themadhair
Well-Known Member
I asked mine but I dont think the answer has been discovered just yet
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Questions about Evolution?
- Thread starter painted wolf
- Start date
painted wolf
Grey Muzzle
Is there a follow up about the ratchet that you wanted to ask?
wa:do
wa:do
themadhair
Well-Known Member
When I do searches on the molly for recent papers it seems that most of them conclude that it is likely other additional as-yet-undiscovered mechanisms are involved. Sexual recombination, compensatory mutations, etc. are all possibilities for explaining the non-extinction. But, AFAIK, none of the known mechanisms are believed to be sufficient thus far.
In the simulations the VSDM are generated using a fixed selection pressure. I suspect this may possibly skew the results due to nature not having such unvarying selection pressures, but Im not a biologist and Im not involved in this research.
painted wolf
Grey Muzzle
Computer models are only as good as their set variables.
It is true that this is an area that needs more research... often times factors such as funding, resources and the limitations of the original question asked can keep a study from initially finding the answer to a particular problem.
It could also be (and it often is in biology) that there is no one single answer to the question. It is likely to be a variety of contributing factors to why the Molly resists the ratchet. Now that some of those factors have been pointed out, work on how much if any influence they have needs to be done.
I find this part of the paper interesting:
Perhaps the occasional tetrapoloid individuals play a greater role than previously thought?
here are a couple other papers on the subject (which I wish I had more time at the moment to dig into)
Dispensable and indispensable genes in an ameiotic fish, the Amazon molly <i>Poecilia formosa</i>
A Tetraploid Amazon Molly, Poecilia formosa -- Lampert et al. 99 (2): 223 -- Journal of Heredity
Distribution and stability of supernumerary microchromosomes in natural populations of the Amazon molly, <i>Poecilia formosa</i>
wa:do
It is true that this is an area that needs more research... often times factors such as funding, resources and the limitations of the original question asked can keep a study from initially finding the answer to a particular problem.
It could also be (and it often is in biology) that there is no one single answer to the question. It is likely to be a variety of contributing factors to why the Molly resists the ratchet. Now that some of those factors have been pointed out, work on how much if any influence they have needs to be done.
I find this part of the paper interesting:
With culture rejection, some sort of significant genetic change is going on.
Perhaps the occasional tetrapoloid individuals play a greater role than previously thought?
here are a couple other papers on the subject (which I wish I had more time at the moment to dig into)
Dispensable and indispensable genes in an ameiotic fish, the Amazon molly <i>Poecilia formosa</i>
A Tetraploid Amazon Molly, Poecilia formosa -- Lampert et al. 99 (2): 223 -- Journal of Heredity
Distribution and stability of supernumerary microchromosomes in natural populations of the Amazon molly, <i>Poecilia formosa</i>
wa:do
crunk-juice
Senior Member
this might not make sense because i have trouble putting my thoughts into words sometimes. i just have a hard time seeing how "random chance" can make little lifeless molecules into what we are today. i find it amazing that there can be something that is actually conscious of the universe, when there must have been a time when there was no such thing as life. i just don't understand how lifeless can become life.
also, wouldnt that take an unimaginable amount of time? i know they say it took millions and millions of years, but it just seems like the amount of time the earth could have been here wouldnt even be enough time. wouldnt there be countless failed "attempts"? just for everything to come together so perfectly seems so unlikely. i know some will argue that we are far from "perfect", but come on. just look at us.
for the record, i am a devout atheist and am in no way advocating creationsim. i know evolution happens, just certain aspects are hard to understand. could there be something more? not "god", but just something we have no ability to comprehend? again, i'm sure that makes no sense to others. it's hard to explain.
also, wouldnt that take an unimaginable amount of time? i know they say it took millions and millions of years, but it just seems like the amount of time the earth could have been here wouldnt even be enough time. wouldnt there be countless failed "attempts"? just for everything to come together so perfectly seems so unlikely. i know some will argue that we are far from "perfect", but come on. just look at us.
for the record, i am a devout atheist and am in no way advocating creationsim. i know evolution happens, just certain aspects are hard to understand. could there be something more? not "god", but just something we have no ability to comprehend? again, i'm sure that makes no sense to others. it's hard to explain.
AbuKhalid
Active Member
Male mosquitos have receptor cells in their antennae which are set to pick up the sound of the female wings which are beating at a particular speed. This is how they find each other to mate. If the mosquito exists by coincidence then why do the male wings beat at a particular speed and the female ones at a particular speed and why not all different speeds? How did the female wing speed "evolve" and the male antennae "evolve" completely separately and by chance, yet they are perfectly matched? It seems to me that this is a system which would have been required to come about in both sexes at once in order for it to be viable. Maybe someone could explain.
painted wolf
Grey Muzzle
Lets see how well I can get my brain working this morning...
