Macroevolution Observed?

From Merriam-Webster online: We have seen species formation, examples of which can be found here and here. Speciation is the only known barrier to evolution. Speciation causes a previously interbreeding group to split into two non-interbreeding groups. This causes different mutations to build up in the separate species, which can only lead to divergent morphology.Macroevolution has been observed, since speciation has been observed. Microevolution, as it is used by scientists, refers to changes within a species, usually adaptive. Change that results in speciation is macroevolution.

Macroevolution is not an event, as Quetzal was trying to communicate. Macroevolution is a point reached by numerous microevolutionary steps. To use an analogy, microevolution is the straw on the camels back, and the straw that breaks the camels back is the macroevolutionary event, or speciation event. To use another analogy, there is an obvious difference between day and night. However, it is hard to determine the exact point where day transfers to night. There is an incremental change from light to dark, but the actual transfer of one into the other is ambiguous.To put it frankly, there is only microevolution. Macroevolution is just the accumulation of microevolution.

Milagros,Let's use some real observations here. The following is from Observed Instances of Speciation These two populations of a once interbreeding population were separated for about 30 years. When brought back together, the two populations were not able to produce offspring. The last sentence from the above quote: "Finally, the Woods Hole population showed slightly different karyotypes from the field populations." The karyotype of a genome is the morphological characteristics of the chromosomes. The Woods Hole group shows different chromosome characteristics, and therefore a change in DNA structure. The reason why both populations did not have this change in chromosome morphology is because they were kept separate. Now, did keeping them separate CAUSE the change in the chromosomes? No, this is due to mutation. Did keeping the populations separate cause this change in chromosomes only to happen in one population? YES. Speciation is caused by changes in the DNA AND breeding isolation. If you only have one of these ingredients, speciation will not occur.The changes in the DNA is macroevolution, since such a drastic change is the cause for speciation in isolated populations. However, it was small, incremental steps (microevolution) that led to the overall differences. Therefore, macroevolution is just the accumulation of microevolutionary events.Does this clear things up? (not meant to be sarcastic, BTW. We really want you to understand where we are coming from).