Claire Corlett

Fish Food, Fish Tanks, and More
Why Fish Can Drink Salt Water And We Can’t

Why Fish Can Drink Salt Water And We Can’t

Salt is everywhere on our planet, but some
animals evolved to live in it while, others didn’t; what happened there? What caused this
split? Sup salty dogs, thanks for watching DNews,
I’m Trace. Water is everywhere and is one of the main reasons life was able to evolve
on Earth. It’s pretty great. Salt is also everywhere. Salt and water together, make
up most of the water on our planet and it’s a major component of the beginning of life
as we know it! Organisms need salt to survive. Salt draws
water out of cells in process called osmosis. Osmosis is the tendency of water to flow across
a membrane to balance salinity. Essentially, nature wants to make sure there’s a balanced
level of salt everywhere. This is why if you drink saltwater you can die of dehydration
— the water-salt balance gets out of whack and water gets pulled out of your cells. It’s
pretty serious. And yet, as boney fish moved from a salty
sea into freshwater (or sweetwater), they had to eat salts to maintain that salt-water
balance. They still do this today, urinating any excess salt — sometimes up to a third
of their body weight a day. We do this too, which is why we crave (and love) SALT. But
this brings us to the big question — if saltwater fish are drinking saltwater constantly, how
do they avoid dehydration due to osmosis?! Well, there are two answers. One comes built
in. The gills of some saltwater species, like the flatfish: turbot, have adapted to carry
more of a special enzyme called “gill Na+/K+ ATPase.” This allows their gills to leach
salt from their bodies back into the ocean. Without this adaptation they’d die because
of that high salinity. But, some species of eel, salmon, bass, and
flounder have adaptations that let them move between fresh and saltwater! Species which
can survive in a variety of salinities are referred to as euryhaline; some even actively
adapt their gills or their kidneys… There are a lot of species osmoregulating in a lot
of different ways. This is a great example of how evolution solves a problem along many
different paths, something scientists call convergent evolution! SO AWESOME. So, lemme give you a couple examples: anadromous
fish, are born in freshwater and live there for months before they make for saltwater.
In Atlantic Salmon, an enzyme called type 2 deiodinase is produced in response to the
longer daylight hours in spring. Puberty ain’t just weird for humans. This enzyme alters
the salmon’s gills, initiating osmoregulation so they can safely swim into salty water!
This is reversed when they return to rivers and streams to breed and start the process
with thier own lil’ salmons. And a 2013 study in Molecular & Cellular Proteomics,
detailed how a DIFFERENT adaptation evolved in tilapia. When placed into salted water
gradually, the researchers found tilapia gills adapted, producing a specialized protein called
NDRG1. This let the tilapia survive in a saline environment — as long as they had time to
slowly adapt. A lot fish evolution has happened in the last
400 million years. Fish have spread into pretty much every water-based environment on the
planet. After the Great Dying 250 million years ago which wiped out 95 percent of all
marine species, evolution had to figure out how to osmoregulate again. Through an assortment
of convergent evolutionary adaptations FRESHWATER fish repopulated the oceans — learning to
deal with the super-salty water. Eventually, they made it to land as well, when a fish
named eusthenopteron evolved into amphibians — and tetrapods — like you and me! Without
salt, and being able to regulate it, life as we know it wouldn’t exist. Evolution is the best.

100 comments on “Why Fish Can Drink Salt Water And We Can’t

  1. Adaptation not equal to evolution.
    Find the missing links before you talking about evolution, it literally became just a dogma like religion.

  2. moonlight is cold you liars moonlight is cold I want my science award the Moon emits it's own light and it's cold I CAN PROVE THIS come on Trace any of you that have a curious science mind give me a chance to debate any of your best scientists the Moon emits it's own cold light.

  3. Dnews Can you explain Salt therapy that some companies are offering they say that it is good for you and charge a hefty sum for it. Is it just a scam. or is it real.

  4. whenever i hear quotes on timelines from 10k years ago or longer, i roll my eyes. it is all speculation and mostly BS. like dinosaurs for example.. carbon date a bone without letting the dater know what it is and the date is within 100k years. tell them it's a dinosaur fossil and they immediately date it as millions of years. to assume we know the timeline of anything just demonstrates humanities blind faith in bullshit.

  5. What stops different species from breeding with each other for example dogs and cats rhinos and elephant or a human and mouse I've always wondered this

  6. can you do a video on how gills work? how do they extract and isolate oxygen from seawater? thank you for your kind attention

  7. Evolution is the best! I worship evolution. I think evolution is God. God is brilliant. He sent his son to die for us. He is the epitome of good. I love God

  8. I drank salt water, I am crying am i going to die!?!?!? i am so scared i only drank 3 swallow of it! i am so scared!

  9. Evolution is still a theory even if it's talked about as fact. While I do believe there is a small amount of evolution that exist there is no concrete evidence that proves it

  10. Funny how fish are already in the ocean full of salt but they still need some salt when being cooked.

  11. evolution. when asked about it they say millions of years. we aint have millions years of life spawn. evolution is so wrong. 0+0=1

  12. Actually, we CAN and should drink sea water! Isotonized of course and not in big quantities, but it contains a lot of nutrients to our cells and a lot of elements of the periodic table, also, it's very similar to our blood and it can heal alot of diseases/illnesses and end whith desnutrition!

  13. Can we stop talking as if evolution is a fact? I mean it's still just a theory, you could do a video like this without saying "it's how they evolved" lol

  14. Actually, newly spawn Atlantic salmon live in rivers not for "months", but for 2-3 years before migrating to the ocean or the nearby sea, sea trout stay for 2-4 years, etc. Fish grow slower and live longer than many think they do.

  15. I don't think I've ever watched a video on this channel that doesn't reference evolution a bunch of times…try to stick to the facts please. You don't need to bring up a theory to explain how fish work. And please don't talk about evolution like it's a fact.

  16. Great video, I have a question: How does whale sharks and manta rays breathe and filter plankton with their gills, and how do they swallow the plankton ?

  17. Nothing evolved .Water on the beggiing was not salty it was fresh water and slowly it bacame salty .Evolution is not a intelligent person to figure something and nothing we observe did not appeared on this planet by the chance without intelligence or creator .Animals and sea creatures simply adopted to changable conditions , not evolved .They like to abuse this word frequently . It is not observable science as any animal has never changed kind . Animals multiply according to their kind , the same with humans and this is observable science that can be presented everyday withouts myhts about magical millions and billions of years .If not believe me please give me one observable example for evolution change of kind . Historians still argue about facts from the second WORLD WAR and that was just over 70 years ago , no one knows what had happened even few thousands years ago never mind even single milion years . We have got great scientific theories, aaumptions but ultimately these are not FACTS. It is not evolution it is adoptation . Fish stays fish all day and all year long and it does not morph into anything else . It was fish right from the beggining so was the cat dog etc , please give me one observable example for evolution change of kind one example will be enough one observable example not allegded one …………..Please do not say that something happened millions of years ago but we can not see it today …please be serious

  18. Nah Evolution is Retarded , if it was the best then it would've gave us the ability of drinking Salt Water that would've solved a lot of problems

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