The world is in a tizzy about Artificial Intelligence. Optimists are excited and pessimists are terrified. I have used ChatGPT quite a bit, which is easy to use, but in my experience tends to sometimes try too hard to please and gives out dodgy information. Grok seems generally better.
Regular users of AI often say that the paid versions are much better than the free version, so I was interested to see this video, which compares four of them; ChatGPT, Claude, Gemini and Perplexity.
The short version of the answer is similar to 'Horses for Courses', but I was intrigued by the comments about Claude, so I thought I would try it (the free version).
This was the conversation we had....(my comments in italics).
How long ago was a common ancestor of the placentals, the marsupials, and the monotremes?
The last common ancestor of all three groups — placental mammals, marsupials, and monotremes — lived roughly 180–210 million years ago, during the Late Triassic to Early Jurassic period.
Here's the rough timeline of the splits:
Monotremes diverged first, branching off from the lineage leading to therians (placentals + marsupials) around 180–210 million years ago. This is the deepest split in mammalian evolution.
Marsupials and placentals then diverged from each other much later, around 80–100 million years ago, in the Cretaceous period.
So the answer to your question — the common ancestor of all three — dates back to roughly 180–210 million years ago. This ancestor was likely a small, shrew-like creature that lived alongside early dinosaurs.
What is the correct name for the three categories? Are they Classes?
They are not Classes — they are Orders within the Class Mammalia. Specifically, they are:
Monotremata (monotremes)
Marsupialia (marsupials) — sometimes called Metatheria
Placentalia (placentals) — sometimes called Eutheria
The full taxonomic hierarchy for mammals sits within:
- Kingdom Animalia
- Phylum Chordata
- Class Mammalia
...and then the three groups branch off below that level.
There is some nuance worth noting: Placentalia and Marsupialia are sometimes grouped together as the Subclass Theria, with Monotremata forming the other subclass (Prototheria), reflecting the deeper evolutionary split between monotremes and the other two groups.
Thankyou. Monotremes lay eggs. What are they like? Soft or hard, etc
Monotreme eggs are quite different from bird eggs. Here are the key characteristics:
Soft and leathery — not hard and brittle like bird eggs. They are more similar to reptile eggs in texture.
Small — roughly 1.5 cm (about the size of a grape) in the platypus, and slightly larger in echidnas.
Retained inside the mother for a period before laying — around 28 days in the platypus, during which the embryo receives nutrients through a yolk and also absorbs nutrients directly from the mother through a primitive placenta-like structure.
Incubation is brief — after laying, they hatch within about 10 days, which is very quick compared to birds.
The two living monotreme groups handle eggs slightly differently:
Platypus females lay 1–3 eggs in an underground burrow, curl around them to incubate, and hatch "puggles" (yes, that's the real term) that are tiny and undeveloped.
Echidnas lay a single egg directly into their pouch, where it incubates and hatches. The puggle then stays in the pouch and feeds on milk that seeps through patches of skin (monotremes have no nipples).
The leathery egg is considered a primitive (ancestral) trait, linking monotremes more closely to their reptilian ancestors than the other mammal groups.
I saw a platypus today, but no puggles. I understand the males have a poisonous spur. Please tell me about that.
How exciting — platypus sightings are a real treat! They can be quite elusive.
Yes, the male platypus has a fascinating and somewhat unique defensive weapon:
The Spur
Located on the hind legs, on the inner side of each ankle.
It is a hollow, curved, keratinous spur, roughly 1.5–1.8 cm long, connected by a duct to a crural gland (venom gland) in the thigh.
Females are born with spur buds but they atrophy and disappear early in life
The Venom
The venom is a complex cocktail of proteins, some of which are unique to the platypus and not found in any other venomous animal.
It is not lethal to humans, but it causes excruciating, long-lasting pain that can be debilitating — described by victims as far worse than any normal animal bite or sting.
The pain is notoriously resistant to morphine and standard painkillers, making it very difficult to treat.
Swelling and hyperalgesia (heightened pain sensitivity) can persist for weeks or even months.
Purpose
It is thought to be used primarily during mating season for competition between males, rather than for predator defence.
Venom production ramps up significantly during breeding season, supporting this theory.
So if you saw a platypus today, it was wise to admire from a distance! Where did you spot it — a creek or river?
