Convergent evolution in dolphins and bats

MichaelMcF
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Convergent evolution in dolphins and bats

Scientists are saying that while sonar evolved independently in bats and dolphins, the sense is similar on the genetic and molecular levels.

 

http://www.cbc.ca/technology/story/2010/01/25/tech-biology-bat-dolphin-echolocation.html

 

 

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 That's really neat...It's

 That's really neat...

It's getting beyond my knowledge of genetics, but I've often wondered about how likely or unlikely it is for the same mutation to happen in genetically distant species.  In the same way that there are a lot of effective ways to see, there are also probably a lot of effective ways to hear.  Then again, there are staggeringly few good mutations, compared to the number of mutations that are either neutral or bad.  

Maybe there are some very specialized abilities that, through their complexity, eliminate all but a few possible mutations.  In other words, we would expect the skill to be quite rare, but when it did pop up, we could make a very reasonable guess as to the mutation that would have had to happen.

 

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Hambydammit wrote: That's

Hambydammit wrote:

 That's really neat...

It's getting beyond my knowledge of genetics, but I've often wondered about how likely or unlikely it is for the same mutation to happen in genetically distant species.  In the same way that there are a lot of effective ways to see, there are also probably a lot of effective ways to hear.  Then again, there are staggeringly few good mutations, compared to the number of mutations that are either neutral or bad.  

Maybe there are some very specialized abilities that, through their complexity, eliminate all but a few possible mutations.  In other words, we would expect the skill to be quite rare, but when it did pop up, we could make a very reasonable guess as to the mutation that would have had to happen.

 

Why is this a surprise? All that distance between species means is that there is distance, but adenine and guanine and thymine and cytosine exist in all species. The only thing that this means is that we have a gap in knowledge as to how this attribute ended up in both. But as you well know, the attribute was not magic.

If we can accept that humans had common ancestors, being that bats and dolphins are both mammals the sonar's path existing in both simply means that the attribute evolved in a common ancestors and ended up in both.

I think you are getting stuck on "sonar" being the "wow" factor when even non-mammals have the same capability.

The reality is that you have no problem with domestic cats having the same attributes as lions and tigers. "Sonar" is merely something you find fascinating.

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Hambydammit wrote:If we can


Hambydammit wrote:

If we can accept that humans had common ancestors, being that bats and dolphins are both mammals the sonar's path existing in both simply means that the attribute evolved in a common ancestors and ended up in both.

I think you are getting stuck on "sonar" being the "wow" factor when even non-mammals have the same capability.

The reality is that you have no problem with domestic cats having the same attributes as lions and tigers. "Sonar" is merely something you find fascinating.

Bats and dolphins obviously have a common ancestor if you go back far enough. However, these species almost certainly did not inherent sonar from that ancestor. Because bats and dolphins are so different, their common ancestor is probably an ancestor of the vast majority of mammal species that exist today. Considering that the majority of mammals do not have sonar we can conclude that these two species probably developed the ability independently, hence convergent evolution. Similar genetic traits  being produced in two completely different environments is a pretty big deal.


 

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MichaelMcF wrote:similar on

MichaelMcF wrote:

similar on the genetic and molecular levels

 

I strongly suspect that our understanding of "convergence" in it its infancy - to put it mildly.

It would be interesting to see a broad study into the structural dispositions for the developent of all kinds of senses, in correlation to what specific functions they are serving. What I mean to say is that even in a dynamic and very complicated pattern of molecular events, there might be only 3 or 4 possible options at each crossroad, but that in an ever rising hierarchy of complexity and emergence, these produce ever more bizarre forms of seemingly great difference and individuality.


 

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Marquis wrote:MichaelMcF

Marquis wrote:

MichaelMcF wrote:

similar on the genetic and molecular levels

 

I strongly suspect that our understanding of "convergence" in it its infancy - to put it mildly.

Agreed.  Our current understanding of molecular-level evolutionary theory doesn't exactly paint a complete picture - Consider the mounting evidence for trans-generational epigenetic changes in some phenotypes.  It's been seen in mice and some cell cultures when exposed to specific environmental stresses.  No direct genetic change, but alterations in expression or molecular markers (histones/nucleotide methylation).

It's going to be an exciting century! 

