YouTube: https://youtube.com/watch?v=9VdharmslWc
Previous: That Time the US Government Poisoned Alcohol
Next: 5 Times Scientists Gave Animals Drugs (and What They Learned)

Categories

Statistics

View count:1,082
Likes:144
Dislikes:1
Comments:20
Duration:05:52
Uploaded:2018-11-09
Last sync:2018-11-09 17:10
Corals might have a fighting chance against bleaching, and fuzzy moths aren't just sporting their fur because it's adorable.

Hosted by: Hank Green

SciShow has a spinoff podcast! It's called SciShow Tangents. Check it out at https://www.scishowtangents.org
----------
Support SciShow by becoming a patron on Patreon: https://www.patreon.com/scishow
----------
Dooblydoo thanks go to the following Patreon supporters: rokoko, Alex Hackman, Andrew Finley Brenan, Lazarus G, Sam Lutfi, D.A. Noe, الخليفي سلطان, Piya Shedden, KatieMarie Magnone, Scott Satovsky Jr, Charles Southerland, Patrick D. Ashmore, charles george, Kevin Bealer, Chris Peters
----------
Looking for SciShow elsewhere on the internet?
Facebook: http://www.facebook.com/scishow
Twitter: http://www.twitter.com/scishow
Tumblr: http://scishow.tumblr.com
Instagram: http://instagram.com/thescishow
----------
Sources:

Corals:
https://genomebiology.biomedcentral.com/articles/10.1186/s13059-018-1552-8
http://www.pnas.org/content/115/20/5235.short
https://www.scientificamerican.com/article/scientists-are-taking-extreme-steps-to-help-corals-survive/
https://www.sciencedirect.com/science/article/pii/S1687428513001118

Moths:
https://www.eurekalert.org/emb_releases/2018-11/asoa-msb110118.php
https://research-information.bristol.ac.uk/en/persons/thomas-r-neil(8ebdb0d9-f54a-4d32-b4f4-6c8325ce07da).html

Images:

https://commons.wikimedia.org/wiki/File:Colpophyllia_natans_(Boulder_Brain_Coral)_entire_colony.jpg
https://commons.wikimedia.org/wiki/File:Hertshoon.jpg
https://pixabay.com/en/moth-fur-coat-macro-portrait-3389449/
https://commons.wikimedia.org/wiki/File:Bat_echolocation.jpg
https://commons.wikimedia.org/wiki/File:Moth_01_(MK).jpg
https://commons.wikimedia.org/wiki/File:GrosPlanTetePaonNuit.jpg
https://commons.wikimedia.org/wiki/File:Brain_Coral_(Platygyra_lamellina)_(8485542235).jpg
[♪ INTRO].

Corals often pop up in the news and, usually not for good reasons. Especially if the word “bleaching” is also in the headline.

But there might finally be some good news for corals on the horizon. A study published last week in the journal Genome Biology suggests that some corals have the ability to make a nutrient most animals can’t, and that could mean they’re more resistant to bleaching. The goal of the paper was actually to find differences between two big groups of corals:.

Robust corals like the brain or mushroom varieties, and complex corals, which include big, branching types like staghorn coral. But, when the researchers compared the genomes of four complex species and two robust species with those of closely related sea anemones, they found something even more exciting. Hidden in the robust coral DNA was a recipe for making histidine, an essential amino acid.

Amino acids are the building blocks for proteins, the molecules that make up most of a cell’s machinery and act as structural support for tissues. Animals can make certain amino acids by themselves, but certain ones, called essential amino acids, have to come from their diet. Or, in the case of corals, from their special relationship with algae.

See, most reef-building corals have algae called zooxanthellae in their tissues that provide them with oxygen, sugars, and amino acids. The coral, in turn, gives its algae the starting materials it needs to make those things, like carbon dioxide, as well as a nice, protective home. But like all relationships, things can sometimes get a little rocky.

If conditions get too physically stressful, like if the surrounding water gets too warm or polluted, the corals evict their algal partners. This is referred to as coral bleaching because the algae give corals their color, so when they’re gone, the corals look bleached. Now, bleaching doesn’t immediately kill coral.

Sometimes, they recover and bring in new algal tenants. So being able to make histidine, instead of having to get it from algae, could help robust corals cope with stress, as it might let them last a little longer without their algae friends. Now, other animals generally can’t make histidine, but algae, fungi and bacteria all can, so the researchers wondered if the corals got the genes from one of them through horizontal gene transfer.

But the histidine-making genes were scattered all throughout the coral’s DNA and were broken up by non-coding sections, which means the corals probably evolved the ability to make histidine on their own very early on. The complex species of coral then lost the ability pretty soon after. Scientists also found that stress-tolerant corals had larger numbers of a particular gene called HSP20.

HSPs, or heat shock proteins, are found in many organisms and help protect cells from damage. So these might explain the corals’ increased stress tolerance, but the authors caution that this can’t be determined from genetic data alone. Still, these findings could help scientists select tougher corals when trying to restore reefs.

And they may suggest helpful ways to genetically engineer corals to withstand the warmer, more acidic oceans we’re getting thanks to climate change. In other survival-related news, biologists have discovered that the fuzziness of certain moths may be a strategy to hide from predators, specifically, bats. The bats that hunt moths see their prey in the dark using echolocation, sending out high-pitched calls and listening to how those calls bounce back to zero in on their targets.

But in a talk at the Acoustical Society of America's 176th Meeting, held in Victoria,. Canada this month, researchers suggested that this moth’s fur can act as a kind of sound dampening device. Biologists call this acoustic camouflage.

I didn't know this was a thing but that's great! Basically, that fuzzy stuff, which is made of modified chitin scales, not true hairs, makes the moths less echoey, so it’s harder for the bats to find them. The researchers figured this out by comparing the sounds reflected by two species of moths to two butterfly species which aren’t normally bat food.

They used a technique called acoustic tomography. In it, researchers send out ultrasound, pulses of sound with frequencies above what we can hear, from a loudspeaker, then they measure the echoes that bounce back using a microphone. By doing this from hundreds of angles, they could use a computer to combine all of the echoes into, like, an image of the moth, kind of like a sonogram.

But when the scientists aimed ultrasounds at the moths, most of them weren’t reflected back. The furry moths absorbed up to 85 percent of the sound that hit them, compared to just 20 percent for the butterflies. This was largely because of the fur: when the researchers removed the moths’ bristles by gently brushing them with a paintbrush, their bodies reflected 38 percent more sound.

Not all moths are super furry, though, and there’s probably a reason for that. Some species have evolved ears that can hear a bat’s hunting calls, allowing them to flee from their attackers, so they have less need for sound-dampening fur. Discovering the acoustical qualities of moths could help with more than just understanding moth evolution and ecology, or just my curiosity about why moths are all fuzzy and cute.

The researchers hope their discovery can inspire new sound-dampening materials for headphones, homes, or studios like the one I’m standing in right now, so we don’t have to be like “Oh my god! Stop walking around!” Thanks for watching, and thanks especially to our President of Space, SR Foxley. We really appreciate your continued support, SR!

If you want to be a President of Space like SR, support us here at SciShow, or just learn more about becoming a member of our patron community, you’ll want to head on over to Patreon.com/SciShow. And if you want to stay up to date on all of the latest science news, be sure to tune in every Friday right here, or click that subscribe on button. [♪ INTRO].