Tardigrades: The Most Resilient Animals in the Universe – YouTube Dictation Transcript & Vocabulary

1.this episode was brought to you by Skillshare tardigrades are the most resilient animals in the universe and there's probably one within a stone's throw from you right now hi I'm Danielle and you're watching Animal Logic tardigrades are a phylum of micro animals that are found pretty much everywhere on the planet from the depths of the ocean to jungles to rivers to mud volcanoes there are over a thousand species of tardigrade distributed across three classes you tarde Greta hetero tardy Greta and me so tardy Greta the main difference between the first two you tardy Greta and hetero tardy Greta is that you tardy Greta have a single orifice for reproduction and digestion while hetero tardy Greta have separate ones the third class me so tardy Greta has only been described by a single specimen discovered in 1937 the specimen was lost in an earthquake and no others have been found it's possible that this class doesn't exist tardigrades were first discovered in 1773 and at the time were named water bears this is due to the fact that they are normally found in freshwater and their movements resemble the gait of a bear the name tardigrade means slow stepper which is in reference to their relatively slow movement speed tardigrades are literally microscopic depending on the species they range in size from point 1 to 1.5 millimeters in length their body has a head three segments with a pair of legs on each and a caudal segment a tail with another pair of legs their legs have no articulation and have four claws at the end made of chitin the same material that makes up a crab shell they use their front six legs to grab things to propel themselves forward their rear pair of legs is used to grab onto the floor while they use their other six legs to nab food idle tardigrades have a set amount of cells and every member of the same species will have exactly the same number of cells this is called util II and it mainly occurs in microscopic organisms baby tardigrades are born with a full number of cell and rather than undergo cell division they grow as their cells do tardigrades don't have any respiratory organs and instead are able to do a gas exchange throughout their whole body their mouth has stylus which are like sharp little teeth they use these to pierce plants and small invertebrates after which they feed on the leaked fluids most species of tardigrade have compound eye cups and their bodies are lined with little hairs that help them feel vibrations tardigrades do have anal ducts and some of them only do their business when they molt another act that they save for molting is laying eggs after the female molds and lays eggs the male will fertilize them this mating process can last for over an hour but tardigrades aren't famous for their sex lives they're famous for their ability to tolerate environments that would kill other animals in seconds this is primarily true for terrestrial tardigrades marine tardigrades aren't quite as resilient as their habitats are much more stable in the most extreme of conditions terrestrial tardigrades can mummify themselves into little shriveled glass tardies called tongues and in the state they can withstand a whole heck of a lot some species can survive at almost absolute zero negative 273 degrees Celsius on the hot side of things they can survive for extended periods of time in temperatures of over 150 degrees Celsius far past the boiling point of water they aren't able to live in these extreme temperatures forever the longer they stay the lower their chances of survival they can live several days at minus 200 degrees Celsius and up to 30 years at minus 20 degrees Celsius during these extremely cold situations they enter the States called cryo by OSIS in order to protect themselves from the expanding water inside their cells they release cryoprotectants which make the ice crystallize in a way that is less damaging to their cells tardigrades can take a lot more than temperature though some species are able to withstand pressures that are six times higher than those encountered at the bottom of the Mariana Trench which is about the same amount of pressure that we get to talk about bearded dragons on Animal Logic some species of tardigrade can survive inside a vacuum and have even survived in outer space where they're exposed to both a vacuum and solar radiation as they were in an experiment by the European Space Agency in 2007 even their DNA is resilience it can tolerate extreme amounts of radiation due to a protein called a damage suppressor that protects it the protein reduces x-ray damage by 40% tardigrades can tolerate a thousand times more radiation than most other animals if you received a dose of about five gradiation you would die a tardigrade however can withstand 5000 grey tardigrades can also survive air deprivation and will simply float around until they're in a spot where they can breathe again same goes for dehydration they can survive with just 3% of their water content shriveling up to just a third of their size similarly some species of tardigrade can go without eating for 30 years after which they dry out become dormant and then they can rehydrate eat something and carry on as if nothing had happened it is rare for a tardigrade to go 30 years without food but they fairly regularly will go for at least 5 years without eating people tend to call tardigrades extremophiles but they're not an extremist file is an animal usually a bacteria that has adapted to live in an extreme environment tardigrades are just really good at living wherever they want be at the Himalayas in the depths of the ocean or in your backyard tardigrades have survived five mass extinctions and unlike every other animal that we cover on this channel they're well equipped to survive the next one if you're interested in getting started in scientific illustrations a good starting point is with a course on Skillshare pen and ink scientific illustration taught by artist and educator patty Hsu will guide you through the process of illustrating an insect you'll learn how to add texture light and shadow to your images using hatching cross-hatching and humbling the corpse is great for beginners and the best part is that all you need to follow this course on Skillshare is a pen and paper Skillshare is an online learning community with over 20,000 courses and they offer a ton of other courses on illustration that you might want to check out if you're interested in building your skills as a scientific illustrator with steel chairs premium feature you'll have unlimited access to all of these courses so you can build your skills and join a passionate like-minded community of learners and artists if you want to support animal logic and learn something new on Skillshare follow the link in the description to sign up for two months of Skillshare for free what animal should we check out next please let me know in the comments and be sure to subscribe for new episodes of Animal Logic every week if you want to watch a time-lapse of the drawing from this episode make sure that you subscribe to our new channel Animal Logic by design thanks for watching [Music] [Music]