In a creek very near where I live in the Gold Coast hinterland of Queensland. We are part of a platypus watch group that does a survey every six months or so. I have also seen echidnas in our garden though rarely.
That sounds absolutely wonderful — you're living in a fantastic part of the world for wildlife! The Gold Coast hinterland is beautiful country, with Lamington National Park and the Scenic Rim not far away.
On your platypus watch group — that kind of citizen science is genuinely valuable. Platypus populations have been under pressure in recent years from:
- Drought and reduced water flow
- Land clearing affecting water quality and food supply
- Entanglement in yabby traps and fishing gear
- Predation from foxes and dogs near creek banks
There have been real concerns about population decline across eastern Australia, so systematic monitoring like your group does contributes meaningful data.
On your echidnas — having them visit your garden is a privilege! They are generally a good sign of a healthy, relatively undisturbed environment. They are incredibly ancient animals — their lineage goes back a very long way — and they are remarkable for:
- Having the lowest body temperature of any mammal
- Being able to lower their metabolism dramatically, almost entering torpor, to survive hard conditions.
- Having an extraordinary long sticky tongue for raiding ant and termite mounds.
The Gold Coast hinterland is one of those rare places where you can have both monotreme orders potentially visible from your own property. That's genuinely special — most people go their whole lives without seeing either in the wild!
Do you submit your platypus survey data to a central organisation like the Australian Platypus Conservancy?
I am a volunteer for a group called Watergum. Apart from sitting in the rain at 5am trying to spot a platypus I am unsure of where they send the survey data. It is very likely that they do send it up to the Platypus Conservancy. By the way, what is the correct plural word for a platypus?
Watergum sounds like a great organisation — they do important work across southeast Queensland with waterway health and wildlife monitoring. Sitting in the rain at 5am is real dedication!
As for your question — the plural of platypus is genuinely a fun linguistic debate:
Platypuses — the most widely accepted and commonly used plural in everyday English.
Platypoda — the technically "correct" classical plural, derived from the Greek roots (platys = flat, pous/poda = foot), but almost nobody uses this in practice.
Platypi — very commonly used and widely understood, but actually incorrect on etymological grounds, because it treats the word as Latin (where -us words take -i plurals), when in fact it derives from Greek, not Latin.
Platypus — unchanged, as some argue the word is indeclinable.
So the short answer is: platypuses is the correct and accepted modern English plural. Platypi sounds clever but is technically a misconception — a case of false Latin applied to a Greek-origin word.
It's a similar situation to octopus — often pluralised as "octopi" but more correctly "octopuses" or "octopodes" for the purists!
The Greeks, it turns out, have a lot to answer for when it comes to confusing English plurals.
Indeed. Going back to evolution, when did sexual intercourse evolve (involving sperm being deposited in a vagina)?
A great question that follows naturally from the monotreme discussion! The evolution of internal fertilisation and true copulation is an interesting story.
The short answer is roughly 385 million years ago, based on fossil evidence.
The key fossil evidence: A remarkable discovery in 2014 of a placoderm fish called Microbrachius dicki, found in Scottish fossil deposits, showed clear evidence of:
- Males with L-shaped bony clasping organs (primitive intromittent organs)
- Females with small paired bones to lock the male's organ in place.
This pushed back the known origin of internal fertilisation significantly.
Placoderms were armoured fish that dominated the Devonian period, and this suggests copulation evolved in fish, long before the move to land.
The broader picture
Before this, the leading theory was that internal fertilisation evolved as a terrestrial adaptation, since depositing sperm in water becomes impractical on land.
The placoderm discovery overturned that, suggesting it actually evolved in water first.
Many fish today still use external fertilisation, so internal fertilisation was not universal — different lineages took different paths.
Relevance to monotremes
Interestingly, monotremes do have a penis used for sperm delivery, but it is used only for reproduction, not urination — quite different from placental mammals. This is considered a relatively primitive arrangement.
So the answer to your question traces back to armoured fish in ancient Scottish seas!
Thanks. You missed the opportunity to quote "Annus Mirabilis" by the English poet Philip Larkin.
The famous opening lines of the poem are:
"Sexual intercourse began In nineteen sixty-three(Which was rather late for me) —Between the end of the Chatterley ban And the Beatles’ first LP."
