Bart,
I teach college Biology, so let me tell you how scientists explain the 'common ancestor' theory in evolution.
 
It begins with DNA: this genetic material consists of a phosphate sugar backbone with four nitrogenous bases
(A, C, G, T) which spell out a 'code'.  The genetic code (ATGACCAGATTC) is a set of instructions on how
to make you with five fingers, blue eyes, curly hair, etc.
 
DNA is a common component of every living organism on earth: plants, animals, fungi, bacteria and one-celled
pond critters.   While the code between organisms is different, the structure of the DNA itself is identical:
sugar-phosphate backbone with 4 bases: A,C,G and T.
 
This implies that life evolved only once on this planet and all living organisms share a common ancestor.
As living organisms went through the process of evolution, greater variation in the DNA code became evident.
The 'intelligent design'crowd should consider the following facts;
 
There is less than 3% difference between the DNA code for a human being and the DNA code for a chimpanzee.
25% of the genes in a human are identical to those found in a banana.
 
ha ha

Can we prove there was a common ancestor, no.  Can we take what we know, gather evidence and form a theory
referred to as evolution, yes.
 
Biologists aren't asking Christians to give up their religion and Christians shouldn't ask Biologists to give up their science.
If they want to take a Theology course, fine.  But I teach Biology, not religion and the 'intelligent design' crowd should
understand that when they sign up for one of my courses.
 
Becky

 Subject: answer for Jitske - how things evolve

What hogwash. There are lots of books that describe in excruciating
detail exactly how things evolve.

I had to field this question once from a really nice guy who was
sailing my wife and I around a harbor. I'd never him, but he knew I
did basic research in drug discovery. He started off our two-hour
cruise with, "So when have you ever seen evidence of evolution?" Ack.
A staunch creationist at the helm.

I was able to look at my watch and honestly answer, "about 36 hours ago."

Part of the ongoing war against those nasty drug-resistant bacteria is
figuring out how they actually do become resistant to the drugs in the
first place. It's pretty simple. You plant a few billion of them on
food that contains the drug, and then you look at who survives. Those
bacteria that make it usually have a very specific mutation in some
gene that allows them to dodge the bullet. Nowadays, pulling out that
exact mutation can take as little as four or five hours in a lab.

Challenge, mutation, survival, procreation. That's evolution.

As to exactly how, again that's been deeply explored. Your DNA is
always getting mutations. It's just a fact of life. Sunlight,
chemicals, faulty machinery in your cells - there are all sorts of
causes, well-characterized down to the basic chemistry. A lot of those
mutations get repaired, again by well-characterized enzymes. A lot of
them don't, but they don't really hurt you. And then, every once in a
while, one actually helps. Like letting you survive an antibiotic to
beget a gazillion more bacteria. All your offspring carry that new and
improved gene, and thus are "evolved". There are literally thousands
of journal articles with rigorously researched examples.

It's really just that easy. The cruise went four hours instead of two
because we got so into it (malaria & sickle cell, those silly beetles,
God and stuff, etc.). It was a great discussion, a lot of fun,
although in the end neither of us were really swayed by the other's
arguments. It almost always boils down to faith vs. science...

Earl

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