First off you need to rethink "random chance"... The molecules that make up life are not acting according to random anything... they are acting under the rules of basic chemistry.
This basic chemistry would have been playing out all over the early Earth for millions (if not a billion) of years before we got to anything you would remotely think of as 'life'. Just as it doesn't take 'unimaginable' amounts of time for things like lipids to form hollow spheres to act as cell walls... it wouldn't take 'unimaginable' time for the other basic parts of a cell to come together.
No doubt that countless of these early precursors to what we know as life today have existed and been out competed by others. Remember the "simple cells" you see today are the result of 3 billion years of evolution... the first cells would have been so simple they would make something like E.coli look as darn sophisiticated as it really is.
As a Biologist I can tell you that while magnificent in scope.. things didn't "come together perfectly" for life. We have come a long way for a bunch of self replicating cells... No doubt about that.
The road to us humans has been a rocky one... filled with oddity and grandeur... be proud of your ancestors.
For the record I'm a theist and have a strong faith in Creator... but I'm also a Biologist and ignoring the truth in the world around me seems like a silly gesture.
wa:do
painted wolf
Grey Muzzle
Because they don't exist by coincidence. Evolution is not "random chance" or "coincidence" but a set of rules that govern how the outside forces of the Earth and the inner forces of Genes interact and change.
They didn't... they evolved together through a process called sexual selection.
Males who are better at seeking females are the ones who have baby mosquitos... Males want to find females of the same species. Female mosquitos who are better at attracting males are the ones that have baby mosquitos... Females want to be found by males of the same species.
Over the many millions of years that mosquitos have been around they have had plenty of time to hone this ability and each mosquito species develops it's own sound to attract the right kind of potential mate.
That's generally how it works. Sexual selection works on both sexes.
(mosquito reproduction is a tad more complex than males listeneing for female buzzing... but It's a good question and hopefully I've helped clear up sexual selection a bit.)
wa:do
themadhair
Well-Known Member
You have no idea how many failed attempts will never be known about.
Well, the earth is roughly 4.5 billion years old. That is an almost unimaginable amount of time. Your imagining perfection by your own standards. There have been tests done, that show life can come from non life. So, it is definitely possible for that to happen.
linwood
Well-Known Member
It is amazing.
Until recently I held the same belief as you.
"Life had to have a beginning".
Someone somewhere on this board stated they didn`t see why it had to have a beginning.
Matter is eternal.
Energy is eternal.
Space is infinite.
Why not life?
A discussion for another thread.
painted wolf
Grey Muzzle
Define life...
we have a very biased view of what life is... we only have ourselves to look at.. but things like viruses and prions hint at a wide variety of chemical 'life' that could exist... some of it under our very noses.
wa:do
we have a very biased view of what life is... we only have ourselves to look at.. but things like viruses and prions hint at a wide variety of chemical 'life' that could exist... some of it under our very noses.
wa:do
OmarKhayyam
Well-Known Member
I have a kinda odd question. Some background.
I bought this tree for the "oddity" sake. (And I need trees in my barren yard.)
Dawn Redwood
My question is how is it that this tree survived. This story reads like "Land of the Lost."
If the place it was found was the only stand left what was so different there? Would there be other really old plants there? If not why not?
I bought this tree for the "oddity" sake. (And I need trees in my barren yard.)
Dawn Redwood
My question is how is it that this tree survived. This story reads like "Land of the Lost."
If the place it was found was the only stand left what was so different there? Would there be other really old plants there? If not why not?
themadhair
Well-Known Member
By not dying out?
I think your question is asking why they seem not to have evolved but they have. IIRC correctly its sister species are extinct and it is the only one left in its genus. Are they still on the Red List?
painted wolf
Grey Muzzle
Well, first off... this is what is called a "relic species". It's not the same species as what lived so long ago, but it's modern descendant.
They survived like any other species does... good luck and tenacity.
it's close relative the Sequoia also has a limited range, though not quite as limited. These types of trees like very specific conditions to be really happy and during the ice age those conditions were limited to small geographic areas. Some rebounded well, like the Sequoia and some didn't rebound as well... the Dawn Redwood.
Essentially the Dawn Redwood was going extinct and was thankfully discovered in time to prevent this.
You aren't likely to find other really old plants around because it's not the place that is old per say... that just happens to be where this once thriving group is making it's last stand.
wa:do
as for the Red list... yes and no... the original wild population of 5,000 will likely go extinct. People have been so eager to grow them elsewhere that the wild population hasn't been able to reproduce. All the seeds are gathered and grown around the world. However they won't truly go extinct as they are now a major decorative tree that is still in good demand. Also a few 'experimental' forests have been planted to act as surrogate wild populations.
