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On New Year's day, we said goodbye to George the Snail, marking the first extinction of 2019, and the way things are looking, it won't be the last.

Hosted by: Hank Green

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Sources:

George the snail:
https://www.theguardian.com/environment/2019/jan/08/george-the-snail-tree-snail-hawaiian-islands-biodiversity
https://www.nytimes.com/2019/01/10/science/snail-dead-george-species.html
https://www.researchgate.net/publication/315678140_Measuring_the_Sixth_Extinction_what_do_mollusks_tell_us
http://dlnr.hawaii.gov/blog/2019/01/04/nr19-001/

Antarctic animals:
https://www.frontiersin.org/articles/10.3389/fmars.2018.00507/full
https://www.scientificamerican.com/article/thinning-arctic-ice-allows-plankton-bloom/
[ INTRO ].

On New Year’s day, a tree snail called George died in a terrarium in Hawai’i at the ripe old age of 14. And while the death of a single snail might seem insignificant,.

George had been the last known Achatinella apexfulva for more than a decade. So that death marked the first extinction of 2019— and with the way things are going, it won’t be the last. George the snail spent its entire life being cared for by biologists, a fate now shared by dozens of its close cousins.

There were once over 700 species of land snail in Hawai’i, including hundreds of Hawaiian tree snails that, like George, feed on the fungi, algae and bacteria that grow on leaves. When British explorers first came to the islands in the 1700s, they described clusters of colorful snails hanging from the trees. But many of those are now gone, thanks to centuries of human harvesting and the introduction of the snail-eating rosy wolfsnail in the 1950s.

By the late ‘90s, scientists studying Hawaii’s native snails realized that dozens of species were on the brink of extinction, so they established a captive breeding program. And in 1997, the last ten or so wild snails of George’s species were all taken to the lab at the University of Hawai’i. Tree snails take 5 to 7 years to mature, and after mating, each pair of snails gives birth to less than ten babies annually.

So captive breeding was slow going, and then, in the early 2000s, most of them just… died. Only one juvenile survived— and it was nicknamed George, after Lonesome George the tortoise. Though researchers searched for over a decade, they never found another apexfulva.

So George’s death marked the end of an entire species. And if that’s not sad enough on its own, it’s just the latest of a string of extinctions —especially in snails and slugs. If you look at all the known extinctions that have occured since 1500, about 40% are land-dwelling mollusks.

Worldwide, scientists estimate more than 600 snails and slugs are now extinct because of habitat destruction, climate change, invasive species, and even tourism. And in 2017, scientists used the group to calculate the likely extinction rates for all animals over the next century and a half. And it doesn’t look good.

Their estimates suggest we could lose 5 percent of all species each decade, which means half of all the animals on Earth could go extinct in the next 150 years. As devastating as that is, such dire predictions assume that we stay on our current path. The biologists that worked with George have emphasized that there are lots of species we canstill save—including many of George’s cousins— if we turn things around sooner rather than later.

And... not all species are barreling towards extinction. A new paper in the journal Frontiers in Marine Science has found that some Antarctic species might actually benefit from climate change. They did a risk assessment analysis to estimate how dozens of species will likely fare in the next 50 years or so, depending on how fast the Antarctic warms.

The scientists first trawled through a ton of academic literature to come up with seven environmental factors that would most strongly affect Antarctic species —stuff like rising temperatures, ocean acidification, or melting sea ice. They then found research which could speak to how each factor would impact a given species. They then tallied these up for 31 Antarctic species.

The vast majority of the 21 invertebrates they studied—70 percent—would likely benefit from climate change. For example, less sea ice means more sunlit water where plant-like phytoplankton can grow, and that means more to eat for suspension feeders like clams and jellies. And as the ice breaks up, it tends to drift into shallower waters and scrape the seabed.

That’s good news for bottom feeders like the proboscis worm and cold-loving sea stars, which would be able to spread out and gobble up any organisms killed in the process. What was really surprising, though, was that about half of the 10 bony creatures studied may benefit a little, too —at least indirectly. The king penguin, for example, might have more room to breed because the receding ice opens up space on the glacial plains where it loves to nest.

And both the king penguin and the southern right whale might do better because their main food sources, small fish and crustaceans, feed on plankton blooms, and are therefore predicted to increase in numbers. But—and it’s a pretty big caveat—most of these animals will also lose a major source of food: krill. That could mean the end of species like adélie, emperor and chinstrap penguin s as well as humpback whales.

Also, even if an animal benefits in a big way in one category —like food availability— they might lose out in another, like having good habitat available. And scientists don’t yet have a totally clear understanding of how the environmental factors interact or influence one another. So, while a species might get more pluses than minuses in a risk assessment, they might not do so well in real life.

One thing is certain: a lot will change as the planet warms. The Antarctic ecosystems forged by climate change will look very different from what we see today. And I don’t know about you, but I’m kind of partial to the penguins.

Thanks for watching this episode of SciShow News! And a special thanks to our President of Space SR Foxley. You’re the best, SR!

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