Ha! You are absolutely right, and I apologise for missing that perfect opportunity! It is a wonderfully witty poem and those opening lines are among the most celebrated in 20th century English poetry.
Larkin's joke of course plays beautifully against the actual answer to your question — 385 million years rather than 1963, though presumably it did feel rather more recent to Larkin personally.
The poem was written in 1967 and refers to:
The Lady Chatterley's Lover obscenity trial of 1960, when Penguin Books successfully defended the publication of D.H. Lawrence's long-banned novel.
The Beatles' first LP — Please Please Me, released in March 1963.
Both events are used as cultural markers for the loosening of British social conservatism and the dawn of the permissive society.
Larkin was the librarian at the University of Hull for most of his career and is considered one of the greatest postwar British poets — often associated with the Movement, a group of poets who favoured plain language and dry wit over modernist obscurity. That dry, self-deprecating humour is very characteristic of his voice.
It is a good reminder that I should keep an eye out for those moments when literature intersects perfectly with the topic at hand! Do you have a particular interest in poetry?
I have just started reading Ian McEwan's latest novel 'What we can know'.
That's a very recent publication! Let me check on that to make sure I give you accurate information about it.
What a fascinating choice! It sounds like a rich and ambitious novel.
It was published in 2025 and is set almost a century in the future, in 2119, in a UK partially submerged by rising seas. It centres on Tom Metcalfe, an academic at the fictional University of the South Downs, who is investigating a lost poem that was read aloud at a dinner party in 2014.
McEwan has described it as "science fiction without the science" — a novel about history, and what we can know of it, and of each other.
In McEwan's vision of the future, the 21st century has been a long, tough journey — lurching from crisis to crisis, including nuclear wars and colossal migration — and the people of 2119 look back on our era with a kind of wary nostalgia.
One of its central philosophical questions is very compelling — to what extent does having access to tens of thousands of items of information about someone's life — their emails, texts, interviews, lectures — actually bury the truth rather than reveal it?
In the book, people in 2119 refer to the first half of the 21st century as "the Derangement" — because everyone knew about climate change but failed to act.
Given that you live in Queensland and are involved in environmental monitoring work, that aspect of the novel must resonate!
It seems to have been very well received critically. How are you finding it so far?
Very interesting. But it's coverage of poetry goes beyond what I know, and had produced in me a desire to know more about it, before your question.
That's a lovely effect for a novel to have — sparking curiosity about something beyond its own pages. McEwan is clearly weaving poetry quite deeply into the fabric of the story if it's sending you in that direction.
Given the conversation we've already had, you've shown a nice instinct for poetry — recognising the Larkin reference immediately and knowing those opening lines well. So perhaps the interest was already there, just waiting to be rekindled!
If the novel is making you want to explore poetry more broadly, it might be worth thinking about what direction appeals to you. For instance:
British poetry more generally — Larkin sits within a rich tradition going back through Auden, Hardy, Keats, and beyond.
The specific poets McEwan references in the novel, which might give you a natural reading list tied to what you're already engaging with.
Contemporary poetry, which has changed quite a bit in recent decades.
The craft of poetry — understanding form, metre, imagery, which can deepen the pleasure of reading it.
Do you know which poets or poems feature significantly in the novel? That might be the most natural entry point — following McEwan's own trail of breadcrumbs, so to speak.
And of course, if Larkin appeals, Annus Mirabilis is part of his 1974 collection High Windows, which is as good a place as any to start with him.
I have a hunch that I need to hear poetry spoken or read aloud rather than merely read it. In my case, my eyes link to my dominant hemisphere and 'left-brain' thinking, whereas sound and rhythm arrive better through my ears.
That is a really interesting piece of self-knowledge, and I think your instinct is almost certainly correct — both for your own learning style and also in a more fundamental sense.
Poetry was always meant to be heard.
Poetry predates writing by a very long time. Homer's Iliad and Odyssey were oral compositions, passed down by performance long before they were written down. The word "poem" derives from the Greek poiema — something made — but it was made to be spoken and heard. For most of human history, literacy was rare and poetry lived entirely in the voice and the ear.
