This post is to offer solutions to a question I keep seeing brought up on the forums. "Where are these missing transitional forms?"
It's true that in the fossil record we will frequently find an example of a species, then a few layers higher we'll find a changed version of that same species, but be unable to find fossils for the in between steps.
Hopefully, the scenario I lay out here will help explain how this could happen.
Here's a scenario:
Imagine a species of rodent, very successful, which spreads over all the connected land masses and even manages to get on a few islands.
The fact that it's so wide spread helps insure that it is likely to survive as a species for a very long time. However, changes in one member of the species would have trouble spreading to every other member just given their huge numbers and geographic distance.
As a result this species may be "stable" in the fossil record for a long time, seeming to not change much at all.
But remember those islands the rodent also got to? Changes in an individual living on one of the islands could more easily effect that much small population and it's smaller geographic range.
Time passes, and as it does, on one of the islands, the rodent population changes significantly as a result of random mutation and pressures put on them by the islands specific hardships (tough skinned fruits, predatory birds, etc). Let's say the island rodents get bigger, develop a shorter tail and stronger front legs (just picking features at random).
Meanwhile, everywhere else in the world, the rodent populations in different regions also change, but much less dramatically.
If you were to find a fossil at random from anywhere in the world, chances are it would be from an area other than on this one particular island. You would find an individual looking very much like all the rest of the rodents.
Then, one day, a storm comes through, knocks a bunch of trees over on the island and washes a couple dozen of the bigger badder rodents out to sea.
They come ashore, and the world around them is completely unprepared.
The predators that normally feed on the smaller rodents, can't handle these big ones. Food the smaller rodents couldn't reach is readily available to their cousins longer limbs. Etc.
Given the room to spread out, these island rodents reproduce like wildfire, spreading over the same territory the same way their ancestors did centuries before.
The smaller rodents, unable to handle the competition are quickly replaced.
The fossil record from random location X would show little rodent, then big rodent, but it would not show a transitional step between the two. There wouldn't be a fossil for big rodent with normal front legs, or long front leg rodent with normal tail. At this location, like 99.99% of the others, there would simply be little rodent, then big rodent.
If you were looking specifically at the fossil record of this particular island, and if fossils had actually managed to be created there (small chance to begin with) you'ld find these missing links.
This is obviously not the case for every single species, but I hope it helps explain why you may see a seemingly rapid jump between step 6 and step 9 in a chain with no apparent examples of steps 7 or 8.