O.K.
You've been misled about that. For example, Hall observed the evolution of a new, irreducibly complex enzyme system in a culture of bacteria by natural selection and random mutation. Speciation has been directly observed. Would you like to learn more about it?
So what step between say, reptiles and mammals do you suppose could not have come about by gradual change? Let's see what you have to show us.
I'm thinking it's that you don't know what Darwinian evolution is. You should know, BTW, that the evolutionary theory accepted today is modified by the findings of genetics. Interestingly, Mendel's discovery of genes cleared up a real problem for Darwinian evolution. Would you like to learn about that?
But first, just so we know you know, how about telling us Darwin's four points of evolutionary theory? Which of them do you think are not observed?
While Darwin's four points remain as solid as ever, genetics has changed the theory significantly. If you want to argue against evolutionary theory, you should at least know what it is.
As you might be starting to suspect, common descent isn't part of evolutionary theory. It's a consequence of evolution. But remember, modern evolutionary theory is not classic Darwinian theory.
That's the hard part for creationists. If you want to talk about "modern evolutionary theory", you have to know what it is.
Darwin's main points are still firmly established, but the modern theory includes Mendel's discovery of the mechanism of heredity. Creationism's conflation of the two is intentional, and you demonstrate the very reason why I make the distinction - all the ambiguity and equivocation that comes with creationist's use of the word "evolution".
That's pretty much your position, so far. So do you want to talk about Darwinian theory, or the Modern Synthesis, that includes genetics?
And the second step, and the third, and the fourth... Speciation doesn't stop. Populations continue to evolve and sometimes, give rise to even more different new species.
That's about it.
The creationist argument is like the man who says that it's possible for a human to walk one hundred yards, but it's impossible to walk 50 miles.
That's what it is. "Microevolution" is evolution within a species. "Macroevolution" is the evolution of new taxa.
Much like driving to the edge of your town is an astronomically small part in the process of driving across the country. The key is in understanding that the process works the same way, no matter how far you drive.
Turns out that you're wrong...
CHICAGO (Reuters) - The discovery of a “frogamander,” a 290 million-year-old fossil that links modern frogs and salamanders, may resolve a longstanding debate about amphibian ancestry, Canadian scientists said on Wednesday.
https://www.reuters.com/article/us-...over-frogamander-fossil-idUSN2134298920080522
Actually, that's what we've observed to happen. New species. That's what macroevolution is.
Random mutation and natural selection. Usually. There can be speciation by random change in small populations, but it usually leads to nothing new.
As you now realize, the evidence shows that is how it happens.
Sorry, that idea won't work. Without evolution, as we see it happening, common descent would not be possible. If you find that difficult to understand, we can talk about it further. But I think if you thought about it for a while, you'd see shy.
Which fits nicely into a family tree, as Linnaeus first noted. (he didn't have any idea why) Later, when we learned about genetics, scientists predicted that genes would show us the same family tree. Turns out it does to a very high level of precision. And we know it demonstrates common descent, because we can test it on organisms of known descent.
A change in allele frequencies in a population over time. Or more simply, "descent with modification." The former, as I explained earlier, includes the modern theory which includes genetics.
Of course. And as the process continues, populations diverge and become more and more different. Most professional creationists now admit the evolution of new species, genera, and families. If they retreat just a little farther, we won't have anything to argue about.
If you can walk on water, then I suppose so. It's like arguing that giant redwood trees can't grow to adulthood from a seed, because no one has ever seen it happen. Such arguments contain their own seeds of failure. Pointless to even bring them up.
Let me go try.
Change in allele frequency in a population over time.
Yep. I've been considering that for over half a century now. The biggest obstacle was from prokaryotes to eukaryotes. Must have been a real challenge. Took about a billion years, given the fossil record. The likely process was endosymbiosis. Would you like to learn about the evidence for that? Or any other step in the process, if you like. What would you like to talk about?
How about a mutation that allows the brain to be more resistant to cancer during radiation therapy?
Radiation Oncology 2012 Oct 30;7:181
EGFR mutations are associated with favorable intracranial response and progression-free survival following brain irradiation in non-small cell lung cancer patients with brain metastases.
Lee HL1, Chung TS, Ting LL, Tsai JT, Chen SW, Chiou JF, Leung HW, Liu HE.
Neuro-oncology
Volume 12
November 2010
Nineteen (20%) patients had solitary BM with no sites of extracranial metastatic disease at the time of brain involvement; this was significantly more common in patients with EGFR wild-type tumors (31% vs 7%, P = .03). In EGFR-mutant patients, active systemic disease was very common at the time of BM, with 83% of patients having either new or progressive disease outside of the brain within 1 month of BM diagnosis. In EGFR wild-type patients, this proportion was significantly lower (62%, P = .001).
April F. Eichler Kristopher T. Kahle Daphne L. Wang Victoria A. Joshi Henning Willers Jeffrey A. Engelman Thomas J. Lynch Lecia V. Sequist
Tetrachromats. A very few humans have a mutation that wires eyes and brain to have four primary colors, rather than three. In vertebrates, the retina is part of the brain.
https://pdfs.semanticscholar.org/313c/ebb88197fba22a2ec96fdcea9171395268da.pdf
Yep. The bad ones tend to be removed, and only the good ones tend to increase in a population. That's the point. Random mutation and natural selection. How else would it work?
As you just learned, it requires random mutations and natural selection.
If you'd set your pride aside, for a bit, you might be more successful. Most scientists who are believers are more humble than you seem to be.
Of course. Biologists just know a little more about the details than you do.
It's worth pointing out that Huxley won a debate with Owen, by showing him that a chimpanzee has the same brain structures as a human, only differing in size and somewhat in shape.
So it's more subtle than you seem to think it is.