Anyone who's spent any amount of time in the Creation/Evolution debate knows that a huge problem for Evolution is the persistent absence of transitional forms. In the fossil record, every phylum, without exception, appears fully formed, without evidence of a common ancestor. This supports the Creation orchard, not the Evolutionist tree of life. This was a huge problem in Darwin's eyes. He even went as far as to call it "the most obvious and gravest objection" to Evolution. Evolutionists have come up with several ways to answer this objection, but as we will see, none of them work.
"Every fossil is transitional."
This is actually circular reasoning. To prove Evolution, they need transitional forms, but to assume all fossils are transitional, they need to assume Evolution. When you dig up a fossil, you have a fossil. You don't have a complete ancestral history, you don't have a full list of descendants, you don't even have its age. Thus, you can only believe all fossils are transitional if you already believe Evolution.
Furthermore, this is clearly not how Darwin understood it. Darwin said geology "assuredly does not reveal such a finely graduated chain". If Evolution is true, it should.
"Imperfection of the geological record."
This was Darwin's excuse for the absence of transitional forms. And indeed, in a time when he believed "no organism wholly soft can be preserved", it somewhat held up. But since then, palaeontology has progressed a lot, and we now have fossil representatives of 97% of all living orders of land vertebrates. Of living families of land vertebrates, we have 79% represented by what we currently have. That increases to 87% if you remove birds. Aside from the fact that a lot of them show up in the "wrong" place, that's a pretty big deal. All these fossils, and yet none of them, no matter how they are arranged, form a finely graduated chain, as Darwin predicted. At this point, while it certainly can't be said that the fossil record is perfect, it can be said that the only reason to assume it is imperfect enough that we shouldn't expect these transitional forms to be found is if we assume these transitional forms exist in the first place.
"Punctuated equilibrium."
Punctuated equilibrium is one of many theories designed to make Evolution unfalsifiable. In science, a hypothesis is formed, experiments are done, and the results of those experiments either confirm or refute a theory. In Evolution, an absence of evidence becomes evidence itself.
Punctuated equilibrium is the theory that Evolution generally happens gradually, but every so often occurs in such bursts that no transitional forms should be expected to appear in the fossil record. This answer is unacceptable, because it basically says "there's no evidence because it happened too fast to leave evidence".
"We've found them."
Generally speaking, it is ill advised to say "there are no transitional forms". This is because there are a number of candidates Evolutionists do use in an attempt to rescue Evolution. Thus, a better phrasing is "a handful of questionable examples". Or, to quote Evolutionist Colin Patterson, "there is not one such fossil for which one could make a watertight argument."
This doesn't stop Evolutionists, particularly at the popular level (or higher ranking Evolutionists who think they're speaking to someone uneducated) from trying. Throughout history, a number of "transitional forms" have been presented. Some of them, like Piltdown man, have turned out to be complete frauds. Others, like Nebraska man or Pakicetus, have been based on extremely incomplete fossils filled in by imagination (which often turns out to be just that: Imaginary).
But there are still a handful of fossils that are neither fakes, nor ridiculously incomplete. These fossils are said to be transitional. An excellent example is Tiktaalik. Supposedly ancestral to four legged vertebrates, Tiktaalik has actually been abandoned at the scholarly level due to some fossil footprints supposedly 18 million years older than Tiktaalik. This doesn't stop Evolutionists parading it around to the public, however, which says a lot about the general acceptance of Evolution. Another example is archaeopteryx, supposedly a transition between dinosaurs and birds. Alan Fedducia, a world authority on birds and an Evolutionist himself, said of archaeopteryx "Paleontologists have tried to turn Archaeopteryx into an earth-bound, feathered dinosaur. But it’s not. It is a bird, a perching bird. And no amount of ‘paleobabble’ is going to change that."
To this day, the extreme lack of fossil evidence for Evolution remains a grave objection. It is actually stronger today than it was in Darwin's day, although numerous rescuing devices, such as punctuated equilibrium, have also increased Evolution's resistance to it. Really, this shows the religious nature of Evolution.
By contrast, Creationism explains why the fossil record seems to indicate living organisms originated fully formed, without Evolutionary ancestors. Put simply, it's because they did. God created the heavens and the earth in 6 days, roughly 6,000 years ago, during which time a number of distinct kinds of organisms were created with the ability to bring forth their own kind. That includes human beings.
But the first two human beings, Adam and Eve, sinned against their Creator, and so when they brought forth after their own kinds, they unfortunately passed on their sinful nature as well. But praise be to God, that isn't where He ended the matter. He sent His Son, Jesus, to be born of a virgin, and He lived a sinless life. He was crucified, taking the punishment for our sins. After that, He rose again. If we confess Him as Lord, and have faith in His death and resurrection by God, we can rise with Him into eternal life.