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The Lagoon

Page 56

by Armand Marie Leroi


  * Devin Henry suggests to me that Aristotle may have in mind here the features of children with Down Syndrome – trisomy 21 – who, though clearly human, don’t particularly resemble any ancestor.

  * In modern genetics ‘skipping generations’ due to segregating recessive alleles is distinguished from rare ‘atavisms’ due to mutation. But the distinction is not to be imposed on Aristotle – nor on Darwin for that matter.

  * Archestratus, who’s interested only in the edibility of marine creatures, says that Aenus on the Gulf of Saros produces large mussels, that Abydus, Parium and Ephesus, all on the Troad, respectively produce oysters and small cockles and smooth clams and that Mytilene produces scallops.

  * The scarab beetle, however, is said to lay eggs or larvae in dung.

  * Many scientists have measured the heads of many eels, but eel craniometry is an inconclusive science. Some investigators have agreed with Aristotle that head shape is the mark of different species, or at least races, of eels; others have sided with his opponents and attributed the difference to sex; yet others suggest that the difference lies in a purely plastic response to diet.

  * Platt identifies the gēs entera as earthworms; Peck as parasitic nematomorph worms of the genus Gordius; neither explains why. D’Arcy Thompson’s suggestion that the gēs entera are related to casentula, the name that Sicilian fishermen give to the leptocephalus larvae, seems unlikely since the leptocephalus is rare in inshore waters and does not live in mud.

  * The Atlantic blue-fin tuna, Thunnus thynnus, is now extinct in the Black Sea but migrated and spawned there in historical times, as Aristotle says it does. (But contra Aristotle it spawns elsewhere in the Mediterranean too.) A more serious error in his account is that he says that tuna lay ‘sack-like’ egg cases, but the tuna spawns many small, free-floating eggs. He may be thinking of the pelagic spawn of the frogfish, Lophius. He’s confused about its spawning behaviour too.

  * But Alcedo atthis does not, as Aristotle says, breed in winter, in Greece, in a large nest by the sea; it breeds in spring, in Central Europe, in a burrow in a riverbank. Aristotle does say that there are two kinds of alkyōn; one of them may, then, be a tern, but its breeding habits don’t match the alkyōn’s either. D’Arcy Thompson argues that Aristotle’s account of the alkyōn is heavily influenced by astrological myth, but Peck disagrees. It’s true, however, that one of the Pleiades was known as alkyōn.

  * It’s hard to judge the accuracy of these spawning times. In part that’s because, for all the effort that icthyologists – Rondelet, Cuvier and D’Arcy Thompson among them – have expended on identifying Aristotle’s fishes, we still don’t know what quite a few of them are. Take the korakinos: all we know about it, from Aristotle and other sources, is that it lives over rocks and spawns late in the year. It has been variously identified by Cuvier, Gesner and D’Arcy Thompson with the damselfish (Chromis chromis), the shi drum (Umbrina cirrosa) and brown meagre (Sciaena umbra), all of which, however, spawn in early to mid-summer. Besides the list given here, taken from Historia animalium VI, 17, Aristotle also tells us about the spawning seasons of various fish elsewhere in HA and they don’t always agree. For example, he tells us that the sargos spawns in spring and autumn (HA 543a7), autumn (HA 543b8) and thirty days after Poseidon (HA 543b15, HA 570a33) – roughly January. In fact, Diplodus sargus spawns between January and March (FishBase). Looking at the most securely identified fishes, I estimate he gets it right about half the time. That said, the data in FishBase need not apply to Greek waters.

  * As given above, the life history of the arktos (Eurasian brown bear, Ursus arctos arctos) makes sense. If Elaphebolion is roughly March/April, and it hibernates in December, that would give a gestation period of about nine months, not too far off the 7.5 months recorded in the panTHERIA database. Unfortunately, Aristotle also says – and says in the same chapter (Historia animalium VI, 30) – that the sow is pregnant for only thirty days, that is, gives birth in May. Many editors have tried many expedients to sort this out.

