Derek – Friday 16th July 2021

There remain tadpoles in the pond even in mid July. Some have left, others are almost frogs with froggy heads and limbs and the tail yet to be absorbed. Others are tadpole-like but with the addition of hind legs. Having got this far, will these tadpoles continue on to full frogdom? I am not sure and will keep watching.

And then there are tadpoles, quite a bit fatter than they were back in March, but with no legs or frog features. It’s unlikely these will develop further. Development genes haven’t kicked in, so they remain infants, Peter Pan-like for however long they live. Likely the cold of winter will kill them if they survive predation. These perpetual tadpoles can never reproduce, as only fully mature frogs have sex organs, but I doubt they are concerned, these oblivious eunuchs.

Being held back development-wise is called neoteny, also known as juvenilization. A well-known example is the axolotl from Mexico which doesn’t get to be a salamander, but is more fish-like, though it isn’t a fish but an amphibian in spite of having gills. It is locally known as the walking fish. Unlike the tadpole, they can reproduce. By adding thyroid hormone, axolotls can be induced to become salamanders which, having lungs, can go onto land.

Human beings are neotenic too. Our species has retained juvenile features into adulthood, looking more like, for example, infant chimpanzees than the adults with our globular skull with its thin bones, our broad, less hairy faces, large eyes and small teeth. Our arms are shorter than our legs, not much good for swinging from trees. Various sexual attributes are also indicative of neoteny. Of course, for us, unlike the remnant tadpoles, this is species-wide, though there are rare diseases which are caused by halted development.

There’s lots of wild carrot (Daucus carota) in the garden, much of it surrounding the wildflower bed but in other places too. This tall umbelliferous plant is easily confused with cow parsley, yarrow and hemlock which surfaces occasionally in the garden. The flower head, or umbel, of wild carrot has perhaps a hundred or so tiny white flowers. Close examination with a magnifying glass will show they have five petals. Once fertilized, the umbel becomes like a small tangled nest.

A number of times, I have been asked if wild carrot is edible. I look it up, and am told the roots are only edible when young, and even then they are quite stringy. I dig up a plant, not in this garden, but at home where we have a few plants in our back patch. And I find that wild carrot has wizened white roots. A very poor carrot. But then actual carrots weren’t originally up to much. It’s plant breeding that has made carrots both larger and tastier.

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