That is why I said that the most amazing part is the way all the pieces fit together.
If all you had was the line of fossils going from Tetraclaenodon to modern horses and from Tetraclaenodon to rhinos, well you might have a point. It still would be strange to have all those animals that simply lived and died to have so many different morphological traits changing together but you could assert it.
But then why would horses and rhinos genetically test as being so close together? In your view, what is it about these two that make them test as genetically closer to each other than any thing else?
You also have occasional atavisms that show up in modern horses. In modern horses, the tibia and fibia are fused. Occasionally though, a horse will be born with these two bones unfused just as they were in what the fossils tell us are its ancestors. Horses have one toe per foot and have two degenerate toes called splints on each foot. Occasionally, horses will be born with these two extra toes fully formed just a they were in what the fossil record tells us are its ancestors. Why would they have the genes for making these parts if they never had them?
I also like the example of whales. YOu have this series of fossils going all the way back to a land dwelling ancestor. A group of modern land dwelling animals with an even number of toes on each hooved foot can also trace their ancestry back to this same group of fossil animals. The creatures included are animals such as deer, antelope, pigs, camels, and hippos.
Amazingly, genetic testing shows whales as being most closely related to these very animals. Why.
The fossil whales went through stages with legs that gradually changed. The rear legs basically went away and the front legs turned into flippers. DUring development, whale embryoes still make little hind legs that are later reabsorbed. Some whales are born with fully formed rear legs. Why would they have genes for making rear legs if they did not have ancestors with rear legs? The front flippers still have the humerous, radius, ulna, carpals, metacarpals and phylanges just like your arms do. The pelvis remains up in there somewhere.
Genetic testing revelas another curious aspect of the whales. Olfactory genes fall into two general categories. Animals such fish have genes for making a sense of smell to detect odors in water. Land dwelling animals have genes for detecting odord in air. Whales have dozens of genes that match the olfactory genes of land dwelling animals. Furthermore, since these genes are useless in the water, they have accumulated enough mutations to be not functional. Why would whales have genes that are only found in land dwelling ancesotrs if they did not have land dwelling ancestors?
There are many, many more such lines of evidence. Individually, you might be able to dismiss them in turn. But taken together, they present a compelling picture whose only conclusion is common descent. There is no other explanation for the wide range observations.
