Seems to me like there are 15 species of shrimp on one side and 15 species of shrimp on the other side. So what your saying is that after millions of years of evolution, shrimp are still shrimp. Very interesting.
He is not showing you one animal changing into another "kind" of animal.
He is showing you yet another piece of evidence that shows how evolution is factual. Allopatric speciation is speciation caused by the divide of geological boundaries. You can take one population of something, one family, slit it in half with a barrier (in this case the land bridge which separated the shrimp populations) and over a short amount of time the shrimp on either side of the barrier became different from one another. They're no longer the same "family" but two distinct "families". Increase populations and increase the distances between them, and, as Sapiens example showed, there were 15 "families". They're no longer the same shrimp.
Just like the Galapagos finches, whose separation was water and distance, they adapted to their respective environments over time, changing their phenotypes to be better serve their surroundings. It all works the same way. It's all observable science. Predictable and testable.
This is the simplest, most basic, introductory part of evolutionary science. It is not some fabricated conspiracy against theology. It is as factual as one plus one equaling two.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Would you not say that the shrimp on the right side of the island had a common ancestor with the shrimp on the left - even though they were no longer part of the same group? You'd have to, right?
Would you not say that chihuahuas share a common ancestor with the gray wolf, even though those two animals are very different? Obviously, right?
Would you not say that whales shares a common ancestor with dolphins? They're certainly not the same thing, but they're related, aren't they?
Would you not say that white skin on humans was a geographic adaptation to their environment and that white-skinned people share a common ancestor with dark-skinned people? Well obviously, right?
So why would you not say that humans, which you admit share an incredible amount of similarities with chimpanzees, don't share a common ancestor with those chimpanzees?
How did these similar traits get passed down?
You share traits of your mother and father because, well they're your mom and dad, right? That's how biology works. Your children will share traits of both you and your wife, and they'll also have some traits of your parents and of her parents. Do you explain that by saying, "Well, I don't know how it works. I've never observed it..." Or would you understand those things to be true because you have a general understanding of how babies are made? Now imagine if you devoted your entire life to genetically studying the similarities between you and your parents - or you and your grandparents, or you and your great grand parents. That's what geneticists do. They study genetic lineage as far back as you could imagine.
We all share traits with the other great apes because we all share a common ancestor - we are all part of the same family. We all share these things because of simple biology. And simple biology is evolution.