All Seasons

Season 1

  • S01E01 Meet the Microcosmos

    • June 24, 2019
    • YouTube

    Join us on the first episode of Journey to the Microcosmos as we take a dive into the tiny, unseen world that surrounds us! With music by Andrew Huang, footage from James Weiss, and narration by Hank Green, we hope to take you on a fascinating, reflective journey!

  • S01E02 How Microscopic Hunters Get Their Lunch

    • July 1, 2019
    • YouTube

    On this week's journey, we explore the ways things eat in the microcosmos, from Stentors filter feeding to Dileptus hunting down and absorbing its prey.

  • S01E03 Stentors: Single-Celled Giants

    • July 8, 2019
    • YouTube

    It's time to meet a single-celled organism that is bigger than a tardigrade! We'll learn how Stentors reproduce, why they look like trumpets, and why some of them are just SO BLUE!

  • S01E04 How Do Microorganisms Reproduce?

    • July 15, 2019
    • YouTube

    How do stentors make more stentors? Does Paramecium reproduce sexually or asexually? Find out on this week's journey as we explore the ways the microcosmos reproduce!

  • S01E05 Where Did Eukaryotic Cells Come From? - A Journey Into Endosymbiotic Theory

    • July 22, 2019
    • YouTube

    1.8 billion years ago, a cell ate another cell, but it didn't digest it, and without that happening, we would not exist. This week we explore the origins of eukaryotic cells and ask the question, "Are our cells more than ourselves?"

  • S01E06 Tardigrades: Chubby, Misunderstood, & Not Immortal

    • July 29, 2019
    • YouTube

    We know these cute little water bears can survive the vacuum of space but are they actually immortal? We'll explore that and other misconceptions about tardigrades in this week's journey!

  • S01E07 How Do Protozoa Get Around?

    • August 5, 2019
    • YouTube

    If you were a protozoan, how would you zoom zoom zoom all around the microcosmos? From false feet to microtubules, find out how these single-celled eukaryotes make their way through the universe.

  • S01E08 Diatoms: Tiny Factories You Can See From Space

    • August 12, 2019
    • YouTube

    We owe so much to diatoms! They help us make beer, paint, and kitty litter, and they're responsible for some of the air you're breathing right now!

  • S01E09 Mysterious Jiggly Crystals and Other Intracellular Structures

    • August 20, 2019
    • YouTube

    Let's journey deep into the cells themselves to take a look at some of the structures that keep cells alive and others that do... something... that we'll figure out someday... probably.

  • S01E10 How Do Colonies Help Microorganisms Survive?

    • August 26, 2019
    • YouTube

    In the microcosmos, it's dangerous to go alone. This week we go on a journey into colonies to find out why sticking together is such a great strategy!

  • S01E11 Death in the Microcosmos

    • September 2, 2019
    • YouTube

    Death is inevitable and mysterious, even in the microcosmos. Stentors, heliozoans, and yes, even tardigrades, experience death in many different ways.

  • S01E12 Euglenoids: Single-Celled Shapeshifters

    • September 9, 2019
    • YouTube

    Euglenoids have had a very, very long time to evolve, and that has led to the things they have evolved into being extremely diverse—so diverse that, combined with the varied shape-shifting abilities of its member species, euglenoids have proven challenging to both identify and classify.

  • S01E13 Hydra: Stretchy, Speedy, & Probably Immortal

    • September 16, 2019
    • YouTube

    The hydra of mythology may not be as far off from reality as you think! Let's take a journey to the mall to meet our tentacled, regenerating friends!

  • S01E14 Relax and Enjoy the View

    • September 23, 2019
    • YouTube

    This week, we're taking a bit of a break, but we thought you might also like one. So, today, let's all just sit and look at our lovely little friends while we take a breath and enjoy Andrew Huang's amazing music.

