The children who revealed our origins

When William Erasmus Darwin was born in December 1839, his father Charles began to meticulously record observations of his firstborn in a notebook.

Now housed at Cambridge University Library, it reads more like a research document than like that of a new parent blissfully observing his son's behaviour, as the opening comments reveal:

"During first week, yawned, streatched [sic] himself just like old person - chiefly upper extremities - hiccupped - sneezes sucked…."

Today we know a good deal about Darwin's theories. We know far less about how his private life - particularly his family - contributed to his work. But his vast collection of letters and the notebook reveal an intriguing side to the founding father of evolution: Darwin as a family man.

What's more, his children's development helped inform his understanding of human evolution.

Darwin's son William was born a year after the scientist first met London Zoo's first orangutan, Jenny.

"The orangutan for Darwin was like a window into the origins of mankind," says John van Wyhe of the National University of Singapore and director of Darwin Online, which hosts a collection of all of Darwin's published works.

At this time, Darwin was already forming ideas about where humans came from, but he had never met one of our close ape relatives to test these theories. His encounter with Jenny helped cement his idea that that we share a common ancestor with apes.

He was already looking for a "real relationship between humans and apes", says van Wyhe. When he saw Jenny's facial expressions and noticed her social behaviour, it reaffirmed his ideas.

Read the full article here.