The Past Condition of Organic Nature Lecture II. (of VI.), "Lectures to Working Men", at the Museum of Practical Geology, 1863, on Darwin's Work: "Origin of Species"

"The Past Condition of Organic Nature" by Thomas Henry Huxley is a lecture from the 1800s that dives into the nature of organic life and the evolution of life forms, reflecting discussions during the time of Darwin's evolution theories. The book examines the geological record, describing how layers of sediment show a history of life, and how fossils within those layers provide evidence, even though the record is complex and has gaps. Huxley points out that even with long stretches of time, fossil evidence connects past and current life, showing only a small number of animal groups have died out; as you go further down into the Earth's layers, the forms of life become more different, showcasing how life on Earth has developed over time.