My question is about Dog breeding and evolution. Is dog breeding an example of macro-evolution? Correct me if I'm wrong, but isn't the seperation of  species defined as the inability to produce offspring that can reproduce? Man kind has created over 150 dog breeds, and I'm going to assume that this

Will not be able to mate with this

I guess there's a lot that goes in to answering that question, how much variation in species was there before human interference (which itself stretches back as far as the human race), can severly different species of dogs, though incapable of breeding themselves, breed with dogs a bit closer to themselves, and then have their offspring breed with closer species of dogs. And if so, then would that still constitute macro evolution since all that is necessary to meet the species criteria would be for those intermediary dog breeds to die out?

Someone help me. What exactly have we done to dogs over the course of history?

On an unrelated note, I didn't know we had made a breed of dog that could fly.. cool.

Isn't there a Wikipedia page that can answer all these questions?

I might be wrong, but I don't think a speciation event has actually occurred with dog breeds. The two dogs you showed almost certainly would not breed, which in the wild would eventually lead to a speciation event. However if I'm not mistaken (and I may very well be) it's possible to make a great dane chihuahua mix (and other bizarrities) through artificial insemination, however it's also cruel and their will be considerable hereditary problems.

Domestic dogs are probably on the verge of a speciation event seeing as how the genetic differences are becoming great enough that cross breeding between certain breeds is incredibly difficult, and the results can be very bad. Which is the normal course. A speciation event doesn't happen all at once, but rather the likely hood of being able to produce offspring between populations becomes less and less until it reaches zero or something so close to zero it might as well be zero.

The question is can humans continue to push them genetically. Dogs aren't bred for survival, they are bred for show or other desirable attributes which leads to alot of very unhealthy breeds. Can people or should people continue to mess with the genetics of dogs for show? But that is a whole different topic.

Well think of it this way, you can make as many breeds as you want...but they will always be dogs.

I don't think a speciation event has occurred with dog breeds

But different species can sometimes breed, too (lions and tigers can breed, and so can donkeys and horses)

If humans stopped interfering dogs would return to a single form over a relatively short period of time. They are still the same species, this is because they are essentially spread over the same range and are able (and willing) to mate with each other and produce viable offspring.

The German Shepard x Chihuahua problem is easily solved by them mating with intermediate dogs.


The only barrier to their reproduction is humanity, which is an artificial barrier.

0_o

I would love to know what a cross breed between a lion and tiger looks like.

I don't remember if there was an actual difference between a liger and a tigon (I think they're just different names) but here they are:

An 8 foot tall man would likely have a very, very hard time having sex with a 3 foot tall woman. Chances are, that 3 foot tall woman could only mate with a 3 foot tall man, and vice versa for the 8 foot tall man. But at the same time, it's unlikely that either of the groups would become their own species. Or maybe I missed your point here.