Complex sentence: Hitching was a catastrophist and non-Darwinian evolutionist who believed evolution had occured due to a number of catastrophes, he was very critical of gradualism, he discussed in the book alternative evolutionary theories which he claimed have been ignored by the Neo-Darwinists.
Split into simpler sentences: Hitching was a catastrophist and non-Darwinian evolutionist who believed evolution had occurred due to a number of catastrophes; he was very critical of gradualism. He discussed in the book alternative evolutionary theories which he claimed have been ignored by the Neo-Darwinists.