why humans are unable to breathe underrwater the way marine animals do?

Question

why humans are unable to breathe underrwater the way marine animals do?

Answer 1

I assumed you meant marine mammals. They don't breathe underwater. They hold their breath.

As for fish and people. We aren't water dwellers. They are land dwellers. To each their own.

Answer 2

Marine mammals cannot breathe under water, they have lungs just like most land animals. Fish, sharks and other aquatic species have a variety of ways to extract the oxygen molecule from the H20 grouping. These organs range from gills, bladders, and other exotic and strange appendages.

Humans, marine mammals and other land species who have lungs are only able to absorb oxygen in it's relatively pure form. We do not have any way of separating oxygen molecules from other chemicals until that oxygen is in our blood stream. So we cannot breath underwater because the oxygen molecule is essentially unavailable to our bodies.

Answer 3

Our lings are adapted to a higher rate of gas exchange than water can provide.

Which is to say, we can't pull enough oxygen out of water to feed our metabolic fire, and we can't push enough carbon dioxide into it to keep the CO2 from extinguishing us.

Most true marine animals have much lower metabolic rates than us, so they don't need to get as much oxygen from the water or need to expel as much CO2.

Those that push the boundaries of marine metabolism have more aggressive means of pushing water through their breathing apparatuses i.e. bigger gills in relation to body size or gaping mouths and nonstop swimming.

The modified swim bladders that have become our lungs were never really used as more than an augmentation to gills by transitional fish/amphibians.

They evolved to deal with air and can't use old fashioned h2o. The atmosphere was more oxygen rich when the first terapods waddled away from the shores to look around, so lungs didn't need to be very efficient initially.

They've never had to close what would be a huge gap in the ammount of volume of water needed to flow through them to get as much gas exchange as they get from air.

Our air passages and lungs aren't really suited to that, we'd have to reactivate the genes that control gill formation and shut off the genes that cause the gill arches we develop as embrios to be reabsorbed.

Course, then we'd need to swim around with our mouths open which would be sort of yucky, but it'd be poetic justice, as we're responsible for a good portion of the funk.

Answer 4

Marine mammals don't breathe under water any more than we can! They have a metabolism that can use much lower levels of oxygen for longer periods than we can. They still have to surface in order to breathe. Jules, lecturer. Australia.

Answer 5

Coz the have gills which help them take in the oxygen dissolved in water..n lungs r nt able to do tht n need oxygen in gaseous state..
I have two suggestions for you
1)Don't post such questions n make a fool out of urself..
20)Get real ...pay attention in class..if u r nt a dropout...n plzz give ur brain sum exercise..

Answer 6

As i have been studying Humanity as close as is accessible -- in a vessel -- i am going to offer them this a lot: The complexity of Human questioning is superb sufficient, that the occasional mistake is inevitable. it really is balanced out by the feats of intelligence the species can do on good days.  

Answer 7

Marine MAMMALS do NOT breath underwater, like humans they must surface periodically for air.

Answer 8

You can ! It takes practise. Tie some lead weights to your body and jump into the deepest part of the river. In about an hour you will be beathing water and not air.

Answer 9

cause we don't have gills...why can't marine animals breath out of the water? same reason

Answer 10

humans breath the oxygen in the air they cannot inhale the oxygen present in water since it the limitation of humans.