1. Mutations only alter existing information, it doesn't create new informations
A common argument put fourt by creationists is that mutations can't create new information, they only modify existing information. A common example put fourth showing that evolution happens is that bacteria evolved the capacity to digest nylon using an enzyme known as nylonase that arose from a mutation. Creationists will say that it doesn't count because it's merely a modification of an existing enzyme knows as an estherase. But the problem with this argument is that any modification to existing information is NEW information and the nylonase enzyme, even though it arose from an existing enzyme is still a new enzyme with a new function. It's the sum of these small and incremental changes that have produced every major change that creationists say that evolution could not have produced is the sum of small and incremental changes, a topic that we'll explore later in this take.
2. The law of entropy prohibits evolution
A common argument put fourth by creationsists is that the second law of thermodynamics prohibits evolution because in evolution, everything is going from disorder to order while the second law states that everything goes from order to disorder. However, this shows a complete lack of understanding of how entropy actually works. To illustrate why everything seems to go from order to disorder, I have two 10x10 grids pictures above. One was randomly filled in with various colors and the other I put a specific pattern on. So, looking at probability alone, which one of these specific patterns is more likley to occur if someone else randomly filled in the colors. It's a trick question; they're both equally improbable. Given that I had 20 possible colors to chose from the chance of any one configuration is 1/(20^100). So in any given system that odds of any one configuration are almost infinatley improbable, but ultimatley the system must exist as a state. The only reason for the apparent trend from order to disorder is that the total number of states we'd recongize as disordered outnumber the states recognized as ordered. So there is no magic force making everything going from order to disorder. It is true that in the universe there is a net trend from order to disorder but that doesn't mean that every system has to go from order to disorder. It all comes down to what is most thermodynamically favorable.
3. Microevolution is possible but not macroevolution
In spite of the many documented examples of evolution by natural selection that have occured, creationsts will say that it doesn't count because it's just microevolution. Well what is the difference between micro and macroevlution. Well the best definition available is that microevolution is evolution below the species level and macroevolution is evolution above the species level. Now what exactly is a species? Well simply put to be part of the same species two organisms would have to breed and produce fertil offspring. If they can reproduce but produce sterile offspring, they will usually be considered to be part of the same genus but of different species. And, guess what, there are at least 30 observed instances of populations becoming reproductivley isolated from one another which is the definition of macroevolution. In order for this to be true there would have to be two distinct kinds of DNA, one that is responsible for variation below the species level that is susceptible to mutations and one that is common to every member of a species that is not susceptible to mutations. However, there are no two such kinds of DNA. Many creationstis will say that even though speciation has been observed, evolution can still only produce change within certain boundaries and that no lineage of organism can be traced beyond its alleged original archetype. However, they are consistantly unwilling to say what these archetypes are or how they could be recognized or describe where these boundaries are.
4. Organisms only give birth after their own kind
A common argument put fourth by creationsists is that organisms only give rise to their own "kind" and even when presented with clear cases of speciation (macroevolution) they still say that it doesn't count because if say a new species of fly was observed to evolve, they would say that it doesn't count because it's still a fly and not a beetle or something like that. Well this shows a basic misunderstanding of one of the basic principals of evolution called the law of monophyly. This law states that organisms never outgrow their ancestry and every species that ever existed is simply a modified version of what came before it. You start off with organsims A which evolves branches off into two species B and C. Both species B and C will be part of the same clade which we'll call A' due to their descent from organism A. But then B evolves into species D and E and C evolves into F and G. D and E will form a new clade which we'll call B'' and F and G will comprise the clade C'' because of their cammon ancestor with C. However no decendants of F or G will ever become members of clade B' because B' reperesents an independantly derrived lineage and D,E,F and G and all of their descendants will still be part of clade A' because of their descent from organism A and Clade A' would include clades B'' and C''. For example, creationists will say that there are many species of dogs, but they're all still dogs, they don't become cats; well of course they won't!!! Cats (felidae) are an independantly derrived lineage of animals so a dog becoming a cat would violate this principal. Any organism that evolved from a living species of dog will still be a dog and any species that evolved from a species of cat will still be a cat. But lets look deeper into this. Dogs and cats both belong to the order carnivora which includes most of the major mammalian land predators such as (obviously cats and dogs) weasels, raccoons, bears, hyenas, mongooses and even marine predators like the seals. Each of these independantly derrived lineages arose from the common ancestor of the order carnivora and the carnivora as a whole is much more morphologically diverse then any of the families that it includes because the common ancestor of carnivora lived a much longer time ago than any of the common ancestors of the afforementioned families. And any future species derrived from any of the afforementioned families (i.e. a new species of dog) will always be a member of both the canid and carnivoran clades. It won't evolve into another independantly derrived clade within the carnivoran collective (such as a cat) nor will it evolve into another clade that is not derrived from the carnivoran clade (such as an elephant). Looking the other way, the more and more you look back in time the more and more the different lineages of the order Carnivora will resemble each other and the common ancestor of all carnivorans. If you don't beleive me, lets again take the classic example of dogs and cats. There are two main branches in the order carnivora: the dog branch (caniformes) which includes dogs, bears, seals, weasels, raccoons and skunks while the other branch (feliformes) includes cats, hyenas, mongooses, meerkats, civets and genets. To illustrate the law of monphyly, Below is a side-by side image of a leopard and a wolf. At first glance it may hard to beleive that they share a common ancestor.
