Darwin Newsletter No. 20

All observation must be for or against some view…

Dear Friend of Darwin,

Today marks the 142nd anniversary of Charles Darwin’s death. As crappy anniversaries go, it’s certainly up there. But the more I read about Darwin, the more I’m astonished at how much he managed to cram into a life blighted by chronic illness. From small, seemingly inconsequential observations to major (r)evolutionary works, he was always working on something.

150 years ago this month, in April 1874, Darwin noticed many flowers had been destroyed in the wood of the Sandwalk—the path at the end of his garden where he did much of his thinking. He had observed this phenomenon over many years, but the damage seemed to have grown far worse that particular spring. Having examined the destroyed flowers—his beloved primroses, cowslips and polyanthuses—Darwin blamed the local birds. One of is sons suggested they might be after nectar. Darwin concurred.

Primroses growing in the Yorkshire Dales.

On making such an observation, you or I might think, oh, that’s interesting. We might even go so far as to spend a few seconds blurting out a post about it on social media to show how observant we are. But Darwin, being Darwin, decided to write a long letter to the prestigious science journal ‘Nature’, requesting feedback from its readers as to whether this flower-destruction by birds was a new habit local to his area, or a more widespread phenomenon. If the latter, Darwin reasoned, the birds’ behaviour must be instinctive. Darwin being Darwin, he soon received plenty of feedback. In particular, the chemist Edward Frankland, who had corresponded with Darwin previously, wrote to explain that he owned a captive bullfinch and canary, and happened to have a large bouquet of cowslips to hand, so had performed an experiment. The native bullfinch bit through the cowslips with precision, extracting the nectaries and young ovaries, while the non-native canary simply destroyed the flowers with wild abandon. Frankland concluded the native bullfinch’s expertise must be down to instinct. At Darwin’s behest, Frankland went on to perform further experiments. This and other correspondence led, of course, to Darwin writing a follow-up letter to ’Nature’, summarising the feedback and adding some further thoughts of his own.

When observing new phenomena, Darwin couldn’t help hypothesising. Indeed, he saw little point in observing unless it tested or inspired some hypothesis. As he had opined thirteen years earlier to another correspondent:

How odd it is that anyone should not see that all observation must be for or against some view if it is to be of any service!

At this time of year, the local greenfinches, bullfinches, and assorted fellow avian vandals seem to enjoy nothing more than biting off the newly opened flower-buds on the large cherry tree in our garden. I’ve noticed this activity over many springs, but had never stopped to think about it before. 142 years after his untimely demise, Darwin continues to show us how to look at the world in a better way.

Natural selection

A book you might enjoy:

The Golden Mole by Katherine Rundell
Interesting facts about remarkable species. An enjoyable light read.

More book reviews »

Missing links

Some Darwin-related articles you might find of interest:

1. Darwin’s plant specimens stored for 200 years to go on public display
   Specimens collected during the voyage of the Beagle have been unearthed at a Cambridge University archive.

2. Botanists analyze the role of pollinators in the evolution of flowers with various sexual forms
   A new study supports Darwin’s hypothesis that certain flowering plant species evolved heterostyly (male and female sex-organs of different relative lengths in different individual plants) to encourage cross-pollination by insects.
   Original paper: Convergent evolutionary patterns of heterostyly across angiosperms support the pollination-precision hypothesis.

3. After 10 years of work, landmark study reveals new ‘tree of life’ for all birds living today
   The extinction of the dinosaurs sparked an explosion of bird species, according to the largest-ever study of bird genetics.
   Original paper: Complexity of avian evolution revealed by family-level genomes.

4. Why do so many beetle species exist?
   Of the roughly one-million named insect species on Earth, about 400,000 are beetles. Diet seems to have played a key role in the evolution of the vast beetle family tree.

5. How seaweed became multicellular
   A deep dive into macroalgae genetics has uncovered the genetic underpinnings that enabled macroalgae, or ‘seaweed,’ to evolve multicellularity.
   Original paper: Macroalgal deep genomics illuminate multiple paths to aquatic, photosynthetic multicellularity.

6. It’s a myth that male animals are usually larger than females
   A new study has found that, in many mammal species, males are not larger than females.
   Original paper: New estimates indicate that males are not larger than females in most mammal species
   Comment: The original paper seems somewhat unfair in claiming that, in The Descent of Man, Darwin accepted as common knowledge the (incorrect) idea that male mammals are typically larger than females. Darwin did (correctly) point out that the sexes of many mammals differ in a number of ways, including in body-size; and he did (correctly) say that “with most animals when the male is larger than the female, he seems to have acquired his greater size by having conquered during many generations other males”; but I could not find any passage where Darwin claimed larger male mammals were the norm. Indeed, Darwin highlights numerous (admittedly non-mammalian) examples where females are typically larger than males.

7. Frans de Waal (1948–2024), primatologist who questioned the uniqueness of human minds
   Obituary of the researcher and prolific science communicator who laid bare the social lives of apes.
   See also: A remembrance of Frans de Waal.

8. Butterflies mimic each other’s flight behavior to avoid predators, show scientists
   Researchers have shown that inedible species of butterfly that mimic each other’s colour patterns have also evolved similar flight behaviours to warn predators and avoid being eaten.
   Original paper: Pervasive mimicry in flight behavior among aposematic butterflies.

9. William Buckland, megalosaurus and the Bible
   An account of a meeting of the Geological Society of London on 20th February 1824, in which two clergymen first presented Megalosaurus and Pleisiosaurus fossils.

Journal of researches

Among well(ish)-deserved short holidays, I’ve spent the last couple of weeks down my latest research rabbit-hole, finding out about the evolutionary history of pinnipeds (true seals, sea lions, fur seals, and walruses). As always, my latest research topic proved far more interesting—and diverting—than I’d realised. I only intended to uncover a few interesting evolutionary titbits about grey seals to mention in passing in my next chapter, but, as ever, I ended up opening a whole can of worms.

Darwin once wrote to his close friend, and inspiration, the geologist Sir Charles Lyell:

A naturalist’s life wd. be a happy one, if he had only to observe & never to write.

To which, I would add a corollary: a writer’s life would be a happy one, if they had only to research and never to write.

(I will finish this book one day, I promise!)

Expression of Emotions

Thanks as always for reading this newsletter. Please feel free to send feedback, and to recommend it to your most discerning friends—or even your worst enemies.

See you next time!

Richard Carter, FCD
friendsofdarwin.com
richardcarter.com

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