Evoluation makes no sense to me now!!!

[hellheaven1987]

http://news.yahoo.com/s/afp/20080507...s_080507184740

Now scientists know why. According to a study released Wednesday, the egg-laying critter is a genetic potpourri -- part bird, part reptile and part lactating mammal.

Can someone explain what is going on???

[Blau&Gruen]

Bird, Reptil and Mammal are phylogentical related. Why should a species not have traits of several phylogenetic groups?

[Yuiis]

If you see fetus from different animals (including humans) you can notice that specially in the first days and weeks of pregnancy they are extremely similar. We all come from the same unicelular beings, so it is logic to think that we hold lots of genetic similarities with the other animals surrounding us. Even if we dont use some of those genes, we still carry them for some reason or another.

[rathelios]

Can someone explain what is going on???

Recommend reading to paragraph four of the article. It may help.

"The platypus genome is extremely important, because it is the missing link in our understanding of how we and other mammals first evolved," explained Oxford University's Chris Ponting, one of the study's architects.
"This is our ticket back in time to when all mammals laid eggs while suckling their young on milk."

indeed.

Anyhoo, isn't Chris Ponting in Jackass?!

[Adar]

What those crazy scientists has done now is that they have researched the genome of the mammal that is as far us as possible on the phylogenetic tree. Essentially the platypus is almost as closely related to us (our group of mammals) as it is to birds. Therefor they can use the platypus to determine what genetic abilities were gained before and after the separation of mammals and birds (example here), essentially it gives us a greater understandin how we came to be. Of course the platypus has also been subject to alot of natural selection throughout the millions of years but the research is value to see what have previously been shared between birds and mammals but then diverged.

If the platypus and birds share a gene sequence is it indicative that it was present at the time when mammals and birds had the shame ancestor but that it subsquently have been lost later among mammals. The viceversa is also true but less accurate, the presence of a gene among birds but not among platypus and other mammals means that it either has developed in birds after the split from mammals or that it in a later time has been lost in both platypuses and mammals (and we don't know which case is true).

Basicly this is history for a genetecist. On a sidenote, if the genome of the platypus had been consisting of randomly selected genes from fishes, amphibians birds and mammals would the scientists have accidently disproved evolution as we understand it since we expect the platypus to be most similar to mammals, secondarily to birds and thirdly to reptilians (we could of course just have misplaced the platypus on the phylogenetic tree but there is so much other evidence that it is correctly placed that would be improbable).

[hellheaven1987]

But... from what I remember birds were evolved from reptile!!

So, does that mean mammal also evolved from reptile too??

[Chiron202]

But... from what I remember birds were evolved from reptile!!

So, does that mean mammal also evolved from reptile too??

Yes, yes it does. The evolution of mammals from reptiles is very well documented in the fossil record. Our ear bones are jaw bones in reptiles. (They have several, we have one.) Therapsids are the first recognizable "proto-mammals" which then evolved into the Cynodonts, followed sometime by Mammals proper. Therapsids were closely related to Dimetrodon, that dinosaur with the big fan on its back for heat-sinking, which is pretty cool to me, being a huge dinosaur geek when I was little...

Adar, I own that shirt in your avatar, and it gets the best looks from kids at my semi-conservative religious college... But of course the bio profs love it...

[Valentin the II]

Yes, yes it does. The evolution of mammals from reptiles is very well documented in the fossil record. Our ear bones are jaw bones in reptiles. (They have several, we have one.) Therapsids are the first recognizable "proto-mammals" which then evolved into the Cynodonts, followed sometime by Mammals proper. Therapsids were closely related to Dimetrodon, that dinosaur with the big fan on its back for heat-sinking, which is pretty cool to me, being a huge dinosaur geek when I was little...

Adar, I own that shirt in your avatar, and it gets the best looks from kids at my semi-conservative religious college... But of course the bio profs love it...

Problem is, birds evolved from dinasaurs we didnt (Dimetrodon is not a dinosaur).
Dinasaurs are far more advanced than the reptiles we evolved from.


Acording to this the platipus should not exist.

[rathelios]

It seems Simetrical is not here right now so I'll answer this vaguely seriously. I'm not that scientifically literate so I'm shamelessly plagurising. Sim can insert corrections as appropriate - or not. It breaks down like this:

The platypus evolved from an early kind of mammal. Some geneticists sequenced the platypus genome. As expected its genes are a mix of reptilian and mammalian features because mammals evolved from reptiles.

However:
The gene sequences that determine platypus sex are more like a bird's than a mammal's. The gene that determines sex in humans is present but it is doing a different job in platypuses. So the function in humans (and all other mammals except monotrenes) must have evolved after our common ancestor split from platypuses (about 166 million years ago). The platypus has the same repetoire of milk protein genes as all the other mammals so clearly this evolved before the ability to have live offfspring.

Note that no one said its sex gene is the same as a birds, just similar, so there is no need to rewrite history here. This draft sequence shows that platypuses split off a branch of the evolutionary tree that leads to both placentals and marsupials.

Clear as Mudd?

[Chiron202]

Problem is, birds evolved from dinasaurs we didnt (Dimetrodon is not a dinosaur).
Dinasaurs are far more advanced than the reptiles we evolved from.
Acording to this the platipus should not exist.

I just referred to it as a dinosaur because that is how the vast majority of people would identify it casually. I'm invoking colloquial use of dinosaur here, not the Superorder, Dinosauria.
So aside from that point, I have no idea how my post invoked birds, or whatever your objection is getting at...

[boofhead]

Well, I for one am the direct descendent of a miniature slimeball amphibian trilobite. Makes perfect sense!