But below is a side by side image of a grey fox and a domestic cat. Clearly the grey fox has many similarities with the wolf and the cat has many similarites with the leopard, but the cat and the fox share some resemblance with each other albeit not as much as they share with the wolf and the leopard. This is because both closely resembles the common ancestor of all canids and felids which itself would have more closley resembled the common ancestor of the order carnivora hence the apparent similarities.
We can take this a step further and look at the most basal caniforms and feliforms in existance. The most basal caniform is the ring tailed cat (which isn't a cat, it's a member of the raccoon family) and the the most basal feliforms are the civets and genets. The ring-tailed cat bears some resemblance to the fox and the genet bears some resembelance to the cat but, despite the ring-tailed cat being more closely related to a fox and the genet being more closely related to the cat, they more closely resemble each other than they do to either the cat or the fox. This is because neither has changed much since having evolved from the common ancestor of both caniforms and feliforms which itself had just evolved from the common ancestor of all carnivorans. Thus, these two species, even though they're as distantly related to each other as wolves are to leopards bear a close resemblance to one another.
If you were to look at all the speices of carnivorans that lived 45mya they would have had as much morphological diversity as foxes do today. In this group of animals you would have the species that would give rise to the various species of carnivorans that we see today and even though each one would have looked more like a ring-tailed cat or a genet than any of their descendants, you would began to see the definitive traits charecteristic of the family that they would give rise to from this original template. But just as creationists today would argue that today that if a new species of dog was documented it wouldn't count becaus it was still a dog they would argue that the common ancestor or the carnivorans evolving into the various different species that would give rise to the different groups of carnivorans such as hyenas, weasels, skunks etc. doesn't count because they're still carnivorans and the change the single incrament isn't enough to prove evolution, and going down the lineage they would say this about each individual incrament down the lineages until you got down to either a cat or a dog. Yet it's the sum of these small incramental changest that creationists claim are "too small" to count as macroevolution that comprise even the most profound changes in evolution (such as a fish like animal to a bird or mammal).
5. If we evolved from apes, why are there still apes
Another cammon and equally fallacious argument put fourth by creationsists is that if we evolved from apes, then why do we still have apes around today. A common rebuttal it's not that we "evolved" from apes but that we share a common ancestor with apes and one lineage that came out of that ancestor became humans and the other became apes. But there's more to it than that; if you remember what I said about monophyly, it's not just that we evolved from apes, but we still are apes. A more accurate rebuttal would be that humans and chimpanzees (another species of ape) shared a common ancestor. So in short, asking why if humans evolved from apes, why are there still apes is like asking if doxins evolved from dogs, why are there still dogs.
6. The earth is fine tuned for life to live on it.
This statement is blatantly ridiculous because life can only inhabit the thin skin of the Earth. Most life is confined to within 10km of the surface (either way). The rest of the Earth is unihabitable. They may argue that the Earth resides in the habitable zone of the suns orbit but out of the billions of stars in our galaxy odds are some planets would end up in the habitable zone of the star.