  • S01E15 Life Without Oxygen? Challenge Accepted

    • October 1, 2019
    • YouTube

    Slimy, a little smelly, maybe even a little gross, but to many organisms, the oxic-anoxic transition is a shifting chemical boundary that has created a challenge for life...a challenge it conquered.

  • S01E16 Rotifers: Charmingly Bizarre & Often Ignored

    • October 7, 2019
    • YouTube

    We also don't really know what rotifers are... but we'll try to tell you as much as we know!

  • S01E17 The Microscopic Circle of Life

    • October 14, 2019
    • YouTube

    Life is chemistry. From diatom to Diana, life is not a magical imbued trait, is a process of the physics of our universe. The precise and convoluted chemistry of life requires specific physical and chemical situations. And this planet has a dizzying variety of such circumstances that, over millions or even billions of years, living chemical systems have evolved to thrive in.

  • S01E18 Amoebas: Occasional Brain-Eaters

    • October 21, 2019
    • YouTube

    Yes, they might eat your brain, but there's a lot more to amoebas than that!

  • S01E19 The Colors of the Microcosmos

    • October 28, 2019
    • YouTube

    We see the colors of the microcosmos every single week, but let's stop and ask why our some microbes are bright green, while others are a golden brown.

  • S01E20 Eating, Hatching, and Crashing into the Moon: More About Tardigrades

    • November 4, 2019
    • YouTube

    This week, the microcosmos meet the cosmos as we explore even more fascinating things about our friend, the tardigrade. We'll discuss their weird weird mouths, how we take care of our tardigrades, and what's going to happen to those tardigrades that crashed into the moon.

  • S01E21 Are Microbes Good or Bad for Humans?

    • November 11, 2019
    • YouTube

    Where is the line between good and bad microorganisms and why do we seem to know so much more about the bad ones?

  • S01E22 Paramecium: The White Rat of Ciliates

    • November 18, 2019
    • YouTube

    These world travelers might be, well, almost everywhere, but there is a still a lot we don't know about the famous paramecium.

  • S01E23 Microorganisms Are Cleaning the Water You Drink

    • November 25, 2019
    • YouTube

    Microbes are used for everything from baking to brewing, but wastewater treatment is where they do some of their most important work.

  • S01E24 What Microscope Do We Use? (And Other Frequently Asked Questions)

    • December 3, 2019
    • YouTube
  • S01E25 What Humans and Stentors Have in Common

    • December 9, 2019
    • YouTube

    This week, we're diving back into the world of Stentors to find out what humans and Stentors have in common!

  • S01E26 Gastrotrichs: Four Day Old Grandmothers

    • December 16, 2019
    • YouTube

    These little hairy-bellied friends lead a very interesting life, albeit a short one.

  • S01E27 We Recorded Some Strange Goop. What Is It?

    • December 23, 2019
    • YouTube

    This week's journey comes to you unedited and in real-time as we explore a mysterious infection.

  • S01E28 What If All the Microbes Disappeared?

    • December 31, 2019
    • YouTube

    In a world without microbes, this channel wouldn't exist. But there are other, more important things that would stop existing as well, and today we're going to explore just what could survive a world without our little micro friends, and for how long.

  • S01E29 Desmids: The Symmetrical Algae That's Full of Crystals

    • January 6, 2020
    • YouTube
  • S01E30 Microbes Don’t Actually Look Like Anything

    • January 14, 2020
    • YouTube

Season 2

Season 3

Season 4

Season 5

Season 6

  • S06E01 Giant Microscopic Cannibals

    • March 28, 2022
    • YouTube

    Every experiment has to start somewhere. This one began with a container full of dying microbes, and the five cute, pink ciliates called blepharisma that James, our master of microscopes, accidentally turned into a group of cannibals.

  • S06E02 How Many Cells Are in a Microscopic Animal?

    • April 4, 2022
    • YouTube

    We’re starting this episode out with a question that we’re never going to have a good answer for: how many cells do animals have? How could we ever hope to count all those cells in each of those animals? And how could we even begin to assume that the amount of cells in one individual is going to be the same for all the other individuals?

