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Previous poll results: Where do you get your textbooks?
  
wrote...
Posts: 12
Rep: 1 0
4 years ago
Hi Dear Biologists.
I have this question that I wrote in subject.
I searched about it in websites and find 2 these links:

http://dsc.discovery.com/tv-shows/shark-week/about-this-show/can-sharks-drown.htm

and

http://www.sharky-jones.com/Sharkyjones/Slow/QandA/QA7%20-%20swimming.html

which one in true according scientific discovers? also if second link is true can you introduce and old book o article about it (e.g a book or article from before of 2000)? [request of book in urgent]

*sorry if I sent my topic in a wrong forum Wink Face
Thanks a lot.
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16 Replies
wrote...
Staff Member
Educator
4 years ago
It's never any good to make generalizations like that, especially as a biologist.

Like other fish, sharks "breathe" through their gills, which are respiratory organs akin to our lungs. As water passes over the gill's membranes, tiny blood vessels extract oxygen from the water. Carbon dioxide waste also passes from the shark's blood and out of its body through the gill tissue.

But just how the sharks force water over their gills differs among species.

Some sharks, particularly those that are not active swimmers, such as nurse and bullhead sharks, breathe using buccal pumping. This method gets its name from the buccal (mouth) muscles that actively draw water into the mouth and over the gills, allowing the sharks to respire while remaining still.

These sharks also have prominent spiracles, or respiratory openings behind the eyes that allow the fish to pull in water while buried under sand.

Other sharks use ram ventilation; that is, they ventilate their gills by swimming very fast with their mouths open. Some sharks, such as the tiger shark, can switch between buccal pumping and ram ventilation depending on quickly they're swimming.

"Obligate ram ventilators" are sharks that have lost the ability, and the necessary anatomy, for buccal pumping, and instead can only respire using ram ventilation. Sharks from this group (which includes great white, mako and whale sharks) would indeed die from lack of oxygen if they stopped swimming.

In terms of a finding a research article, use the Free Pubmed search to your right.
Mastering in Nutritional Biology
Tralalalala Slight Smile
wrote...
4 years ago
first thanks for your attention.
 - I'm 1 year student of biology and I have not enough information about that. Frowning Face
 - in first link I read this text but are you sure the high weight of them is not the reason? because I read in site that they have not swim bladder and it's the reason of swimming always that described in second link. 

 and no any book about that?
wrote...
Staff Member
Educator
4 years ago
- in first link I read this text but are you sure the high weight of them is not the reason?

I can see that as being a contributing factor, but now the main reason since they are ram ventilators. The more they move, the more they are exposed to water. In addition, unlike bony fish, sharks do not have gas-filled swim bladders for buoyancy. Unfortunately, I don't have any other resources to back this up Undecided

Mastering in Nutritional Biology
Tralalalala Slight Smile
wrote...
4 years ago
However thanks!
...
I see this theory in Wikipedia about sharks swimming!
"Dynamic lift"
http://en.wikipedia.org/wiki/Dynamic_lift_(fish)#Dynamic_lift

do anyone know who said this theory and when this reason found? :/
wrote...
Staff Member
Educator
4 years ago
No, sorry Frowning Face

But I added an attachment
Mastering in Nutritional Biology
Tralalalala Slight Smile
wrote...
4 years ago
Thanks a lot Padre for sharing this useful file Wink Face

another question.
did anyone read this book?
"Biology of Fishes" by "Q. Bone, N. B. Marshall, J. H. S. Blaxter"

I have not this book and cannot access to it but I read index of it in a site and it had a part as "dynamic lift" . did anyone read it? this text about same way that sharks and many fishes use it?
can anyone share ebook of it? :/
wrote...
Donated
4 years ago
Hey, this is what the book contains about dynamic drift, see attachments
Attached file(s)
Thumbnail(s):
wrote...
Staff Member
Educator
4 years ago
no, sorry

thx mikael
Mastering in Nutritional Biology
Tralalalala Slight Smile
wrote...
4 years ago
Thanks a lot Dear friends. Slight Smile
as latest question in this topic, which is the edition of the book? Slight Smile
wrote...
Donated
4 years ago
Thanks a lot Dear friends. Slight Smile
as latest question in this topic, which is the edition of the book? Slight Smile

good question, does "Biology of Fishes" have any editions?
wrote...
4 years ago
have not? :/
first edition 1982 - second edition 1995 - and maybe third edition! :/
wrote...
Donated
4 years ago
It is the one published in 2004, the title page looks like this, page 314

wrote...
4 years ago
but in this page http://link.springer.com/book/10.1007/978-1-4615-2664-3/page/1  and in front matter file ( http://link.springer.com/content/pdf/bfm%3A978-1-4615-2664-3%2F1.pdf ) they wrote first edition is from 1982 and second for 1995? :-/
        
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