Faith is the great cop-out, the great excuse to evade the need to think and evaluate evidence. Faith is belief in spite of, even perhaps because of, the lack of evidence.
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Brian37 wrote:If we can

Brian37 wrote:
If we can accept that humans had common ancestors, being that bats and dolphins are both mammals the sonar's path existing in both simply means that the attribute evolved in a common ancestors and ended up in both.

Oh, no no no. The entire point was that similar complex functions seem to be able to evolve independently of each other despite the differences in the gene pool and environment, that a similar trait was NOT present in the common ancestor.  

Edit: Aww dammit! Someone else already said it better.

Our revels now are ended. These our actors, | As I foretold you, were all spirits, and | Are melted into air, into thin air; | And, like the baseless fabric of this vision, | The cloud-capped towers, the gorgeous palaces, | The solemn temples, the great globe itself, - Yea, all which it inherit, shall dissolve, | And, like this insubstantial pageant faded, | Leave not a rack behind. We are such stuff | As dreams are made on, and our little life | Is rounded with a sleep. - Shakespeare


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 Right.  The whole point

 Right.  The whole point is that despite having a common ancestor at some point, sonar and echolocation, which are very similar abilities, developed separately.  That in itself is not particularly astounding.  The eye has developed at least 8 separate times.  What is interesting is that the genetic mutation that gave rise to both echolocation and sonar appears to have been the same.  

In other words, evolution hit a royal flush twice.  The odds against it are pretty bad.  Of course, this leads to the question of whether there's some mechanism in place that makes this convergence more likely.

 

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Agreed

Natural_SciGuy wrote:

It's going to be an exciting century! 

 

Wish i was 20 so i could be here for even more of it. P'raps this will be the century we unravel the last great gaps. I wonder how far the christian mind will need to bend to reinterpret of all the additional knowledge? One thing is certain. Bend they will...

 

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Marquis
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Atheistextremist wrote:One

Atheistextremist wrote:

One thing is certain. Bend they will... 

 

The Japanese are a bunch of weird mo-fo's, but they have some neat proverbs, and this one applies here:

"The bamboo must bow to the wind."

Speaking of age, I am of the impression that you're just a couple of years younger than me, which means that you can at least brag about remembering the Cold War and the 80's and all that stuff. On an ending note I will say: Surely, you do not wish to be 20 ever again?!? Man, that sucked...

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I got the sense that the

I got the sense that the article was over-playing the find. Two reasons: First, I didn't see any mention of how many mutations there were in the prestin protein coding sequence. They didn't say how many mutations were important for echo-location, and they also didn't mention if there were any other neutral mutations, such as you might expect for any two species separated for so long. At first click, it shrieks of selectively listening to and amplifying the convergent evolution aspect, while tuning out the background noise of neutral mutations. (Like those metaphors?)

Second, one protein does not an echo-location sense make. There are undoubtedly thousands of other mutations involved in echo-location. The prestin protein reminds me of the human FOXP2 gene, which plays a crucial role in human language ability, but which should not be considered 'the' human language gene, since there are countless other genes involved in language as well.

Ancestral prestin probably had a structure which by fluke happened to be one that, with a few choice mutations, would enable hearing a different set of frequencies than usual. But that alone is not enough for sophisticated echo-location. Give a human the same mutations and they wouldn't suddenly be able to see in the dark. (Interestingly, though, human echolocation is a learnable skill, even without this mutation.)

So, if the potential for these beneficial mutations was already there, all it took was a new environment where echolocation would be highly beneficial, and evolution will automatically do the work to find those few easy mutations. It's like low-hanging fruit. Some fruit just happens to be lower-hanging than others, and it's no surprise that two different species sharing a copy of the same tree might pick the same few fruits. Doesn't happen often, but I think the article over-played its significance.

Still, an interesting story. Not as cool as the photosynthetic slug! Laughing out loud

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Brian37
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Hambydammit wrote: Right.

Hambydammit wrote:

 Right.  The whole point is that despite having a common ancestor at some point, sonar and echolocation, which are very similar abilities, developed separately.  That in itself is not particularly astounding.  The eye has developed at least 8 separate times.  What is interesting is that the genetic mutation that gave rise to both echolocation and sonar appears to have been the same.  

In other words, evolution hit a royal flush twice.  The odds against it are pretty bad.  Of course, this leads to the question of whether there's some mechanism in place that makes this convergence more likely.

 

Now Hambi, there is a "mechanism". "God did it".........you should know that by now. After all billions of people cant believe false things.

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