A recent article in Nature reports on a fish that has a pelvic girdle with features associated with terrestrial vertebrates.
Discuss.
Walking Fish - evolution or adaptation?
by Earnest 11 Replies latest watchtower beliefs
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cofty
Hi Earnest.
I saw that headline but have not read it yet. Do you have a link?
What do you mean by "evolution or adaptation?"
Evolution is something that happens to a population. It involves changes in the DNA code. Fish first emerged onto dry land around 380 million years ago. A good example from that period is Tiktaalik...
Some ray finned fish evolved lobe fins with larger stronger bones that are analogous to our limb pattern. Initially the advantage would probably involved moving along the bottom of rivers or ponds. Perhaps that became the ability to move along very shallow bodies of water.
Given the advantages of being able to move from pond to pond it's not surprising life has discovered this more than once.
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DogGone
I'm confused. Evolution is the long accumulation of adaptations that provide selective advantage. Where is the OR? It is like asking, Bingo - Charity fund raiser or game of chance?
The answer is "yes".
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Earnest
Hi cofty,
Apologies ... my original post had a link (http://www.nature.com/articles/srep23711). My question about evolution and/or adaptation is because I think the subject is far from the simple, elementary way that evolution is sometimes portrayed. I recently went to a day of talks on the subject and while all of it was fascinating, there was a recurrent theme that there is a lot that we don't know and cannot explain.
One interesting question from the audience was that it is understood there is a common ancestor to all living things. Why is there only one common ancestor? Why is there no evidence of other "common ancestors" which were not as successful? Was there no competition to be the "first" common ancestor?
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DogGone
Was there no competition to be the "first" common ancestor?
Perhaps, but something won and it proliferated so much that the record shows a single tree. You are talking here about the actual origin of life, right? Because early on there are plenty of phyla that got lopped off. That is, plenty of early life patterns that did not win the competition.
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cofty
Why is there no evidence of other "common ancestors" which were not as successful? Was there no competition to be the "first" common ancestor? The answer given was we don't know.
Yes indeed!
Unless LUCA the loser left some clue in the genes of LUCA the winner!
You are right there is so much of the details we don't know.
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cofty
Thanks for the link Earnest. I will have a read later -
Mephis
Why is there only one common ancestor? Why is there no evidence of other "common ancestors" which were not as successful? Was there no competition to be the "first" common ancestor?
There are certain basic building blocks (eg DNA/RNA and the genetic code) to all known life on Earth which implies a specific way in which life came to be - 'the common ancestor'. Until the mechanisms of how that initial life came to be are known for sure, or at least to a high degree of probability, then the 'why' and related questions are unanswerable really. One of the reasons finding evidence of life elsewhere within the solar system (and beyond) would be so important is that it would help to begin to identify the causal factors more precisely. But so far as we know currently, life exists on Earth and it's all based upon the same basic building blocks and has a common origin. If there were other forms of life on Earth then they are obviously no longer with us and would seem to also be beyond our ability to detect. I don't think the mystery so much lies with 'alien' life on Earth, life here is adapted for Earth, but in how (if) life develops elsewhere and in different conditions.
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Island Man
There's something wrong with premise behind the OP let me point it out by way of an illustration. Imagine you read an OP like this:
A puppy increasing in size as the months go by - growth or cell-division?
