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Evolution of Snakehead fish - Comments

Richard Dawkins's Avatar Comment 1 by Richard Dawkins

I doubt that you'll get a very helpful answer with respect to snake-head fish in particular. But the question you raise is a very general one. Remember two things. First, transportation of founder populations across a geographical barrier can be an extremely rare and improbable event and still be evolutionarily significant: it only has to happen once, in millions of years. Second, in Cretaceous times India was very much closer to Africa (actually Madagascar and South Africa) than it is today. In the late Cretaceous, India and Madagascar formed part of the same land mass.

Richard

Fri, 19 Nov 2010 17:31:42 UTC | #549969

SaganTheCat's Avatar Comment 2 by SaganTheCat

Thank you Richard, I tried googling maps of cretaceous earth but not being sure if these can survive in salt water or not (considering they breathe air they seem to be hardy things) and was trying to come up with scenareos of how populations can become transported.

on the plus side my partner said she found the discussion interesting and I may well be able to persuade her to read up on evolution, TGSOE is on our bookcase so maybe I'll get her to pick it up!

Fri, 19 Nov 2010 17:49:10 UTC | #549988

crookedshoes's Avatar Comment 3 by crookedshoes

Daniel Clear, I would suggest reading The Ancestor's Tale BEFORE reading TGSOE. It is more like a narrative and "flows". TGSOE then follows up with a slam dunk of the evidence! The best one two for evolution ever!!!!

As for the transport issue it could be a quite novel thing. I always revert to island biogeography and "first" inhabitants of island.... How'd the finches get to Galapagos? Then consider the Mexican Blind Cave Fish... It seems there has to be a logical pathway, but to prove it would take some serendipitous evidence.... I think your idea of creating scenarios is the first step but I do not know that the evidence for any one hypothesis over another has yet to be "unearthed"....

Fri, 19 Nov 2010 17:57:40 UTC | #549995

NealOKelly's Avatar Comment 4 by NealOKelly

Bit of a converstation killer when RD is first to comment! Nothing to add.

Fri, 19 Nov 2010 17:59:23 UTC | #549997

crookedshoes's Avatar Comment 5 by crookedshoes

I am just glad Richard didn't holler "FIRST" when he posted!!! That would really be deflating. BTW THIRD!!!!

Fri, 19 Nov 2010 18:24:50 UTC | #550015

Billy Sands's Avatar Comment 6 by Billy Sands

You may find this interesting if you can access it http://www.sciencedirect.com/science?ob=ArticleURL&udi=B6WNH-4YR8RFG-2&user=10&coverDate=08%2F31%2F2010&alid=1548716471&rdoc=1&fmt=high&orig=search&origin=search&zone=rslt_list_item&cdi=6963&sort=r&st=13&docanchor=&view=c&ct=5&acct=C000050221&version=1&urlVersion=0&_userid=10&md5=960f4526e216ac2303c128d8b2b1f69a&searchtype=a

Sat, 20 Nov 2010 13:18:01 UTC | #550439

Billy Sands's Avatar Comment 7 by Billy Sands

Hmm, the link is not active - search the journal of molecular phyllogenetics and evolution fot "Channa". This new site setup really sucks

Sat, 20 Nov 2010 13:20:06 UTC | #550441

bachfiend's Avatar Comment 8 by bachfiend

According to Timetree, the split between Channa and Parachanna occurred 117 million years ago in the Cretaceous.

Gondwana (which included Africa and India) started splitting up around 130 million years ago, so there's potential overlap between the dates, and you don't need to suggest a "freshwater bridge" between Africa and Asia.

Could humans have been spreading Channa within Asia thousands of years ago too, in the same way that it was introduced into Europe and America as an invasive species? Channa is a prized Asian food fish. It wouldn't be difficult to transfer it short distances in pots.

Sat, 20 Nov 2010 20:44:10 UTC | #550611

SaganTheCat's Avatar Comment 9 by SaganTheCat

thanks for the feedback everyone, i found a link to a recent study of mDNA in an Elsevier journal (April) but I don't have a subscription so I'm hoping it goes open access sometime.

This whole discussion started because I arrogantly pointed out that it's unlikely to be native to both Asia and Africa so probably introduced. This was before we started looking into it and saw they were seperate genera.

I jumped to the assumption that this particular type of air breathing ability was a recent adaption.

Gondwana (which included Africa and India) started splitting up around 130 million years ago, so there's potential overlap between the dates, and you don't need to suggest a "freshwater bridge" between Africa and Asia.

That satisfies my curiosity thanks, although when I say "freshwater bridge", this is pretty much waht I meant

Could humans have been spreading Channa within Asia thousands of years ago too

I'm sure there will have been some human invovlement recently but the fact there are over 30 species in asia alone suggests they've been getting about long before hunans evolved

Mon, 22 Nov 2010 12:35:20 UTC | #551421

jehelm1223's Avatar Comment 10 by jehelm1223

With the introduction of snakefish into north america. What are the long term evolutionary traits associated with this invasive species, that will completely interrupt our eco-system????

  1. Will some of the birds evolve into carnivore lizards with tails due to the changing of their diet???

2.Will there be too many insects for some of the mammals to handle or survive due to the lack of small fish in our watersheds that eat the insects larve.

3.Will the snakefish eventually have to leave the water in search of food and turn reptilian?

4.Will the human food chain be interrupted by the snakefish if toxic insect spray is not applied to our food crops etc.

I posted a topix.com post under the same issue and copy pasted.

Fri, 22 Feb 2013 00:01:07 UTC | #951341