C'mon - I asked the question - is this AI slop or good stuff. There still seem to be some experts on here and I want their considered view.

Apologies for not including a preamble - the above is the text of a conversation with deepseek that I found convincing. And yes AI is better at being convincing than correct, but please reply with a counter refutation if possible.

Oops forgot to put in a preamble.

Your comment is interesting but "Ontogeny recapitulates phylogeny" is discredited. I am not an evolutionary scientist, but I can run and understand Deepseek, so apologies if I am being taken in by AI slop, but here is the text of my conversation with deepseek, which I find convincing.

Please refute this refutation if you can!!

Question: what is the evolutionary advantage of Ontogeny recapitulating phylogeny

To answer this accurately, we first need to clarify a crucial point: "Ontogeny recapitulates phylogeny" is not an evolutionary advantage. It is a biological hypothesis—and a largely discredited one at that.

The phrase was coined by Ernst Haeckel in the 1860s. It means "the development of an individual organism (ontogeny) replays the evolutionary history of its species (phylogeny)." Haeckel believed, for example, that a human embryo passes through stages resembling a fish, then an amphibian, then a reptile before becoming a mammal.

Modern biology has shown this is not literally true. Embryos do not replay adult ancestral forms. However, there is a related, valid concept called "recapitulation" or "phylotypic stage" that needs a different explanation.

Here is the breakdown of why the literal version is wrong, and what actual evolutionary advantages exist for the patterns we do see.

1. Why the literal version is wrong (and has no advantage)

If ontogeny literally recapitulated phylogeny, it would be a terrible evolutionary strategy. Here's why:

• It would be inefficient and dangerous: An embryo would have to grow a full set of fish gills, then dismantle them to build amphibian lungs, then dismantle those for reptile lungs. This wastes enormous energy and creates fragile intermediate stages.
• It would constrain evolution: If every stage of development had to correspond to an adult ancestor, evolution could never add a new feature without ruining the previous stage. You couldn't have a mammalian embryo with a placenta if it first had to be a free-swimming fish larva.
• It's factually incorrect: Human embryos never have functional gills or a functional fish tail. They have pharyngeal arches and a tail-like structure that are later repurposed into jaws, ears, and the coccyx. They are not replaying a fish.

2. The real pattern: Developmental constraints and "Phylotypic Stage"

What we actually observe is that early embryos of related species look similar, and they diverge later. This is called the phylotypic stage (or the "hourglass model").

The evolutionary advantage here is not "recapitulation" but conserved developmental mechanisms:

• Shared genetic toolkit: All animals (from flies to humans) use the same master genes (like Hox genes) to lay out the body plan. Mutating these early genes is almost always lethal. Therefore, evolution conserves these early stages. You can't change the foundation without destroying the house.
• Late-stage flexibility: Once the basic body plan is laid down, the later stages (growth of limbs, fins, wings, beaks) are more tolerant of mutation. This is where evolution tinkers freely. That's why a human, a bat, and a whale all have similar early embryos but wildly different adult arms.

The advantage: This "hourglass" pattern allows evolution to preserve a working body plan while still allowing massive diversification in the adult form. The early conservation is a constraint, not an advantage in itself. The advantage is that it prevents fatal errors.

3. Where "recapitulation" does have a real advantage (Co-option)

There is one sense in which Haeckel was onto something, and it does provide an advantage: co-option of ancestral genes.

Embryos don't replay ancestral adults, but they reuse ancestral genes for new purposes. For example:

• The gene that builds a fish's gill arch is the same gene that builds your jaw and middle ear bones.
• The gene that builds a reptile's scale is the same gene that builds your hair and feathers.

The advantage: Evolution is a tinkerer, not an engineer. It doesn't invent new genes from scratch; it recycles old ones. This is vastly more efficient. The "recapitulation" we see is actually molecular recycling—using the same genetic switches for different outcomes.

Summary

• Evolutionary advantage of literal "ontogeny recapitulates phylogeny"? None. It doesn't happen, and it would be a bad design.
• Evolutionary advantage of the real pattern (early similarity, late divergence)? It protects the fragile core body plan from lethal mutations while allowing rapid diversification of the adult form.
• Evolutionary advantage of gene reuse (co-option)? It allows fast, cheap innovation by repurposing existing genetic tools.

So the correct answer is: The premise is a myth. The real advantage is developmental robustness and genetic recycling, not literal recapitulation.

Question: so why do hen chicks have teeth

You're asking about a fascinating case that seems to contradict the idea that birds lost their teeth. The reality is that chicks don't normally have teeth in the sense of a functional, biting set, but they do have a structure often called an "egg tooth." This isn't a true tooth in the way a crocodile or human tooth is; it's a temporary, sharp protuberance used for a very specific purpose.

The "Egg Tooth": A Tool for Hatching

What you're likely referring to is the egg tooth (or caruncle). It is a small, hard, keratinized tip on the upper beak of a chick that helps it break out of the eggshell. It is not a mineralized tooth with enamel and dentin like our teeth or those of a crocodile. Instead, it's a transitory structure made of the same material as the beak, and it falls off or is absorbed shortly after hatching.

