Taking this one separately, Bex, for clarity:

Quote
Would you please provide the same to prove evolution? Something observable and testable/repeatable....
There are many ways that evolution can be observed, tested and validated. When it is observed it is a fact, and the evolution in that instance is proven by that occurrence.

When the finches on the Galapagos Islands changed from small beaks to large beaks and back again, this was the change in hereditary traits in populations from generation to generation, which is evolution. Thus evolution occurred in those populations of finches.

There are a number of experiments you can do with bacteria that show similar changes in hereditary traits in populations from generation to generation.

One from another site ("lawn" is a growth of bacteria on a medium that spreads out and covers the medium, usually in a petri dish):
Originally Posted by Rrhain on another site
Here's an experiment you can do in the privacy of your own bio lab. It doesn't cost much and you can get the materials from any reputable biological supply house.

Take a single E. coli bacterium of K-type. This means the bacterium is susceptible to T4 phage. Let this bacterium reproduce until it forms a lawn. Then, infect the lawn with T4 phage.

What do we expect to happen? That's right, plaques should start to form and, eventually, the entire lawn will die. After all, every single bacterium in the lawn is descended from a single ancestor, so if the ancestor is susceptible, then all the offspring should be susceptible, too.

But what we actually see is that some colonies of bacteria in the lawn are not affected by the phage.

How can this be? Again, the entire lawn is descended from a single ancestor. They should all behave identically. If one is susceptible, then they're all susceptible. If one is immune, then they're all immune. This can't be an example of "adaptation" because if one could do it, they all could do it.

But since there is a discrepancy, we are left with only one conclusion: The bacteria evolved. There must be a genetic difference between the bacteria that are surviving and those that died.

Indeed, we call the new bacteria K-4 because they are immune to T4 phage.

But we're not done. Take a single K-4 bacterium and repeat the process: Let it reproduce to form a lawn and then infect the lawn with T4 phage.

What do we expect to happen? That's right: Absolutely nothing. All of the bacteria are descended from a single ancestor that is immune to T4 phage. Therefore, they all should survive and we shouldn't see any plaques form.

But we do. Plaques do, indeed start to form. How can this be? Again, all the bacteria in the lawn are descended from a single ancestor that was immune to T4 phage, so they should all behave identically. If one is immune, then all are immune. There must be something else going on.

Something evolved, but the question is what. What evolved? Could it be the bacteria experiencing a reversion mutation back to K-type? No, that can't be it. Suppose any given bacteria did revert back to wild. It is surrounded by K-4 type who are immune to T4 phage. As soon as the lawn is infected, those few bacteria will die and immediately be replaced by the offspring of the immune K-4 bacteria. We would never see any plaques forming because the immune bacteria keep filling in any holes that appear.

So if it isn't the bacteria that evolved, it must be the phage. And, indeed, we call the new phage T4h as it has evolved a new host specificity.
... And then we have the similar experiments that Russel2 mentioned earlier.

There are literally thousands of lab experiments where evolution has been observed and documented, and there have been hundreds of instances where it has been observed and documented in the wild, from the introduction of a new variety (new hereditary trait) up to and including the development of a new species. If you want to develop a new species you will need to dedicate a few years to the process (as evolutionary biologists have done), but if all you want is an instance of evolution, then the above experiment fills the bill.

You can also look at any generation and measure the number and frequency of hereditary traits in a population, and then measure them in a later generation of the same population.

You, likely, will reply that all this is just microevolution, and that this is nothing special, that creationists agree with microevolution.

Many creationists will claim that this is not "real" evolution ... however, what they, or anyone else, thinks is evolution is irrelevant if it does not match the definitions used in science: evolution is the change in hereditary traits in populations from generation to generation. That is what evolution is and that is how it is measured and observed and tested.

And when you have run an experiment, or made an observation in the field, where you confirm that the hereditary traits in a population have changed from one generation to another, then you have proven that evolution has occurred.

And setting up a lab experiment like this is no more difficult than canning (the same degree of sterile control is used).

Enjoy.