The Theory of Evolution: Evolving!

Medopine

This is a thread about theories of evolution as it relates to biology, that is, the origins and development of life. I would like to discuss theories of evolution and how they differ, what kind of scientific evidence they rely on, and so forth. This discussion idea stems from a recent conversation with someone I know who is skeptical of evolution as a widely accepted and rarely questioned theory. Her points are spoilered below and you may choose to respond to them if you wish as a jumping off point:

- It's not good science to form a theory of evolution and then go looking for the evidence. You should have evidence to base a theory on to start with.

- "Graduated evolution" isn't a good theory because there is not enough evidence, specifically not enough intermediary forms have been found (when asked about Archeopteryx, she expressed skepticism as to that famous fossil's authenticity)

- No one can talk about evolution critically because if you question the theory you are immediately thrown into the camp of the creationists

- If forced to choose a current theory, she would choose Punctuated equilibrium over "graduated evolution"

More generally, some questions:

• Is there a unified or widely accepted model for evolution within the scientific community?
• Is evolution a fact or a theory? Is it both?
• What are the problems with our theories of evolution?
• What is the concrete scientific evidence for the theory? How has the theory been tested and proven?

Basically, I'd like to hear what people know about evolution and really get into specifics as to how it works. Also I'd like to hear about any sort of alternative theories or differences in the scientific community that exist (for example punctuated equilibrium evolution). Additionally, we can discuss the problems with finding scientific evidence through a fossil record that is inherently going to be incomplete and sometimes insufficient. Drifting into geology might be acceptable here.


Please do not

- Talk about why religion is bad
- Talk about how creationists are stupid or intelligent design supporters are stupid
- Talk about religion at all, really
- Also please let's not talk about evolutionary psychology please please

I know this will be terribly terribly hard to do, but maybe we try hard, yes? I'm looking to talk about evolution and discuss possible scientific criticisms of the theory. Let's do it!

Incenjucar

The main issue with evolutionary theory that I've noticed, as a semi-layman, is the usual tendency of people to try and create singular models for something that can have a great deal of variation, in some misguided attempt to create a simple formulaic method from something which is two parts random and three parts way-too-many-factors-to-measure.

Evolution is going to happen at the pace that happens to work, not in some predictable wavelength.

It's entirely possible for, say, a niche to become suddenly vacant and for no local creatures to happen to develop the mutations that would allow them to take over that niche. It's possible for this to NEVER HAPPEN before the sun envelops the planet. It's possible for it to happen entirely because this one bird took a crap on the wrong butterfly and bam, end of the first step in insectoid unicorns with eye rays, which is never again possible, ever.