  • S06E03 The Remarkable Mystery of Land Plants

    • April 11, 2022
    • YouTube

    Somewhere around 470 million years ago, something happened that shouldn’t have been particularly striking. An algae found its way onto land. This algae turned the lands of this earth green, altered the chemistry of our atmosphere, and created homes for future life. This algae would give rise to all of the land plants we know of today.

  • SPECIAL 0x10 A Microscopic Tour of Death | Compilation

    • April 18, 2022
    • YouTube

    As strange as the creatures of the microcosmos are, their lives still revolve around the same fundamentals that ours do. There’s food, reproduction, and death. Yes, even microbes, hardy as they can be, experience death. In some ways, they invented it.

  • S06E04 There's More Than Coral at the Coral Farm

    • April 25, 2022
    • YouTube

    When you’re in the business of hunting for microbes, sometimes you have to send some weird emails. That’s why James, our master of microscopes, sat down one day to send his own strange request to the people at Coralaxy, a coral farm in Germany.

  • S06E05 We Finally Found the Elusive Bristle Worm!

    • May 2, 2022
    • YouTube

    We’ve spent most of our journey through the microcosmos seeking out the organisms that are too small to see with just the human eye. The bacteria, the ciliates, the tardigrades. Part of what makes them so exciting to find is that they are so tiny. Every moment we spend with one of these organisms is a peek into something exceptional in our experience of the world, and it’s the result of how much work James, our master of microscopes, has put into hunting down as many microbes as he can.

  • S06E06 Putting Coral Under the Microscope

    • May 9, 2022
    • YouTube

    James, our master of microscopes, recently received a package from a coral farm in Germany. We’ve explored some of the microscopic creatures and bristle worms that were living and thriving in those packages in previous videos. But today we’re here to focus on the main event: the corals.

  • S06E07 How Brownian Motion Helped Prove the Existence of Atoms

    • May 16, 2022
    • YouTube

    We’re going to see a type of motion over and over again because it’s all over the microcosmos, found in and around many different types of organisms. And this kind of random motion may seem almost too trivial to discuss, but this motion that you see is a proof of something fundamental not just to life, but to existence itself. This movement… is proof… of atoms.

  • S06E08 How to Not Kill an Extremely Rare Microbe

    • May 23, 2022
    • YouTube

    For an activity that mostly involves sitting and staring, microscopy is a surprisingly high stakes task. On the other side of the lens are drops full of potential, a multitude of worlds to unravel and examine. But they’re also fragile worlds, easy to fracture and lose with just a tiny slip of the hand. The stakes only get higher when you’re dealing with an organism so rare that it’s only been reported a few times since it was first discovered in 1901.

  • S06E09 Mouthless Parasites That Make Their Home In Worm Guts

    • May 30, 2022
    • YouTube

    You’ve heard those worm horror stories, right? Stories of painful stomach cramps or diarrhea or nausea that eventually turns out to be caused by some worms that have taken up residence in someone’s intestines. It’s so terrifying and wild to think of something so much smaller than us causing so much havoc. But, what if worms had to worry about their own guts being taken over by a parasite?

  • SPECIAL 0x11 We Made A Store!

    • June 6, 2022
    • YouTube

    This isn't just a project that tells people about their world, we hope it’s also an invitation into that world. And we want to help more people start their own journeys, so they can explore the unseen world that surrounds them. Head to https://www.microcosmos.store to get your own Microcosmos Microscope, microscopy accessories, and other Microcosmos merchandise!

  • S06E10 Can This Baby Rotifer Escape Before It’s Eaten Alive?

    • June 13, 2022
    • YouTube

    This Loxodes magnus is large, so large that it was able to eat a rotifer, those funny animals we often see getting bullied by their single-celled neighbors. Except, that rotifer is moving. It’s alive, twisting and turning inside of the food vacuole it’s been stuffed into, and starting to fight back.

