Reddit reviews Evolution: The Story of Life on Earth

Looks like Dr. Pritchard is still getting set up, and it's a quiet morning, so I'll throw in a few suggestions.

There are two different approaches. To deal with the creationist questions/objections, an excellent source of information is Talk Origins, which has an extensive collection of Creationist claims and debunking.

For more general information, the original Origin of Species is a good source, though it's rather out of date and doesn't address genetics.

What age group were you looking at for books? For the 8-13 year old range, Evolution: How We and All Living Things Came to Be is decent, though a bit simplistic. For somewhat older audiences (high school/undergraduate) Evolution: The Story of Life on Earth is very approachable and a fun read. I can suggest others, but that should get you started.

Evolution: The Story of Life on Earth https://www.amazon.com/dp/0809043114/ref=cm_sw_r_cp_apa_bC7VzbZPGV3GM

It's a comic book.

Comic book form.

Disclaimer: I am not a scientist, but I am not 100% speculating either. I cannot provide deep explanations, but I hope I can steer you in the right track.

Mutations occur randomly.

Some mutations are easy to come by and occur many times, but others are more complicated and may have occurred only once or only a handful of times.

For example, photosynthesis is present in certain bacteria and in plants, but apparently only evolved once: the plants simply incorporated the photosynthesis bacterias in their cells to have that advantage (I read that in the Evolution comic book, a great read).

Now, back to reproductive organs, initially, all life was sexless: reproduction was via mitosis and at some point, the genes for sexual reproduction occurred.

It may have occurred only once, or at least, was passed down to us only once.

It is quite possible that all of the genes which decide where the sexual organs are placed are actually from the same common ancestor, the common ancestor to all creatures which reproduce sexually.

You see, sexual reproduction improves the selective process (again, same book as reference), so that first common ancestor would have had quite an advantage compared to the non sexual living creatures.

From that point, evolution will still work. That's why genitals differ from animal to animal, but unless it provides an selective advantage to have genitals in a different place, such a mutation will die out.

Edit: this is the book with a NON-REFERAL link: http://www.amazon.com/Evolution-Story-Earth-Jay-Hosler/dp/0809043114