One hundred and seventy years after Charles Darwin journeyed to the Galapagos islands, his great-great-grandson retraces the voyage that did so much to shape Darwin's understanding of evolution. Chris Darwin 's contemporary account of the islands have evolved in recent years is interspersed with Charles Darwin 's own observations as recorded in his journals. And Chris reflects on how this famous ancestry has shaped his own life - despite failing A-level biology. Producer Ruth Evans