  • S06E11 The Moss Animals That Are Defined by Their Butts

    • June 27, 2022
    • YouTube

    At first glance, they seem a bit more like plants or a series of flowers with thin, elegant petals. But no, they are indeed an animal. One that has the dubious honor of being defined largely by its anus.

  • S06E12 Getting to the Root of Nitrogen Fixation

    • July 4, 2022
    • YouTube

    James, our master of microscopes, is not a farmer. He is, to put it simply, fascinated by microbes. And that may lead him to strange places and cause him to grow tanks full of weird things. But he is not a farmer.

  • S06E13 A Two-Headed Ciliate and Other Adorable, Dead, and Extinct Things

    • July 11, 2022
    • YouTube

    The theme of today's episode is pretty simple: things we never thought we’d be showing you, but here we are.

  • S06E14 The Aquatic Snails That Leave a Path of Destruction

    • July 18, 2022
    • YouTube

    It’s often said that one person’s trash is another person’s treasure. And surely there is no greater proof of that than the home of our master of microscopes, James. All along the windowsills and bookshelves are jars and tanks full of samples gathered from ponds, lakes, and oceans. And even his cabinets and drawers and bathroom hold stockpiles of what he’s found. There is just one problem though... the snails.

  • S06E15 These Squishy Dots Move So Fast You Might Miss Them

    • July 25, 2022
    • YouTube

    From our vantage point, as relatively large organisms, it can be easy to overlook the microcosmos, because it’s simply too small to see. It floats in front of our eyes at all times, and yet we cannot make out details until we turn to other tools.

  • SPECIAL 0x12 The Microscope Upgrades We've Made Along The Way | Compilation

    • August 1, 2022
    • YouTube

    This channel wouldn’t be what it is if it weren’t for one very key invention: the microscope. Everything we see, we see with the aid of light and lenses, expertly deployed by our master of microscopes, James. And if you’ve been on this journey from the beginning, or if you’ve ever gone back to revisit our earlier videos, you may have noticed that things have changed a bit around here.

  • S06E16 Our Tardigrades Got Stuck in a German Post Office

    • August 8, 2022
    • YouTube

    Tardigrades have been through a lot. They’ve been sent to the moon. They’ve had the moisture sapped out of them. At times, they’ve been in extreme heat. And at other times, they’ve had to contend with extreme cold. Well, today, we’ve got a new one for you. A harrowing journey for these tardigrades that have taken them through, what we assume, must be the worst thing that tardigrades have yet been subjected to. These poor, enduring tardigrades got stuck in postal security.

  • S06E17 These Walking Ciliates Are Frustrating

    • August 15, 2022
    • YouTube

    The ciliates we’re going to talk about today are kind of…frustrating. At this point in our journey, we’ve gotten used to the fact that the microcosmos is an indecipherable mess at times, filled with organisms that look like each other, and who have familial relationships that seem obvious but then turn out to be a figment of our own limited imaginations. And these ciliates are yet another entry in the long-standing saga of ever-changing taxonomies that define our understanding of microbial species. The plot twist is inevitable.

  • S06E18 Water Mites: Sticky Dancers with Crystal Poop

    • August 22, 2022
    • YouTube

    The microcosmos might seem like a safe place from a surprise spider attack, but it would be misleading to pretend that it’s completely free of spider-like sightings. Because even at this small scale, you could find yourself subject to an ambush of the arachnid sort.

  • S06E19 We Accidentally Grew Crystals

    • August 29, 2022
    • YouTube

    Usually on Journey to the Microcosmos, we spend our time looking at living organisms, things like insects, plants, and microbes that move and breathe and grow and die. But today, for these first few moments, these are the only living organisms we’ll be showing you, a montage of creatures whose bodies all share one very eye-catching trait: crystals.

  • SPECIAL 0x13 You Can Have Your Very Own Microcosmos Calendar!

