a small, sedentary plant. These insects are known for their surprising strength. In spite of their small stature, they are able to carry seeds that are up to 20 times heavier than their own body weight. If a human were as strong as an ant, they'd be able to lift up to 4,000 pounds. The incredible strength of ants and the presence of allozooms on wild ginger seeds make for an amazing mutualistic relationship that benefits both the insect and the plant. Ants are just one of the living creatures that help spread seeds. Squirrels are one of the most well-known and prolific seed dispersal agents. Without their help, many tree species would be unable to spread their seeds,

Starting point is 00:30:48 and forests as we know them would not exist. However, the relationship between plants and these fluffy-tailed rodents is not purely mutualistic. As seed-eating animals, squirrels are both harmed and helped by squirrels. Oak seeds are encased in a tough outer shell known as an acorn. When the seed is mature, the acorn will be dropped to the forest floor, where squirrels forage for food. Once a squirrel gets a hold of an acorn, it will be met with one of two fates. If the acorn is unlucky enough to be found by a squirrel that's in search of a quick snack, the animal will use its strong teeth to break through the shell

Starting point is 00:32:16 and eat the seed. When this happens, the squirrel is considered a seed predator because the oak seed will be destroyed and will lose all hope of growing into a towering oak tree. A squirrel that eats an acorn is an enemy of an oak tree. However, squirrels may also inadvertently serve as a friend to an oak tree by helping to disperse its seeds. If an acorn is lucky, it will be found by a squirrel that is planning ahead for the winter months when food sources are scarce. The animal will tuck the acorn into a special pocket inside its mouth and scurry away with bulging cheeks. The acorn will then be buried in a shallow hole in the forest floor, known as a cache. The squirrel will plan to revisit the cache to dig up their snack in a few months when

Starting point is 00:33:49 food sources are much harder to come by. At this point, there is still a chance that the acorn will be destroyed by the gnawing teeth of the animal that chose to bury it and save it for later. Squirrels have impressive memories and are often able to return to the exact spot where the cache was created and use their paws to dig up the acorn. However, many of these buried acorns will escape predation and be given the chance to germinate and grow into an oak tree. into an oak tree. There are a number of reasons why a squirrel may not return to the cache to fetch their seed. They may have squirreled away more food than they need to get themselves through the winter and will decide not to dig up the buried acorn. These rodents are very busy and spend the autumn months stocking up their winter pantries. A squirrel can hide up to 10,000 nuts every year, and only recover an average of 74% of

Starting point is 00:35:32 the food that they hide. Considering the large amount of acorns that get buried each autumn. It's no wonder that a large portion of them escape predation. Some caches containing acorns are abandoned in favor of food that is more easily accessible. of food that is more easily accessible. However, it's believed that squirrels' memories are not entirely perfect and that they may simply forget where some buried their cash, the acorn is saved. The ones that are lucky enough to make it through the winter will have a chance to germinate and grow into a tree that will one day produce acorns of its own. Squirrels that are forgetful or not in need of the food in their cache serve as dispersal agents for oak trees. trees. As you can see, this is not your typical tit-for-tat mutualistic relationship. These are just a few examples of ways in which plants send their seeds out into the world in search of a suitable environment

Starting point is 00:37:29 to call home. Even though plants must play a passive role in deciding where their offspring end up, they've still evolved a wide range of seed features that aid in this process. When these mechanisms that the plants have evolved are successful, their seeds will end up in a place where they can germinate, grow, and produce their own seeds. Next time you're rambling through the forest, lounging on the beach, or blowing on a dandelion, think about how each plant ended up where it did, and say a quiet thank you to the animals, the wind, and the water that lent a helping hand in getting them there. The You You You You You The You You I'm going to go ahead and close the video. You You You You You You You. you

Get Sleepy: Sleep meditation and stories - The Sleepy Science of Seed Dispersal

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