What I've found difficult is evolution will have a missing link fossil found proclaim it to the world fit it nicely in their graph and then if it turns up as a living fossil swimming around the ocean they try and explain only part of it's group went on to form a new group/species while the others stayed the same for millions of years.
OK so this is easy, the "missing link" that people are talking about is based on transitional fossils. For instance a Scientist finds three fossils, one with a nose at the end of a snout, one with the nose at the forehead, finally one on top of the head (which would now be a blowhole). So they're missing that second fossil that has a nose in the middle of the face, before the forehead but above the snout. Science makes a prediction that there will be an organism with this change, hence they're looking for a "missing link". They can predict the time frame it would've lived in, the general strata where it would be, etc. You might want to look at the sheer enormous list of transitional fossils to see that for the most part the "missing link" they're looking for are found. As to why only part of the species adapted is because it's through mutation. Let's say some change occured in our environment that gave people with six fingers a better chance at survival. We know that this mutation occurs occasionally but serves no real benefit, however if it did serve a benefit then people with this mutation would survive in greater numbers than those who didn't. Not to say the others would've survive, but eventually if the attribute was that great, then you would see only six fingered humans surviving. Then someone would look for a missing link between the five fingered and six fingered humans.
Evolution is post predictive they fit the finds to the theory concentrating on what fits ignoring what doesn't, Its just an alternative to faith in God in this case it's faith in creation itself, mother earth it's old religion, time is evolutionists God they say throw enough time at a thing it will change and of course you gotta learn all your ...illion words to sound authentic.
You might want to check on this, it actually is not post-predictive. There's an article on panda's thumb about a scientist predicting where he would find a missing link for a specific animal (which escapes me now) and for years they couldn't find it. About 4 years ago they did. Evolution does not at all dismiss what doesn't fit, you're explaining creationism there. Explain how Chromosome 2 shows the extra telomeres that are evident in a merged chromosome? The thing is there's no faith in evolution, it's totally falsifyable. Please go to pubmed.com and check out the genome sequencing to see how the endrogenous retroviruses match up to the fossil record which matches up biological phylogenetic trees. If it wasn't falsifyable they would not match up the way they do. Please research it, you'll see the jaw dropping amount of evidence in favor of evolution.