http://www.newsoxy.com/science/jawless-ancient-fish-162855.html
are these ancestral to jawed sharks?
are these ancestral to jawed sharks?
Primitive jawless fish found
- Thread starter Walter L. Wagner
- Start date
Fraggle Rocker
Staff member
I can't find enough information. Judging from its age, it could be an ancestor of all the cartilaginous fishes (sharks, rays, eels, etc.). This would make it an ancestor of all chordates, including cartilaginous fish and vertebrates (bony fish, amphibians, reptiles, birds and mammals).
However, it could also be merely one species of jawless fish which may or may not have been in the evolutionary line that resulted in the modern chordates. And for that matter, it may or may not have been in the evolutionary line that resulted in sharks.
In reply to AIP's, re: jawless fish.
Nature seems to use the same "patterns" regarding "form follows function", as in "if it ain't broke, don't fix it" philosophy.
(as a side-issue, there seems to still be debate involved with sharks regarding the "Great White", as in "Is this a true shark?" The "zona miracula" feature seems to defy
explanation, the ability of this creature to "warm it's own blood", thus making it part of the endotherm family! Definitely not a "usual" shark feature)
(Thanks for reading!)
Nature seems to use the same "patterns" regarding "form follows function", as in "if it ain't broke, don't fix it" philosophy.
(as a side-issue, there seems to still be debate involved with sharks regarding the "Great White", as in "Is this a true shark?" The "zona miracula" feature seems to defy
explanation, the ability of this creature to "warm it's own blood", thus making it part of the endotherm family! Definitely not a "usual" shark feature)
(Thanks for reading!)
It is a rather amazing fact that a great whites body temperature is a few degrees above the surrounding water, but not unprecedented. The Blue Fin Tuna also has a body temperature that is above the surrounding water. I would think that a great white is clearly a shark however it also appears to be a unique shark.
What is "zona miracula"?
Fraggle Rocker
Staff member
I can't find it. Obviously it's modern scholarly Greco-Latin, meaning "zone of miracles," "miraculous zone," or something like that. But it's not in any of the sources where I look for words.
Fraggle Rocker
Linguistics Moderator
In reply to Fraggle Rocker, re: your #5 post.
You have it correct..."miracle zone". It is one of those "catch-all" phrases, much like "fundus" can be used to describe an area of the body that may have an empty region, such
as "gas in the fundus of the stomach" or a Eustachian tube. (I think you may find it some of the older medical terminology books)
The scientist who worked on the research of the sharks' ability to increase the metabolism of it's "swimming" musculature, thus enabling it to swim and follow prey at high
speeds for hours had an Italian surname...I remember he was a Phd. but I can't remember the name.
.....
An interesting side issue.
I watched a "Nature' program about 3 yrs. ago (a shark week thing) and heard something remarkable. A young female "White" was "tagged" with a transponder off of the
African coast (maybe Australia?) and the results of much of the "burst" transmissions were shocking...this tagged female traversed the entire Pacific Ocean to the Americas!
Not only did she swim at steady pace covering thousands of miles...in many instances, she was at depths exceeding a mile! For hours at a time! Why?
It's damn cold at that depth, and nothing tasty to eat...was she "conserving" caloric energy somehow by swimming at great depths? Or maybe killing off her parasites?
These two things are my "best guess"...I don't think there was any "specialized" hunting occurring.
(I also think she was running on "auto-pilot" and using the relatively low oxygen density to "slow" her cellular metabolism...but this is speculation)
(Thanks for reading!)
You have it correct..."miracle zone". It is one of those "catch-all" phrases, much like "fundus" can be used to describe an area of the body that may have an empty region, such
as "gas in the fundus of the stomach" or a Eustachian tube. (I think you may find it some of the older medical terminology books)
The scientist who worked on the research of the sharks' ability to increase the metabolism of it's "swimming" musculature, thus enabling it to swim and follow prey at high
speeds for hours had an Italian surname...I remember he was a Phd. but I can't remember the name.
.....
An interesting side issue.
I watched a "Nature' program about 3 yrs. ago (a shark week thing) and heard something remarkable. A young female "White" was "tagged" with a transponder off of the
African coast (maybe Australia?) and the results of much of the "burst" transmissions were shocking...this tagged female traversed the entire Pacific Ocean to the Americas!
Not only did she swim at steady pace covering thousands of miles...in many instances, she was at depths exceeding a mile! For hours at a time! Why?
It's damn cold at that depth, and nothing tasty to eat...was she "conserving" caloric energy somehow by swimming at great depths? Or maybe killing off her parasites?
These two things are my "best guess"...I don't think there was any "specialized" hunting occurring.
(I also think she was running on "auto-pilot" and using the relatively low oxygen density to "slow" her cellular metabolism...but this is speculation)
(Thanks for reading!)