If you are looking for one single item that someone can plop on your
desk, let you look over, and render your verdict, you are misguided.
The evidence for evolution comes from many diverse observations and
experiments -- hundreds of thousands of them at least -- from all over
the world. It is the fact that all of these bits of evidence point at
the same thing that makes the evidence as a whole overwhelming. Here
are just a handful of types of evidence:
1. Life forms show, outwardly, a nested hierarchy pattern. For example,
all ladybugs are beetles, all beetles are insect, all insects are
arthropods, etc. You can verify this yourself by taking a close look at
a thousand or more different species in some moderately sized group (I
have done it with flies) and seeing how they arrange.
This pattern comes from common descent (or deliberate mimicry of it),
and from no other known cause. It does not say anything about the
mechanism, but it does indicate evolutionary change.
2. The same nested hierarchy pattern exists in species' genetic code.
You can verify this yourself (as I have done) by looking at gene
sequences from www.ncbi.nlm.nih.gov
and writing software (or using
existing software packages) to compare them.
3. There are many, many, many transitional fossils, showing changes over
time in fish/tetrapods, hominids, dinosaur/birds, wasps/ants, sirenians,
snakes, titanotheres, ostracods, and more. Even you have to admit that
the evidence is unimpeachable that life has changed -- and changed
radically -- over time. The fossils show that the change follows a
pattern fitting evolutionary change. (Except for casts of hominid
fossils, I have not looked at this primary evidence myself, but all
these are described in detail in journals available in university
libraries and often online.)
4. There has been much basic research showing that mutation and natural
selection are ubiquitous parts of nature. Engineers using evolutionary
algorithms show that when these two combine, evolution is inevitable.
Optimizing changes are the norm, despite complexity.
That is just a sampler. There are also direct observations of evolution
and speciation, reconstruction and replication of evolutionary events
based on genetic analysis, biogeography, coevolutionary evidence, and
more that I don't know much about myself. Still there are two other
types of evidence that are worth considering:
5. There is no better explanation. Most objection to evolution is based
on a belief in some sort of reading of the Bible. Yet we know that the
Bible is not literally true, because the evidence against the literal
Deluge story is overwhelming. (I need not go into detail here because,
judging from your lack of response whenever this is brought up, you
already agree. Besides, I have gone into detail already online in the
Talk.Origins archive.) Now that the religious objection to evolution is
removed, what is left?
Some people also bring up design, but the evidence they bring up for
design (especially complexity and inability to comprehend the mechanism
of change) are far more characteristic of evolution than of design.
6. Evolution has been under sustained, organized, and well-funded attack
for 150 years. There is no way it would still be standing if it were
not supported by overwhelming evidence.
You said you would respond, but I have to wonder why. Evidence is not
something you should pick up or put down on a momentary whim. It takes
time to look it over, check where it came from, see how it fits other
evidence. I spent about five years looking over those flies, for
example, and if you are going to respond to the evidence of fly
morphology, I expect you to put in a substantial amount of time looking
over hundreds of species of flies yourself. Same for all the other
evidence. What, then, are you going to respond to? Are you going to
tacitly admit that you don't care about the evidence, or are you going
to take five years or more to examine the evidence before you address it?
Mark Isaak eciton (at) curioustaxonomy (dot) net
"It is certain, from experience, that the smallest grain of natural
honesty and benevolence has more effect on men's conduct, than the most
pompous views suggested by theological theories and systems." - D. Hume