Thats fantastic thanks for that, Strega
Evolution couldn't be anything other than gradual. You simply can't go, with the flick of a switch, from say, a simple thing like a bacteria to a complex thing like a human or an elephant. That's why creationism is the equivalent of pulling the rabbit out of the hat. Evolution is gradual because genetic changes accumulate glacially over millions and billions of years giving rise to all of the complexity of the natural world.
Richard Dawkins put it very well and eloquently in his book Climbing Mount Improbable (which I highly recommend).
Evolution is not smooth. Change in species is a response to change in environmental conditions. Environmental conditions can stay the same for long periods of time, but they can sometimes change relatively suddenly. That's what I understand from reading The Selfish Gene. Makes sense to me.
Yes. These somewhat famous worms represent a fairly recent example of such environmental change and pressure: http://news.nationalgeographic.com/news/2008/10/081007-super-worms....
Here is a bit of real time evidence for evolution ...
"A new paper in Current Biology by Charles & Mary Brown with the folksy title, “Where has all the road kill gone?“ reports evidence for rapid evolution of wing length in cliff swallows (Petrochelidon pyrrhonota) nesting on highway overpasses in Nebraska. (See also this news piece on Science‘s website.) For those evolution-deniers who demand to see natural selection in “real time,” this is one bit of evidence. .... cont
and Ive always loved this very simple explanation of the evolution of the eye by Richard Dawkins. If I can understand it - anyone can.
There is scientific consensus that the capacity to synthesize nylonase most probably developed as a single-step mutation that survived because it improved the fitness of the bacteria possessing the mutation. This is seen as a good example of evolution through mutation and natural selection that has been observed as it occurs.
** Use debate as an opportunity to learn about modern evolutionary theory
Really, there is no point to talking with xians on evolution except to remind them no one needs to take science on faith -- xians do not live in a fact-based reality. They imagine that texts must be the final court of appeal -- this is their profound misunderstanding.
Science isn't about texts, or exigesis of texts. Textbooks in biology are for training students in the fundamentals of theory and *experimentation* -- they are not on the forefront of current knowledge or research -- far from it. You haven't even begun an apprenticeship in the science of biology with a bio undergraduate degree in hand. That's just a given in any modern science.
Any idiot can be a theologian -- or a preacher or an evangelist or an imam -- their views are not rooted in reality but in cash-making institutions providing comforting fairy tales to eternal adolescents, as in Peter Pan they never grow up -- along with big doses of social control known as "the enforcement of morals."
Ok ... to your request --- I'd start out by going to Wikipedia -- search Steven Jay Gould. Look under 'punctuated equilibria' -- Gould did not think that evolutionary processes were incremental -- gradual, as Darwin had claimed.
The basic view behind punctuated equilibria gets based on population genetics -- which shows that only in isolated relatively small (5,000+ individuals) populations do mutations have an opportunity to be spread successfully. Thus, speciation is (geologically speaking) rapid --
-- hence speciation eveents are more like points (puncta) in time compared with longer times during which large, freely interbreeding species show no great tendency to speciate -- hence they are in equilibrium giving rise to a false, because limited time perspective xians mistake for god's one-and-done act in Genesis.
The writers of so-called sacred texts -- had no sense whatsoever of what we call 'deep time' -- and, of course, many xians want to throw out deep time thinking that will destroy natural selection -- the young Earth crowd of IDiots.
If it helps any -- remember xians want to argue about texts -- for them Darwin's work represents a "sacred" text of biology. Darwin is honored, not because he found some dogma about speciation to spread as a form of faith.
He recognized that what look like design and purpose in nature could be explained without reference to any "life force", "spirit", "metaphysical plan" -- descent through modification by natural selection -- as Darwin called evolution is not godless since there is no god; but god free because the god hypothesis dropped out of any meaningful biological theory.
You can put all the facts in front of them and they will still tell you to prove to them.
Ain't that the truth.