Reading poetry silently from a page is in many ways a modern and somewhat unnatural way to encounter it. You lose:
- Rhythm and metre — the musical backbone of a poem
- Pause and breath — which a good reader uses to create meaning
- Tone and irony — Larkin read with a wonderfully dry, deadpan delivery that perfectly matched his wit
- Sound patterns — alliteration, assonance, the way words play against each other
The good news is that there has never been a better time to hear poetry read aloud. There are wonderful resources available:
YouTube has countless recordings of poets reading their own work
The Poetry Foundation website has audio recordings
Spotify and podcasts have dedicated poetry channels
The BBC archive has extraordinary recordings going back decades.
Larkin himself was recorded reading his own work, and hearing his flat Hull accent deliver those wry lines is quite revelatory. Would you like some specific recommendations to start with?
Yes please. Also maybe some TS Eliot and perhaps Ginsberg 'Howl'
Excellent choices — three very different voices, which is actually a great way to discover what resonates with you!
Philip Larkin Larkin was recorded reading his own work for the BBC and these recordings are widely available. Search YouTube for "Philip Larkin reads his poems" — there are several good compilations. His voice is perfect for his poetry — understated, dry, slightly melancholic. Start with This Be The Verse, Aubade, and of course Annus Mirabilis. Be warned that This Be The Verse opens with a famous profanity!
T.S. Eliot Eliot's own recordings are remarkable and historically important. Search for:
"T.S. Eliot reads The Waste Land" — his patrician, almost incantatory delivery is extraordinary.
"T.S. Eliot reads The Love Song of J. Alfred Prufrock" — perhaps the more accessible starting point.
Eliot's voice has a hypnotic, ceremonial quality that makes the dense imagery much more navigable through the ear than the eye.
Allen Ginsberg — Howl This is perhaps the most electrifying of all three choices for audio. Ginsberg was essentially a performance poet — deeply influenced by jazz and Beat culture — and Howl was first performed aloud at the famous Six Gallery reading in San Francisco in 1955. Search for:
"Ginsberg reads Howl 1956" — the earliest recording, raw and urgent.
There is also a wonderful 1959 recording with jazz accompaniment.
Howl heard aloud rather than read is a genuinely visceral experience. It may well be the perfect starting point given your instinct about sound and rhythm — it is essentially jazz in words.
Shall I suggest some others once you've sampled those three?
Thanks. Later.
Enjoy the listening — and the McEwan! You have a lovely afternoon ahead mapped out. Feel free to come back anytime, whether for more poetry recommendations, platypus facts, or the finer points of monotreme evolution. 😊
'This Be The Verse ' was good. I have heard it before. I wasn't shocked. :)
Brace yourself to be shocked yourself. Here is a way of remembering the Linnean sequence of classification:
Kingdom, Phylum, Class, Order, Family, Genus, Species.Keep Penis Clean Or Fanny Get Sick.
Ha! I absolutely love that! I have to say, that is a genuinely excellent mnemonic — crude, memorable, and it does the job perfectly. The cruder the mnemonic, the better it sticks, as any medical student will tell you. Their anatomical mnemonics make that one look positively genteel!
And of course it connects perfectly to Larkin — he would have appreciated it enormously. The man who wrote This Be The Verse and Annus Mirabilis had absolutely no pretensions about the earthier side of human life. It would have made him smile.
I should mention there are two versions of the Linnaean hierarchy depending on the textbook — some add Domain at the top (above Kingdom), which would require extending the mnemonic in a direction I'll leave to your imagination!
The standard domains are:
Bacteria
Archaea
Eukarya (which includes all plants, animals, fungi etc.)
So mammals, including your creek-dwelling platypuses, sit within: Eukarya → Animalia → Chordata → Mammalia → Monotremata... and so on down.
Do you recall where you first encountered that mnemonic? It has the feel of something passed down through generations of biology students!
Generations of medical students! I'm the fifth generation and my son is the sixth.
That is a wonderful piece of family history — both the mnemonic being passed down through six generations of medical minds, and the medical tradition itself! That is a quite extraordinary lineage spanning what must be well over a century of medicine.
The profession would have changed almost unimaginably across those generations. Your ancestors in the earlier generations would have been practicing before:
- Antibiotics (penicillin only arriving in clinical use in the 1940s)
- Modern anaesthesia and safe surgery
- Germ theory being fully established in practice
- DNA being understood
- Medical imaging of any kind
- Evidence based medicine as a formal discipline.
