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Yep.
Yep.
Of course, I do not understand the mechanism by which so great a mutation occurs, to change one species into another. A change of feather color or shape, yes, a shift of body carriage or beak shape, yes. But given that most mutations are deleterious to the creature, and lead to it being eaten or otherwise vanishing from the gene pool in a hurry....
Yes, most mutations are deleterious. But given millions upon millions of years, you have more than enough time for the occasional positive mutation to make a difference. Most people think that there's some kind of firm line that exists when species divide, but that's not really what happens. What happens is that populations gradually get separated and follow their own evolutionary paths, to the point that they no long mate with the other group due to disinclination or physical impossibility, or both. When that happens they are deemed to be distinct species. So talking about a non-chicken laying an egg that hatches a chicken, while technically correct, presents the wrong impression. What actually happened was that a bird that was highly chicken-like laid an egg that hatched a bird that was even more chicken-like (that is, more like the designation for chickens we have today), and that bird qualified genetically as Gallus Gallus.
According to biologist Dana Krempels ,
Yes, most mutations are deleterious. But given millions upon millions of years, you have more than enough time for the occasional positive mutation to make a difference. Most people think that there's some kind of firm line that exists when species divide, but that's not really what happens. What happens is that populations gradually get separated and follow their own evolutionary paths, to the point that they no long mate with the other group due to disinclination or physical impossibility, or both. When that happens they are deemed to be distinct species. So talking about a non-chicken laying an egg that hatches a chicken, while technically correct, presents the wrong impression. What actually happened was that a bird that was highly chicken-like laid an egg that hatched a bird that was even more chicken-like (that is, more like the designation for chickens we have today), and that bird qualified genetically as Gallus Gallus.
According to biologist Dana Krempels ,
The very first organisms that produced an amniotic egg were terrestrial, reptile-like animals that didn't have feathers. But one branch of this lineage did evolve and give rise to the feathered reptiles we now know as birds. This change resulted from various forces, including natural selection, genetic drift (evolutionary change due to random chance and small population size) and chance mutations that proved beneficial to the individuals that inherited them. The first, ancestral "birds" were pretty much small, feathered dinosaurs. They laid amniotic eggs, but they weren't chickens. Some of their descendants evolved into today's chickens.
So if you want to take the "chicken or egg" question literally, then the egg evolved long before there were any chickens. It was only much later that the first "chicken" popped out of that amniotic egg that had given rise to many other species before.
So there's a longer answer than you probably ever wanted.
So if you want to take the "chicken or egg" question literally, then the egg evolved long before there were any chickens. It was only much later that the first "chicken" popped out of that amniotic egg that had given rise to many other species before.
So there's a longer answer than you probably ever wanted.
