[Music] I admit it we've given you some disheartening news lately about the fate of some of the world's coolest animals like bees suffering from colony collapse disorder and North American bats dying in Epic numbers because of the deadly white nose syndrome well sorry but we've got one more modern Extinction risk that you should know about to round out our Trifecta of Doom the worldwide amphibian decline amphibians include frogs toads salamanders and cilian many of these species live their larva lives in water and their adult lives on land and they use their skin as a second respiratory system amphibians have been around for an estimated 350 million years surviving the many harsh changes that smoked so many other animal groups along the way but just over the last few decades they've suffered sudden and serious declines with nearly 170 species thought to have gone extinct today of the more than 7,000 known species of amphibians in the world an estimated onethird are now threatened with Extinction a recent study by the US Geological Survey found us amphibians are Vanishing from their habitat at an average of 3.7% each year meaning they'll be gone from half their current habitats in 20 years so what's messing with Kermit and Mr Toad and all their homies Well turns out modern world can be a tough place for these sensitive guys and addition to problems like pollution from pesticides heavy metals and acid rain as well as mounting habitat loss studies show that amphibians are steadily declining because of disease specifically the Infectious fatal kitri micosis which is caused by the Aquatic fungus known as BD we're still not totally sure where the fungus originated though researchers have detected BD preserved in specimens from African clawed frogs dating back to 1938 this was around the same time that these frogs were being shipped around the world for use oddly enough in pregnancy testing so one Theory believes that they are the source scien has recently sequenced the genomes of nearly 30 BD strains from around the world and in doing so realized the evolutionary history of the fungus is more complex than they originally thought so more research is needed before we have any concrete answers regarding its origin but BD is one bad bad dude in just the last three decades it's caused the infection of at least 350 species many of which are now extinct in what may be the greatest disease-caused biodiversity killer in recorded history it works by infecting the amphibian superficial skin layers that contain the protein keratin this leads to a thickening or hyper keratosis of the skin and increased sloughing or shedding of the skin an amphibian skin is one of its most vital organs it's thin and permeable and involved in hydration Thermo regulation and resp ation many species breathe at least partially through their skin the skin also absorbs vital electrolytes like sodium magnesium and potassium but when BD interferes with the absorption it can cause nutrient deficiencies that ultimately lead to death by Cardiac Arrest if the infection hasn't already made the animal so weak that it either starves to death or is eaten BD has been found on every continent but Antarctica which you know there are no amphibians there so scientists aren't sure how the fungus moves through an environment on its own but evidence shows that it gets a lot of inadvertent help from us humans mainly through the international amphibian trade for use as exotic pets or human consumption particularly frogs legs climate change may also be aiding in the spread of BD warming temperatures extended droughts and general changes in the timing and amount of precipitation will affect the life cycles of amphibians all over the world plus as temperatures warm many plant and animal species shift their ranges to higher elevations infected amphibians migrating to these new territories bring the fungus with them and infect new population so the world's amphibians are in crisis mode but like with the bad catastrophe there are at least some things that you can do to help stop the spread of the disease and slow their decline like cleaning your boots and gear with a bleach solution after mucking around in ponds and marshes and not using amphibians as bait if you're into fishing also definitely not releasing your little sister's pet frog into the wild if she gets bored with it do it for the NES thank you for watching this episode of saow and thanks to our Cameo from Craig Weezy waiter Benzene if you want to continue getting smarter with us here at s show you can go to youtube.com slideshow And subscribe [Music]