They survived like any other species does... good luck and tenacity.
it's close relative the Sequoia also has a limited range, though not quite as limited. These types of trees like very specific conditions to be really happy and during the ice age those conditions were limited to small geographic areas. Some rebounded well, like the Sequoia and some didn't rebound as well... the Dawn Redwood.
Essentially the Dawn Redwood was going extinct and was thankfully discovered in time to prevent this.
You aren't likely to find other really old plants around because it's not the place that is old per say... that just happens to be where this once thriving group is making it's last stand.
wa:do
as for the Red list... yes and no... the original wild population of 5,000 will likely go extinct. People have been so eager to grow them elsewhere that the wild population hasn't been able to reproduce. All the seeds are gathered and grown around the world. However they won't truly go extinct as they are now a major decorative tree that is still in good demand. Also a few 'experimental' forests have been planted to act as surrogate wild populations.
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Im an Atheist
Biologist
The base pairs not aligning properly in the DNA when recoiling IAA
Halcyon
Lord of the Badgers
It's not so much probalems of alignment as it is mistakes being made when the DNA is replicated, such as a guanine being replaced with an thymine, talking specifically about point mutations.
Bigger mutations could come about by large portions of DNA being accidently moved from one chromosome to another, disrupting genes already present and possibly creating new ones.
Retroviruses can insert genes into DNA from other areas of the same genome, or in rare cases from different species.
There are others.
For any mutation to be passed on though it needs to either occur in the embryo so that it is present in every cell of the adult body, or specifically in the germ cells that produce sperm or eggs. Germ cell only mutations could occur, again via retroviruses or from exposure to mutagenic chemicals or radiation.
Halcyon
Lord of the Badgers
According to wikipedia the first bilaterally symmetrical animal was something called Kimberella. Presumable bilateral symmetry would have evolved from radial symmetry.
Just me speculating, but I imagine the cause would have been localisation of sense organs to a single area making that the logical "front" of the creature, meaning it would most likely move in the direction it could best sense. Once you have a front you'd have a back, and it's only a matter of natural selection introducing features that aid in the locamotion toward the front that creates the basic design.
painted wolf
Grey Muzzle
One of the first fossils of bilaterally symmetrical animals... 
Genetics indicates they are a bit older still then Kimberella (a protostome) and fossil embryos that resemble those of bilaterally symmetrical animals have been found that are from around this time.
Our fellow Deuterostomes the Echinoderms are as adults classic examples of radial symmetry. But, as embryos they are bilateral like us. Also the Anemone Nematostella vectensis is bilaterally symmetrical and uses homologus genes to develop this body plan.
What happened to cause this was a reshuffling of Hox genes. We bilaterians have essentially maintained the larval body plan. Keeping our Hox and another gene Dpp localized around our main axis rather than branching out.
So the advent of bilateral symmetry predates the Deuterstome/Protosome split... some time after the Anemonies figured it out. This group has been called Urbilateria and it shows up nicely in our shared genetic heritage.
If you look at the Edicardian fauna you see some organisms that are bilaterally symmetrical. It's almost certian that these guys were using the same tricks with their Hox genes as we do.
Wether or not they are our Urbilatrians has yet to be determined. A lot of research still needs to be done of the Edicardian fauna.
Here for example is Spriggia (possibly an arthropod ancestor)
It's all about the Hox genes.
Hope this helps... if you have any specific areas you want touched on more let me know.
wa:do
Genetics indicates they are a bit older still then Kimberella (a protostome) and fossil embryos that resemble those of bilaterally symmetrical animals have been found that are from around this time.
Our fellow Deuterostomes the Echinoderms are as adults classic examples of radial symmetry. But, as embryos they are bilateral like us. Also the Anemone Nematostella vectensis is bilaterally symmetrical and uses homologus genes to develop this body plan.
What happened to cause this was a reshuffling of Hox genes. We bilaterians have essentially maintained the larval body plan. Keeping our Hox and another gene Dpp localized around our main axis rather than branching out.
So the advent of bilateral symmetry predates the Deuterstome/Protosome split... some time after the Anemonies figured it out. This group has been called Urbilateria and it shows up nicely in our shared genetic heritage.
If you look at the Edicardian fauna you see some organisms that are bilaterally symmetrical. It's almost certian that these guys were using the same tricks with their Hox genes as we do.
Wether or not they are our Urbilatrians has yet to be determined. A lot of research still needs to be done of the Edicardian fauna.
Here for example is Spriggia (possibly an arthropod ancestor)
It's all about the Hox genes.
Hope this helps... if you have any specific areas you want touched on more let me know.
wa:do