  * He doesn’t mean that they are monoecious – he simply hasn’t identified the sexual parts of flowers. It is sometimes said that Aristotle thinks that plants, putatively maleless animals such as the khannos and bees are parthenogens, but since he typically says they have the ‘male and female principle’ combined they are more like selfing hermaphrodites. He’s just not clear enough on the mechanics of reproduction in these creatures to enable us to draw the modern distinction.

  * Fig wasps are one of Aristotle’s spontaneous generators; in fact they have wonderfully complex life cycles.

  * The identification lies in the name, which is derived from kentron – ‘sting’. P. caricae lays its egg in B. psenes larvae from outside the fig via a spectacularly long ovipositor. Against this identification, Theophrastus suggests that it preys on the adults as they enter the fig.

  * Some tendentious archaeology dates the origin of the asexual strain at around eleven thousand years ago.

  * In 1881 a consortium of California farmers, including Governor Leland Stanford, learnt about fig pollination the hard way. Dreaming of fig plantations spanning the San Joachin Valley, they imported 14,000 cuttings from Smyrna. The cuttings flourished and grew into trees which bore figs, all of which shrivelled, turned yellow and fell. The Californians accused the Smyrna merchant, an unfortunate Syrian, of sending them the wrong kind of fig, which he denied. US Department of Agriculture and California State Board of Agriculture scientists were commissioned to get to the bottom of the matter. Wild figs teeming with wasps were duly imported and California’s fig industry was born.

  * Aristotle believes that bees collect honey. So he does not know that nectar is processed into honey in the hive by evaporation and enzymatic reactions.

  * There are a dozen or more Thymus species in Greece, and many hybrids, so I don’t know exactly what plants they mean.

  * I asked a Corinthian beekeeper where honeydew comes from. Corinth is a region famous for its honey since antiquity, and my informant was a man who came from a family that had kept bees for several generations and he had read a good deal about them. Even so, he did not know that honeydew is excreted by hemipterans.

  * Actually, Aristotle distinguishes six ‘kinds’ – genē – of bees: (i) a small, round, multicoloured working bee; (ii) a big, sluggish drone bee; (iii) a red leader bee; (iv) a black, broad-bellied robber bee; (v) a long bee that makes bad combs and resembles a wasp; (vi) a black, multicoloured leader bee. He’s clearly dealing here with three sexes or castes (worker, drone, queen) and at least two of the several subspecies of Apis mellifera that are found in Greece. He seems to reduce the problem by assuming that (i)–(iii) are related, as are (iv)–(vi), since they come from the same hives. But he never makes it clear that workers, drones and queens are really the same kind – that is, have the same form or eidos as regular males and females do, and that the other kinds do not. This seems to raise questions as to what, exactly, the ontological status of a genos is for Aristotle.

  * Given total ignorance of who copulates with whom, and what the products of those copulations might be, there are many more possible combinations that he does not consider, but that does not matter since he’ll prove to his satisfaction that bees do not copulate at all.

  * In fact, queens are reproductive females, drones are males and workers are (normally) sterile females. Virgin queens produce drones parthenogenetically. Queens mated to drones produce workers or queens depending on how much royal jelly the larvae are fed and other factors. Readers may be puzzled by Aristotle’s claim that workers can produce drones in the absence of a queen. But in any hive a certain fraction of workers do have ovaries and can, if needed, start producing eggs that hatch into drones. Such are the complexities of a haplo-diploid sex-determination system coupled to environment-dependent caste formation.

  * He also thinks that some over-winter, naked, in holes. In 1862 Philip Henry Gosse (Romance of Natural History, 2nd series) was still wondering whether this is tr
ue.

  * Chicken hatchlings are used in regeneration research since they can regrow lenses and retinas after experimental ablation. Since swallow hatchlings are more altricial than chicken hatchlings, they may well be even better at this, but it will be a hard-hearted, not to say brave, researcher who tries to find out.

