If us humans seperate gas from air and the fish gills will seperate water from air.why cant they breath on the surface. they have gills we have lungs
2006-11-23 00:42:39 · 8 answers · asked by Dianna_jone 1 in Science & Mathematics ➔ Zoology
omg! thats like stupid.. really.. go to school & learn something
2006-11-23 00:44:36 · answer #1 · answered by Claude 6 · 0⤊ 0⤋
The air is NOT a chemical compound of gases. It is simply a mixture. Our lungs have the capacity to extract oxygen from this compound and transfer it into our blood. (This goes wrong when there's to much carbon monoxide in the air as it clings onto the haemoglobin more easily than the oxygen, producing carboxyhaemoglobin which the body cannot use.) Our lungs don't have the capacity to split the chemical compound of water into hydrogen and oxygen. The fish's gills can. For the opposite reason fish can't breath on the surface.
2006-11-23 08:49:07 · answer #2 · answered by f+v=e+2 Euler's a genius!!! 1 · 0⤊ 0⤋
It is the dissolved oxygen in water that the fish, crustacia, and other aquatic creatures breathe. They have gills (and the body surface in some earlier creatures) that can separate oxygen from water, which is a liquid. Now the molecules of a liquid are closely packed than the gases, so the aquatic animals can get enogh oxygen from water even though (compared to air) very little oxygen is dissolved in water. In air, or any gaseous mixture the molecules are much too far apart and enough oxygen molecules would not touch the gills or the body parts of fish. Hence they suffocate on land. Land creatures have developed special capacity during evlution to exchange oxygen and carbon dioxide directly from gases or air. This requires comparatively very high proportions of oxygen (in parts per hundred) as compared to liquid or water (in 10X to 100X parts per million)
2006-11-23 10:03:19 · answer #3 · answered by tavker_elec_it 2 · 0⤊ 0⤋
Gills are designed only whilst water is passing through them. It's the water that causes the exchange of water. that's why some fish and crustaceans are able to go under a certain type of stasis by being in just a very small amount of water. they are effectively breathing air, but water still surrounds their gills.
Our aveoli are not capable of seperating the air out of the water. For a start, we couldn't do it quick enough without continuous water flow (which is why big fish and sharks must constantly swim in order to survive). Water simply doesn't hold the same percentage of oxygen per square metre that air holds.
2006-11-23 08:50:03 · answer #4 · answered by moentran_au 1 · 0⤊ 0⤋
You sort of answered your own question. We have lungs, not gills. Lungs separate oxygen from the air, and gills separate oxygen from the water.
2006-11-23 22:33:27 · answer #5 · answered by Anonymous · 0⤊ 0⤋
you c our lungs can't hold a lot of pressure in the water so we need to surface where the fishes gills are designed for water yet not land , if a fish is out of water if it is not placed back in i=it's organs dry out causing it to die
2006-11-25 17:38:34 · answer #6 · answered by blue-bird 2 · 0⤊ 0⤋
lack of gills... and its oxygen... we remove oxygen from gases that make up our air... but fish have water flow over their gills... we start out able to breathe in water...
2006-11-23 08:45:01 · answer #7 · answered by israeli_stuck_in_usa 3 · 0⤊ 0⤋
Our lungs only accept oxygen not water
2006-11-23 21:17:00 · answer #8 · answered by sam 3 · 0⤊ 0⤋