    • September 1, 2022
    • YouTube

  • S06E20 Ghost Fleas: Tiny See Through Cyclopses

    • September 5, 2022
    • YouTube

    Depending on your love of horror stories or your belief in the supernatural, it might be easy to convince you that lakes are full of ghosts. That as you plunge deeper into these lakes’ depths, you’ll come across translucent bodies that come alive when nighttime sets in; with its limbs all packed close to the head, wrenching open and closed like scissors that propel our spectral friend in jarring motions.

  • S06E21 Bacteria That Only Want To Head North

    • September 12, 2022
    • YouTube

    When James first saw these bacteria, all he knew is that they came from a sample taken from a Portuguese beach. And on the slide, the bacteria were swimming in a stark line. And that gave James an idea. He took out his phone and opened up his compass app. Then he placed the phone on the microscope stage to see what direction the bacteria were swimming in. And he found that the bacteria were all swimming north.

  • SPECIAL 0x14 An Hour of Our Uncut Microscopic Footage

    • September 19, 2022
    • YouTube

  • S06E22 The Shared Doom of Microscopic Hitchhikers

    • September 26, 2022
    • YouTube

    Our oceans and lakes are filled with copepods, a myriad of small crustacean species that might float as plankton or infect other creatures1. And as they’re living in whatever manner best suits them, some copepods—like our friend here—become more than just their own creature. They become a surface, a place for someone else (or something else) to settle down upon.

  • S06E23 Kentrophoros: The Mouthless Ciliate With a Back Full of Snacks

    • October 3, 2022
    • YouTube

    This is kentrophoros, a ciliate that James—our master of microscopes—had been searching for, receiving samples from all over the world in the hopes of finding it gliding around. When you first look at it, it doesn’t seem particularly special. But there are two things that the kentrophoros is famous for. The first is its lack of a mouth. The second is its coat of bacteria.

  • S06E24 These Rotifers Glue Themselves Together

    • October 10, 2022
    • YouTube

    As animals, we owe a lot to the single-celled organisms that came before us. These are the organisms that laid the chemical groundwork for how we live, from the DNA and proteins within them to the molecules they released into the environment. There’s something humbling about looking at our hands or feet and imagining the mixture of cells within them, and realizing the lessons that keep those cells bound together physically and biologically are rooted in a very ancient study in cooperation.

  • S06E25 Why Are These Single-Celled Organisms So Large?

    • October 17, 2022
    • YouTube

    One day, James—our master of microscopes—was cleaning the marine tanks that some of his organisms live in when he noticed this creature. It was hard to miss given that it was visible to the naked eye, thanks to both its bright red color and large size.

  • S06E26 Sand Is Full of Life and Death

    • November 7, 2022
    • YouTube

    James, our master of microscopes, gets samples of sand from beaches all over the world to help in his quest to learn more about interstitial ciliates—the single-celled organisms that live in the watery pockets that exist between grains of sand on the beach. But today, we’re going to shift our focus and let those grains be the focus of our show. More specifically, we’re going to talk about sand.

  • S06E27 The 18th Century Tardigrade Debate

    • November 14, 2022
    • YouTube

    If you’ve ever wondered what it might take to upset a microscopist, just ask James—our master of microscopes—his feelings about tardigrade legs. Yes, tardigrade legs. Those chunky, wiggly limbs that move their owner through meals of moss and fields of debris. What could possibly be in question when it comes to tardigrade legs?

  • S06E28 Is the Mitochondria Always the Powerhouse of the Cell?

    • November 21, 2022
    • YouTube

    It’s fun to watch organisms eat in the microcosmos. There’s a whole range of methods to enjoy. And at the core of all this is a simple, universal need: energy, stored chemically as adenosine triphosphate—or ATP—that’s made from the breakdown of sugars and fats.