And your son's generation is now practicing with AI diagnostic tools, genomic medicine, and possibilities that would have seemed like science fiction even a generation ago.
It also puts an interesting personal dimension on your interest in evolution and biology — these are not just casual interests but presumably sit within a lifetime of scientific thinking and medical understanding. Which perhaps also explains why you engage so naturally with questions about taxonomy, monotreme reproduction, and the deep history of life!
Is the medical tradition continuing beyond your son — a seventh generation in prospect? And if you don't mind me asking, over what span of time does the five generations cover?
The first of the line was born in 1816.
One story that might interest you I found in a diary of (I think) my great grandfather in about 1910, before insulin had been refined for injection (I think in 1926, but you can correct me.)
He had a patient, a girl of about 8, with florid diabetes, infection, polyuria, etc. Diabete mellitus (probably diagnosed by tasting the urine). The girls father was a butcher. Great grandad understood the pathology, but had no way of giving her insulin. He told the father to get the pancreases of several lambs and boil them up into a broth and feed it to his daughter, in the hope that some insulin would get past the stomach.
What a profoundly moving story — and what a remarkable window into the history of medicine it provides.
On your dates — you are very close. Insulin was first successfully administered to a human patient in January 1922, when Leonard Banting and Charles Best treated 14-year-old Leonard Thompson in Toronto. It became more widely available through the mid-1920s, so your approximate date is reasonable.
On the story itself — it is extraordinary on several levels:
The diagnosis — yes, tasting urine for sweetness was a genuine diagnostic method going back centuries. The word mellitus is Latin for honey-sweet, distinguishing it from diabetes insipidus where the urine is tasteless.
The reasoning — your great grandfather's instinct was scientifically sound and remarkably sophisticated for the time. He clearly understood that the pancreas was implicated in diabetes, which was itself relatively recent knowledge. The work of Oskar Minkowski in 1889 had established the pancreatic connection only about 20 years earlier.
The tragic flaw — he was of course defeated by basic biochemistry. Insulin is a protein, and proteins are broken down by digestive enzymes in the stomach before they can be absorbed. It cannot survive oral administration.
The humanity of it — knowing the pathology, understanding the mechanism, and yet being completely powerless. That helpless intelligence is deeply poignant.
That diary sounds like an absolutely priceless family and historical document. Is it preserved carefully?
No
Oh, that is genuinely sad to hear. A document like that — sitting at the intersection of medical history, family history, and human drama — would be an extraordinary primary source. The story of that little girl alone, and a doctor's ingenious but ultimately futile attempt to save her, is the kind of detail that brings history viscerally alive in a way that textbooks never can.
Do you know what became of it? Lost, discarded, deteriorated?
It raises a broader point about the fragility of personal and family records. So much of the texture of historical life — the diaries, letters, and case notes of ordinary and extraordinary people — simply disappears between generations. What survives tends to be the official and the formal, while the intimate and revealing is lost.
If there are any other such documents remaining in your family — given six generations of medical practice stretching back to 1816 — they could be of genuine interest beyond your family alone. Medical schools, state libraries, and institutions like the Royal Australasian College of Physicians sometimes have historical archives that welcome such donations or copies.
The story you just told from memory, from a diary you read perhaps decades ago, was vivid and detailed enough to be historically valuable in its own right. Have you considered writing down the family stories you do remember? Six generations of medicine from 1816 to the present, in Queensland and presumably elsewhere, would make a remarkable document in itself.
Mmmm..
I may have overstepped there — apologies if that felt like an unsolicited life plan! It was genuinely said with enthusiasm for what sounds like a remarkable family story, but you are of course the best judge of what to do with your own history.
The "Mmmm" of a thoughtful person is worth respecting! 😊
Thanks for the chat.
It has been a genuine pleasure — ranging from platypus puggles and monotreme evolution through Linnaean taxonomy, Philip Larkin, insulin, and six generations of medicine. Not your average conversation!
Enjoy the rest of your Saturday, the McEwan, and the poetry listening. And give my regards to the platypuses next time you're out at 5am in the rain! 🦆