  * Aristotle says that a newly born bear is very small and poorly formed, indeed that its limbs are unarticulated, and he also says that the mother bear (as well as the vixen) aids the ‘concoction’ of her cubs by licking them. This, via Roman exaggeration (Pliny, Ovid, Virgil), gave rise to the expression used by irate parents and coaches to their charges: ‘You need to be licked into shape.’

  * Zoologists call this the altricial–precocial spectrum. Altricial (= ‘imperfect’) and precocial (= ‘perfect’) were coined in 1835 by the Swedish zoologist Carl Jakob Sundevall, who used them as features by which to divide the birds into two taxa, Aves Altrices and Aves Praecoces. Sundevall does not credit Aristotle for the idea, yet in 1863 would write Die Thierarten des Aristoteles. Did Sundevall get it from Aristotle? Or was he later attracted to Aristotle by finding the idea there? Sundevall does credit Lorenz Oken for the idea; but where he got it from I do not know. Aristotle’s assessment of birds and mammal neonates along the imperfect–perfect/altricial–precocial spectrum is correct.

  * Appendix V.

  * Applying simple linear regression to modern data gives a moderately strong relationship in placental mammals of the form log(lifespan) = 0.77 log(gestation period) + 1.53, r2 = 0.6. Given that the red deer, Cervus elaphus, has a gestation period of 235 days, that predicts a maximum life span of around twenty-five years; the actual recorded maximum life span is twenty-seven years. I examined six of the associations among life-history features that Aristotle reports; they were all correct (Appendix VI). Actually, that’s not surprising since all these features are strongly associated with adult body size and hence with each other. However, the important point is that he’s looked to see what the sign of the relationship is – he didn’t assume it from some theory.

  * The problem of distinguishing causal from non-causal associations still plagues comparative biology. Evolutionary biologists will recognize the soundness of Aristotle’s attempt to solve it. Aristotle fails to see, however, that within oviparous fishes there is a positive association between fecundity and body size, but his claim is strictly correct for he refers to animals that swim (i.e. all fishes) and his comparison is between the selacheans, which are large and have relatively few offspring, and oviparous fishes, which are mostly small and have many.

  * So what is its cause? It’s likely that Aristotle thinks that both features – longevity and gestation time – are causally associated with body size, so: large animals live longer than small ones since they’re less vulnerable to fluctuations in the environment; they also have larger offspring; larger offspring require longer gestation times – ergo there is a positive association between gestation time and longevity. He certainly claims these associations, but he doesn’t spell the entire argument out very clearly; indeed, he tends to dwell on exceptions to the pattern (e.g. that horses are shorter lived but have longer gestation times than humans).

  * An extinct bantam breed from Adria, in the Veneto. In his Ornithologica (1600) Aldrovandi discusses them at length but doesn’t know what they are.

  * Aristotle does not know that it is the male pipefish that broods its young in its pouch; neither did the Kalloni fishermen that I asked.

  * Cf. E. Pound, ‘The Study in Aesthetics’, 1916.

  * The Southern Bug River, Kerch Strait, Ukraine–Russian frontier, in June. Curiously Aristotle insists that the mayfly is a tetrapod. This is probably because it rests on only four legs, holding the anterior pair in front of it, as if in prayer.

  * This idea is identical to the modern notion of a ‘senescence cost of reproduction’. The evidence for it is the same that Aristotle gave: various experimental manipulations that reduce reproductive effort increase longevity. The standard explanation – a diversion of resources to somatic maintenance, and hence longevity, rather than reproduction – is also Aristotle’s rephrased in terms of energy rather than ‘hot, moist’ matter or fat. The truth of this explanation remains unclear. That we are still discussing ageing in Aristotle’s terms is, perhaps, a mark less of his sophistication than of our physiological naïvité.

  * Snakes can’t regenerate their tails. Aristotle is probably thinking of the legless European glass lizard, Pseudopus apodus, which can. Common on Lesbos, they are easily mistaken for snakes.

