Heritable changes spread over many generations and any change in the frequency of alleles within a gene pool from one generation to the next, mean the same thing....Its simply two different ways of saying it.



Sorry to disappoint, but it is how evolution works. By small changes over time. I know its much more fantastic to envision a lizard laying eggs and chickens hatching -But all the evidence accumulated in biology thus far points to slow subsequent changes or "allele frequencies changing from generation to the next".



This is what I posted about in the beginning of this topic. It was back when you had disappeared for a while so maybe you missed it and did not wish to read the whole topic. Back on page 2, post 22 I used the analogy of a color bar for generations for a lineage. Though, some felt it a poor analogy I think it works well. Because the change to each color is very small -The same for a new generation of a population. When one species stops and the next one starts is indistinguishable -Unless of course we call every generation a species, which you could make a case for that too.

Remember Yeti, species are simply arbitrary groups we assign to natural populations. They are not in any sense real tangible things.




Who said its violating rules? I think your missing it still (what I tried to illustrate with the pictures). Both of those picture groups above (birds and cichlids) are each different species. Though the look almost identical. The two species of wood peckers are so close looking -morphologically that you would need to be a bird expert or a geneticist to tell them apart. Let's call the woodpecker on top W1 and the bottom one W2. And let's for example say W1 is the ancestor to W2, they are both different species -but the changes between them are extremely small. Just the same with the chickens and almost, but not quite-chickens. W1 is almost, but not quite W2.

Follow now?



What are you talking about "scientific evolution" just handled the question.......Besides modern chickens were domesticated by man in Thailand. That is the are a man made species. All modern chickens descend from a subspecies of Red Jungle Fowl. Behold the chicken ancestor:

Like I said, Almost, but not quite-chicken.

Behold the chicken


See handled.

This is why we needed to correctly define species. Your definition:
A group of closely related organisms capable of reproducing

Is inadequate because it is not specific and fails to account for many organism. For instance, lions and tigers are closely related and are capable of producing offspring -Are they the same species? By your definition they are.

I would argue they are not the same species.

The text book definition you provided:
The species must be regarded as an interbreeding population made up of individuals of common descent and sharing intergrading characteristics.

In which case the lions and tigers are not the same species nor are the cichlids. Many things are capable of breeding -But simply being capable is not enough to define species with. We must base it on mechanisms of reproductive isolation or as your author says "interbreeding populations". That is in the wild are they actually interbreeding?

There are many mechanisms that lend to reproductive isolation both prezygotic and postzygotic mechanism. For example:

Geographical or ecological, the populations live in the same regions but occupy different habitats.
Seasonal or Temporal, the populations live in same regions but are sexually mature at different times.
Behavioral, populations are isolated by different and incompatible premating behaviors.
Mechanical, fertilization is prevented by differences in reproductive structures.

and on, and on, and on.

Using your above diffention of species. A Liger half tiger and half lion. One of the sexes is able to breed the other isn't. So does this make tigers and lions the same species or not.

As usual you bring up some good points and no one can compete with your hot picture posting skills. Your point stands about clarifying definitions. I think you will acknowledge the time factor difference in generation(s) and generation. Even within one generation there is time factor. Say, elephants and fruit flies.

As far as cichlids - all the mbuna can reproduce fertile offspring. You'll see difference in color, but they're the same species. As far as lions and tigers - my understanding is that while artficial selection can produce a liger; the offspring are infertlile.

As far as I know you can't cross a South American and African cichlid.

I'm going to see if Destination Truth can prove the existence of the yeti. Good night.

Considering chickens came from red jungle fowl (as Copasetic noted) and they are birds which came from therapods which layed eggs, I would say the egg came first.

No because male ligers are always infertile.

Several thoughts: First, the events you are describing are not random. This will at least distort and may completely demolish probability calculations based on the assumption of randomness.

Second, there are billions of viable genetic combinations. With the exception of clones, every one of us is a unique combination of genes and so is every living organism. The probability that a particular combination will occur is orders of magnitude lower than the probability that any of billions of possible combinations will occur.

Third, the probabilities cited by creationists are for the occurrence of a given combination occurring on the first trial. But the number of trials occurring at any given instant are in the trillions and we have a time span in the hundreds of millions of years for the repetition of each of those trials.

Fourth, probability estimates are based on (a.) homoscedasticity - the assumption that the variance of your estimate is the same everywhere in the range of values you are dealing with; (b.) existence - the event you are describing must be physically possible; (c.) independence - the outcome of one trial has no effect on the outcome of other trials; and (d.) linearity - the relationships you are trying to describe must exist in nature and not just as an artifact of the investigative process. Violate one of those assumptions and your results are open to question.

The "miracle" is not that life arises spontaneously; it would be a miracle if life, under favorable conditions, did not arise.
Doug