  • S06E29 This Extremely Rare Ciliate Has Only Been Seen Four Times

    • November 28, 2022
    • YouTube

    If you’ve been following James, our master of microscopes, on some of his other platforms, then you know what’s coming. You know that James has published his first academic paper, it's about this extraordinarily rare ciliate that you see now called Legendrea loyezae.

  • S06E30 How We Got The DNA From This Extremely Rare Ciliate

    • December 5, 2022
    • YouTube

    To study organisms at the genetic level, we need their DNA. Which means that we need to be able to wade through all the bits and pieces lying within their tiny bodies to pick out something even tinier—something we can’t just dig out with a shovel. So how does James manage to get the precious DNA from Legendrea loyezae and the other ciliates he’s interested in studying?

  • S06E31 A Microscopic Tour Through A Norwegian Fjord

    • December 12, 2022
    • YouTube

    Sometimes our journey through the microcosmos feels like an expedition, a voyage filled with deep dives into the masses of organisms basking under the glow of our microscope. So what does it mean when you don’t find anything. When you gather your samples and excitedly prepare them for the microscope, only to find a landscape lacking in the life you expected to find?

  • S06E32 What Do We Have in Common With the Undulating Peranema?

    • December 19, 2022
    • YouTube

    Watching this Peranema feels a bit like watching a cat waffling back and forth between whether or not it wants to take a nap. Sometimes the Peranema stretches, its body undulating into an elongated, indescribable geometry as its flagella twitch like whiskers. And then, sometimes, it curls up into a cozy circle, tucking one end into itself the way any feline friend you might know curls up around the perfect beam of sunshine.

  • S06E33 The Collotheca Doesn’t Mind Eating Its Own Babies

    • January 16, 2023
    • YouTube

    Imagine that this is the beginning of the last thing you’ll ever see, an empty landscape with thin lines scratched across it. But those lines suddenly sharpen and gather into a dense mass that spreads from the crown that sits atop a giant, studded with greens and yellows. A giant that is in search of one thing: food.

  • S06E34 The Indecisive Evolution of Gastrotrichs

    • January 23, 2023
    • YouTube

    The Gastrotrich has long been a personal favorite microbe of several members of the Journey to the Microcosmos crew. But while we were able to see a lot with the microscopes we had at the time, James—our master of microscopes—has made some significant upgrades since then and this means that we are now able to see gastrotrichs in a whole new light.

  • S06E35 How Electricity Brings Order To Chaos

    • January 30, 2023
    • YouTube

    Science is built on questions. So let’s start today with one: what do you think happens when you set off an electrical spark in the microcosmos?

  • S06E36 The Microcosmos Is Made of Star Stuff

    • February 6, 2023
    • YouTube

    If you’ve been with us on our journey for a while, you’ve probably heard us say the phrase “we don’t know” a lot. The microcosmos doesn’t guarantee answers, and we’ve often found ourselves looking at some unusual behavior or beautiful form that represents some fascinating, unresolved mystery.

  • S06E37 Your Mouth Is A Cave For Microbes

    • February 13, 2023
    • YouTube

    You may not want to think about it this way, but your mouth is really just one giant, wet cave for microbes. From the perspective of bacteria, your mouth is not a tool. It is a home. It is a place that provides shelter and food, but it is also a place that can pose many threats. And the interplay between our mouths and the microbes that take up residence within them ends up, inevitably, affecting our own health.

  • S06E38 Microscopic Space Travelers

    • February 20, 2023
    • YouTube

    This might not look like much. But every day, tiny little things like this are raining down on our planet. Each one is small, about a millimeter across. But over the course of a year, each individual piece that makes its way to Earth’s surface adds up to around 30,000 tons.

  • S06E39 These Microbes Wear Chain Mail Made From DNA

    • February 27, 2023
    • YouTube

    The microcosmos is not always a graceful space. Sometimes an organism just needs to get around the way it gets around, even if that means looking like a swimming elephant head with a truncated snout at one end and a rat tail at the other.

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