  * Here he anticipates that quintessentially twenty-first-century concern of biomedical science: the search for totipotent stem cells from which new organs can be built at will. He would delight to learn of Hydra, that tiny sea-anemone-like creature, rich in stem cells, able to regenerate all parts, and one of the few animals that does not apparently age at all. It is an animal that has its ‘vital principle in every part’ complete.

  * Aristotle’s theory of the ageing of land parallels his theory of organismal ageing: land is born moist and as it grows old it dries.

  * Old mammals are poor at thermoregulation, but that is surely less a cause than a consequence of deeper processes. But Aristotle’s belief that ageing is caused by the decay of regulatory networks, and death caused by stochastic environmentally induced crises, may yet prove prescient.

  * The claim that sponges can sense touch and contract has long attracted derision. Even D’Arcy Thompson dismissed it as a fable. But Suberites and Tethya, two genera found in the Aegean, do visibly contract upon being touched; Chondrosia and Spongia may do so as well. How they do this in the absence of a true neuromuscular system is obscure. It would be interesting to test Aristotle’s report on sponge resistance by an experiment.

  * It wasn’t – but it has been the source of endless controversies over the tempo and mode of evolutionary change, notably in the 1970s when Eldredge and Gould proposed their theory of punctuated equilibrium to explain patterns observed in the fossil record.

  * A. O. Lovejoy, the Harvard historian, traced the origin and fate of these ideas, along with the Platonic ‘principle of plenitude’, in his classic work of intellectual history The Great Chain of Being, 1936. He found them in Augustine’s and Thomas Aquinas’ theology, Leibniz’s cosmology and Spinoza’s ethics, and in the writings of inter alia Addison, Locke, Pope, Diderot, Buffon, Herder, Schiller and Kant.

  * The rediscovery of Mendelian genetics and the elucidation of the structure of DNA.

  * He doesn’t define kinds this way – he’s not applying a Biological Species Definition – it’s just an observation.

  * Zoologists tend to suppose that hybridization is rather rare. But 10 per cent of bird species can hybridize, and there are many cases of hybrids giving rise to apparently stable species. That’s even more true of plants. Among Aristotle’s hybrids, dog × wolf can hybridize and produce fertile offspring; there are no verified cases of dog × fox hybrids, though Aristotle claims that the Lacossian hound is one. There are reports of chicken (Gallus domesticus) × partridge (Alectoris sp.) hybridization in captivity, but the phenomenon is clearly so rare that we may doubt whether Aristotle’s information is accurate.

  * Perhaps one other: biogeography. Aristotle certainly doesn’t think that all animal kinds are cosmopolitan, but he clearly does not, and cannot, have Humboldt’s and Darwin’s sense of the sheer strangeness of biotas in different parts of the world. But that’s perhaps more problematic to a creationist rather than an eternalist. The former may well wonder why the Creator made all those different biotas; the eternalist will just accept their presence as given.

  * In his Geography Strabo, who has a strong sense of tectonic instability, suggests that Lesbos was once connected to Mt Ida on the Asia Minor shore. In the Pleistocene Lesbos was indeed connected to the mainland of Asia Minor.

  * In the Meteorology Aristotle also talks about oryktos things. Here there is potential for confusion because in
English translations (e.g. H. D. P. Lee’s Loeb) oryktos is sometimes given as the Latin fossile whence our ‘fossil’. Since Aristotle’s fossiles are clearly inorganic stuff such as lumps of sulphur, it’s easy to assume that he’s confused and supposes that they have an organic origin. But oryktos and fossile only mean ‘dug up’. It is only in relatively modern times that ‘fossil’ acquired its current meaning as the petrified remains of once-living creatures – the sense in which I use it here.

  * Herodotus’ winged serpents, it has been suggested, were amphibian fossils from Makhtesh Ramon in the Negev. Others moot that they originated in descriptions of Spinosaurus deposits in the Western Desert, the depictions of serpents with feathered wings that can be found on Egyptian sarcophagi (cf. the British Museum) or cobras whose hoods that Herodotus mistook for wings.

 

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