Evolution: Science or Dogma?

[carlosMM]

Any biologists out there please correct me if Im wrong, but Ive read that humans and chimpanzees are so closely related they could breed and produce viable offspring.

IIRC - no! it starts with the obvious duration difference in pregnancy (only Gorillas have 9 months like humans), and the immune difference is huge! 1% difference here includes MHC2 proteins - the cell's passport. Oops! That embryo is a foreigner.......kill it!

No, humans and other great apes are too far apart.

 

[Bozo Erectus]

Carlos oh ok, I read lots of things, not all are accurate unfortunately. How about donkeys and horses? Are humans and chimps more far apart than they are? One thing I read about this was that the Soviets conducted some experiments with human/chimp sperm - egg fertilization. IIRC fertilization took place and the cells began dividing but they terminated them before they got very far. Its true, a testtube is one thing, and carrying a viable offspring to full term and delivering it alive is a completely different matter, but I always thought this was fascinating (if true).

 

[carlosMM]

DP: horses and donkey are indeed much closer than man and chimp! And even they can't produce fertile offsprings normally.

Just look at the bones and try tot ell them apart: man-chimp is easy, donkey-horse is tough!

the testtube thing has no immune system of the mother body present sperms and eggcells are so basic that you cna get them to do much between species. An amniote egg is an amniote egg. Also, the INITIAL development of a fertilized egg is very basic. Changes here will usually be lethal. So little change took place. Much as some pieces of DNA are extremely old and unchanged.

I guess the first time major specialization of cells would happen the embryo would die.

 

[Bozo Erectus]

Thanks for clearing that up Carlos One more thing for me to move from my Science Fact folder, to the Science Fiction folder.

 

[bigfatron]

This 'kind' v 'species' debate is damned confusing to me - I'm at a loss to see what the difference is between these two terms:

From Dictionary.com;
spe·cies ( P ) Pronunciation Key (spshz, -sz)
n. pl. species
Biology.
A fundamental category of taxonomic classification, ranking below a genus or subgenus and consisting of related organisms capable of interbreeding.

This seems to fit with FL2's definition whereby the key defining factors were similarity ('related organisms') and an ability to pass on their distinguishing features to descendants ('capable of interbreeding').

If 'kind' and 'species' don't mean the same thing, can someone explain in what ways the terms differ?

 

[carlosMM]

This 'kind' v 'species' debate is damned confusing to me - I'm at a loss to see what the difference is between these two terms:

From Dictionary.com;
spe·cies ( P ) Pronunciation Key (spshz, -sz)
n. pl. species
Biology.
A fundamental category of taxonomic classification, ranking below a genus or subgenus and consisting of related organisms capable of interbreeding.

This seems to fit with FL2's definition whereby the key defining factors were similarity ('related organisms') and an ability to pass on their distinguishing features to descendants ('capable of interbreeding').

If 'kind' and 'species' don't mean the same thing, can someone explain in what ways the terms differ?

I once asked FL2 just that question, after we had bedgered him into giving a good definition of kind. he ended up very near species.
He accused scientists of not coming up with a agood definition for 200 years until he 'had to do it for [them]'.

Then, he proceeds to name 'kinds' that aren't species



FL2, can you finally admit that if the bible is to make any sense on this then 'kind' must be the scientific 'species'?

remember, though, that your insistence that a 'kind' includes a fdar wider variety than a biological species was a key arguement you used to defend Noah's Ark! You admitted that not all species could ahve been abord, but claimed that this wasn't necessary, all 'kinds' were sufficient. So if now you admit that 'kind'=species you will admit that the biblical flood tale is not to be talken as fact!

 

[FearlessLeader2]

Primates would be a kind, but noone would mistake an orangutan for a capuchin monkey. The others aren't even that close.

What part of 'would be ... but' means 'is' to you?

 

[Bozo Erectus]

Depends on what your definition of 'is' is.

 

[WillJ]

A kind is exactly what I said it was. A group of creatures that share enough common traits to be visually identified with each other, but dissimilar enough to other creatures as to not be identified with them. They also have to be able to reproduce and have offspring that retain those similarities and differences.

Correct me if I'm wrong, but that means that a "kind" is actually MORE exclusive than a "species," because a species only requires members to be able to have fertile offspring with each other, whereas "kinds" apparently also take into account visual differences, and thus black people and white people, or German Shepherds and Golden Retrievers, could be considered different kinds.

If it's true that FL2 said that it'd have been impossible to fit all species on Noah's ark (I'm too lazy to check), then FL2, you're going to have to work on a definition of "kind" that DOESN'T include the ability to reproduce.

 

[Perfection]

What part of 'would be ... but' means 'is' to you?

So then why are snakes in the same kind?

 

[Blasphemous]

So then why are snakes in the same kind?

Because FL2 has a hard time telling them apart sometimes of course.

 

[carlosMM]

What part of 'would be ... but' means 'is' to you?

well, if they would be a kind according to your definition, but aren#t - then may it perhaps be your definition sucks?


and you could, just for a change, answer the rest of my post, too!

 

[CrazyScientist]

Are we still on this kind thing?
A group of organisms contained by a force of genetic cohesion (in most cases gene exchange, but there are others) has a cap on the level of divergence that can arise between any two populations within it. That is, there is a limit to how different two populations of organisms can become from one another, even in the face of diversifying selection, as long as gene exchange is going on. Once gene exchange stops occuring (sometimes for geographical or ecological reasons first, but eventually for physiological reasons), the barrier comes down. Populations are then fully at the mercy of the selection pressures of their environments and are capable of divergence without bound. They are also irrevocably seperate at that point, and will never ever be the same species again no matter what happens. If they remain under similar selection pressures they might continue to look very similar. If they are brought back into sympatry and retain ecological similarity one might outcompete the other to extinction. But the speciation event is irreversable once the cohesive force of genetic exchange is gone.
All the higher taxonomic groups are somewhat arbitrary compared to this. They just denote groups of organisms with common features due to common ancestry. Every new genus, family, order, class, and phylum originated with a speciation event not too different from any other speciation event, just longer ago.
Species is the only classification that has any biological relevance. Either species are kinds, or all organisms are one kind. No other designation of kind makes any sense within the framework of population biology.

Edit: Another thought just occured to me. A question for FL2 or one of our other religious posters. I understand Genesis says creatures reproduce after their own kind. Evolution does not conflict this statement by itself. The vast majority of the time they do. Does Genesis specifically say that creatures reproduce after their own kind and only their own kind? Honestly just curious. I'm wondering if there's a loophole in there that might allow for speciation.