I tuned into Christian radio for a few minutes this morning. The program was Hank Hanegraaff, "The Bible Answer Man," who is president of the Christian Research Institute (CRI). He invites listeners to call in. One caller was a minister who asked Hank for a five-minute monologue he could give to convince people that creationism is correct and evolution is wrong.
I'll give a quick summary, by memory, of Hank's answer.
(1) There are no transitions between kinds, only within kinds. [Hank definitely used the word "kind," and did not make use of terms like "species" or "genus" which may be more sharply defined biological terms.] Darwin can be forgiven in this regard, says Hank, because in Darwin's time fossils were still a rarity. Now that we have a great deal of fossils in collections throughout the world, we can see (says H) that there simply are no transitional organisms.
(2) In Darwin's time people thought the fertilized human egg was a simple ball of protoplasm. We now know it is incredibly complex. Nothing that complicated could have arisen by chance.
(3) The Earth is precisely located in its orbit around the Sun; not too hot, not too cold. The Moon is just the right mass to form some tides on Earth, but not to make really huge tides. Only a caring God could have arranged this.
(4) The mind is not equal to the brain. Science cannot explain this. Also, we cannot explain ethics without a God.
Hank speaks with great sincerity in his voice. I get the feeling he truly believes creationism is how it happened. He probably believes that only people who have been blinded by the wiles of the Devil could ever swallow the pack of lies that he believes evolution theory to be.
I pass these ideas of Hanegraaff on since they might be used by your debate opponent, and you should be prepared to rebut them.
Here are my own thoughts, with the understanding that I have never done much reading on biology and am far from any kind of authority on that subject...
(1) Aren't horses and donkeys an example of one species (or "kind" if you prefer) caught in the process of diverging into two species? You can mate them, and sometimes they will give birth to a live offspring called a mule, but the mule is always (?) sterile, so you could say that the mating process is only partially successful. Also, I saw recently in a magazine (I think it was Scientific American) where a fossilized imprint of a dinosaur with feathers has been found in some place like Mongolia. Would this satisfy Hank as being an example of a transition between the dinosaur 'kind' and the bird 'kind'?
(2) "Chance" is kind of a misleading term to use for evolutionary change, isn't it? Evolution is not teleological, but there is a natural selection aspect to it which weeds out things not good at reproducing.
(3) Given how many stars there are in the universe, if even ten percent of them have planets, that is a staggering number of planets. So it seems reasonable that here and there, peppered throughout the universe, there are planets which are amenable to life getting started. Once life does start, evolution gives it the ability to adapt to slow changes in things like temperature, humidity, windiness, and so on. Ice Age coming? No problem. Migrate to a tropical latitude, or migrate to lower altitude, or evolve somewhat thicker fur. Why a creationist should be so concerned with tides, I don't know, and Hank did not say why. Isn't it evolutionists who suggest tidal pools as a good environment for getting life started?
(4) AFAIK, science has not yet been able to say much about this issue. I don't doubt that in a thousand years we will know much more about how consciousness and even a sense of ethics can arise from a few pounds of brain tissue.
I have just thrown some of my thoughts out here as to how to answer these four objections that creationists have. You may well be able to do better.