Ruth Padel is Darwin’s great-great-granddaughter. Her grandmother, Nora Barlow is remembered with great affection in her preface to the poems
I was wondering if Nora might have met Darwin, but alas no, for she was born in 1885, 3 years after her grandfather’s death
My own great-great-grandmother, born in 1867, died in 1970. I can remember only one visit to her house, a cold (but not damp) place full of looming large pieces of furniture & smelling of polish, but strangely have no memory of what she looked like
I once mentioned her to a friend, who sort of gulped then said: My grandfather was born in 1855!
We looked at each other & tried to get to grips with this extraordinary difference (her grandfather married late & was 55 when her father was born; I come from a long line of teenage mothers)
As far as I know historical demographers still believe that the average length of a human generation in recorded history has remained pretty constant at around 25-30 years.
This surprises those who think that people used to start their families at a very young age – maybe 12 or 13. But the date of birth of your first child is not the determining factor. In order for there to be generations, there must be grandchildren, so at least one of your children must survive long enough to have a child of their own. Childhood mortality, as much as maternal age, determines the average generation length
On average therefore there are only about 50 ancestors standing on the direct maternal or paternal lines which link us back to the fall of the Roman Empire, though the further back you go the more likely it is that the maternal & paternal lines will curl round each other in a complicated braid or plait
When I was introduced to ‘drunken walks’ as an undergraduate one of the standard questions we were set was about the expected time before the ‘extinction’ of a family. (We were still in Neanderthal times, so a family was deemed to die out with the generation which contained no son who would carry on the family name)
I cannot remember the details, & I certainly do not care to try & work them out again now, but the length of time was surprisingly short
In modern times in this country fertility has been analysed with respect to the female line, since we do not have detailed records of paternity. Last time I looked, the average generation length was about 27, though I expect it has lengthened a bit since then
In genetics generally, & population genetics in particular, there seems usually to be an assumption that generations & genes move together, more or less in a phalanx across time – essentially assuming that cross sectional is the same as longitudinal analysis
Although this is obviously mathematically convenient, the truth may have more in common with the way the sea breaks upon the shore, with some ripples moving up the beach more quickly than others
If it were possible, it would be interesting to explore what, if any, are the implications of allowing generation length to vary
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