The first thing we have to understand about fossils is that they are rare. The conditions necessary for fossilization have to be so exact that the chances of an organism ever actually becoming fossilized are extremely small. This explains why there are gaps in the record: not every organism fossilizes.
The other thing we have to know about fossils is that all fossils are transitional fossils (in some way). All of the fossils ever discovered show some kind of transition between their ancestors and their descendants. Now, this is an extreme generalization, but it necessary to understand that transitional fossils exist everywhere in the fossil record.
So, what is a transitional fossil NOT. Many creationists define a transitional fossil as a fossil that shows a combination of traits from one species and another. This is why they think we don't have any at all: they're looking for a crocoduck.Now, what we are really talking about when we say "transitional fossils" are specific links between organisms, such as the link between water dwelling organisms and land dwelling organisms, or the link between ape and man. But, you have to understand that transitional fossils are not hybrids of specific organisms, but rather just a fossil that shows a mixture of features between older organisms and newer organisms.
Heres some examples:
- Titanotheres, who went extinct in the Cenzoic era. We have fossils which show the progressive increase in the size of their horns from small to large. We've also seen the development of certain head and neck features which are similar to those used by rams.
- The species Globigernoides trilobus and Orbulina universa have a wide variety of fossils showing the development of certain morphological traits.
- We have fossils showing the developments between certain species of Phacops.
- There is a 2 million year old record of development of the diatom Rhizosolenia.
- Lake Turkana molluscs
- Cenzoic era marine ostracodes
- The primate genus Cantius
- A 13 million year old record of the gradual changes of the Scallop genus Chesapecten.
- Gryphaea, which become broader and thinner during the Jurassic.
- Australopithecus shows the changes in the pelvic girdle and other features that show the transition between knuckle walking and walking upright.
- Fossils showing the transitions between dinosaurs and birds.
- Haasiophis terrasanctus, a marine snake that has limbs. Shows the transition between limbed to limbless snakes.
- Jaws of mososaurs show the transition between snakes and lizards.
- Fossils that show the transition between mesonychids and whales.
- Fossils that show the transition between fish and tetrapods.
- Fossils that show Condylarth to manatee transitions.
- Runcaria, the precursor to seed plants, which has some of the features of modern seed plants missing.
- Melittosphex burmensis, which shows the transition between some kinds of wasps and bees.
This is just breaking the surface. Despite their rarity, we have a lot of fossils which have transitional features.
Some other smaller claims made by the Answers in Genesis with regards to this myth are that fossils don't tell us who it's ancestors or descendants are, or even how it used the body parts it had. In reality, of course they do. By grouping together fossils with similar structures, dating them, and studying what modern species with those structures do with them, we can build an accurate picture of the ancient world. Fossils don't tell us directly, but the science of Paleontology does.