I've seen a study of the existing skulls that have been discovered which evolutionists say show the development of humans from apes. The lecturer showed which skulls were of apes that walked on four legs and which skulls show that their owners walked on two legs. It was the positioning of the hole where the brain was connected to the spinal cord. The four-legged owners had the hole further back on the base of the skull to enable the owner to walk on four legs and still be able to face forward. The others had the hole right in the middle to show that the owner walked on two legs. So he concluded that the skulls that had holes in the centre of its base were definitely human, and the ones that had the hole near the back of the base were ape. There were normal size human skulls and smaller ones, while the ape ones were of a similar size. He had a modern chimpanzee skull to show that an ape skull had the hole at the back of the base and not the middle.
Once he sorted the skulls into human and ape categories, he found none that filled the gap between ape and human - being a skull that had no forehead and sloped face as is the characteristic of ape skulls. If he had found one like that which had the hole in the centre of the base of the skull then he could conclude that its owner could well have filled in the gap between human and ape and would have been a true ape-man. But none of the skulls had that characteristic.
He also concluded that the difference in size of the human skulls were different types of true humans which once existed but became extinct. This is quite believable, because humans come in all shapes and sizes, from the pygmies of Africa to the large Scandinavian and Canadian tree lifters.
He said something interesting as well - humans before the tower of Babel event were culturally advanced, but when language groups were split up, individual language and cultural groups lacked people with knowledge and expertise and so the abilities and cultures went back to the stone age, and they had to start all over in gaining the necessary skills they had before. This explains the simple tools found with human skeletons. They were not a sign of a lack of intelligence, but a lack of knowledge, which their language group had lost at the tower of Babel.
I found this very enlightening, something I didn't know previously. Answers a lot of questions for me.