The Genetic "Blueprint" for Teeth Still Exists

The deeper evolutionary story here explains why this "tooth" appears and why real teeth sometimes show up in mutant chickens. Birds lost their actual teeth roughly 70 to 80 million years ago, and their ancestors developed beaks instead. However, they didn't lose the genes for making teeth. Those genetic instructions are still present, just turned off.

This is why scientists can trigger tooth formation in chickens. In a famous mutant strain called talpid2, a regulatory error causes chicken embryos to develop conical, reptilian-like teeth. These teeth resemble those of the alligator, a distant relative, showing that the ancient developmental program is still dormant in the chicken's DNA.

An Evolutionary Trade-Off

So, why don't normal chickens have these teeth? Because the genetic instructions for teeth were suppressed to allow for the development of the beak. The beak is a much more versatile tool for a bird's lifestyle—it's lighter for flight, can be shaped into countless forms for different diets, and allows birds to eat a variety of foods without needing to chew. The egg tooth is a perfect example of a temporary, specialized structure that serves a critical need (hatching) without interfering with the beak's primary functions later in life.

In short, hen chicks have an "egg tooth" for hatching, not a true tooth for eating. The capacity to grow real teeth is still hidden in their genes, but it's normally kept turned off to allow the beak—a far more useful evolutionary adaptation—to form.

Question: and why do embryos have tailbones

This is a great question because it gets right at the heart of the difference between "recapitulation" and how evolution actually works. The short answer is: embryos don't have tailbones—they have a tail. The tailbone (coccyx) is what's left after the tail is dismantled.

What actually happens in human embryos

Early in development, human embryos do grow a genuine tail—a real extension of the spine containing developing vertebrae. At around 4–5 weeks, it's actually longer than the rest of the body relative to the legs. It has somites (segments that form vertebrae), a neural tube, and a notochord running through it.

Then, at around 8 weeks, the tail stops growing and begins to regress. The vertebrae in it shrink and fuse into the small, fused bone at the base of your spine: the coccyx, or tailbone. You keep the coccyx for life—it's not a vestigial nothing, it anchors muscles and ligaments of the pelvic floor.

So the embryo doesn't "have a tailbone." It has a tail, and the tailbone is the remnant of that tail.

Why build a tail just to destroy it?

This is the key evolutionary point, and it connects directly to our earlier discussion of developmental constraints.

1. It's not "for" anything—it's a conserved developmental program.
The genes that build the posterior body axis (the Hox genes, Wnt signaling, etc.) are ancient and shared with all vertebrates. They build a tail in fish, reptiles, mammals, and us. The human embryo runs that program because it inherited it, not because the tail serves a purpose in a human.

2. The tail is later "trimmed" by a separate genetic signal.
What makes humans tailless isn't the absence of tail-building genes. It's the presence of a new signal that tells the tail cells to stop growing and undergo programmed cell death (apoptosis). So the sequence is: build tail then actively remove it.

3. Why not just skip the tail entirely?
Because evolution can't easily delete a deeply conserved early developmental stage. The tail-forming genes are wired into the basic body plan—they're also involved in forming the lower spine, the gut, and the cloaca. Knocking them out entirely would cause fatal defects. So evolution does the next best thing: let the tail form, then add a "stop and remove" signal on top.

The evolutionary advantage—such as it is

There isn't an advantage to having an embryonic tail in humans. The advantage is:

• A functional tail in our ancestors (for balance, locomotion, communication)—that's the original adaptation.
• Taillessness in the lineage leading to apes and humans—useful for upright posture and a different mode of locomotion.
• The coccyx—a useful anchor point for pelvic muscles, retained because it's cheap to keep and does a job.

The embryonic tail itself is a byproduct of our ancestry and our developmental wiring, not an adaptation. It's a "spandrel"—a structural consequence of how the body plan is built.

Connecting back to your first question

This is exactly why the literal "ontogeny recapitulates phylogeny" idea fails:

• The embryo doesn't replay an adult ancestor with a functional tail.
• It runs an ancestral developmental program (build a tail) and then runs a newer program (remove the tail) layered on top.
• What you see is conserved developmental machinery, not a replay of evolutionary history.

So: embryos have tails, not tailbones. The tailbone is what's left after the tail is removed. And the reason the tail forms at all is that the genetic program for building one is ancient, deeply embedded, and easier to suppress late than to delete early.

I haven't written a cheque in nearly 20 years! Every now and then I get a refund cheque from Amex and its a real pain trying to bank it - and yes that includes scanning or photographing.

So how do you steal expertise, old boy? Not by hacking their network, or microfilming their documents!

Crikey mate, the only way I can think of is to poach someone with expertise. And the knowhow in their brains isn't secret.

Oh wait a mo - thats what they did.

I always laugh when some article says "industrial secrets" have been stolen. There really is no such thing as an industrial secret.

Expertise - yes. You need a lot of that to build your own doo-daddle widget, but plans and designs - no Those documents leave out more info than they give you. Any software or hardware engineer worth their salt can do a better job by tearing down of an existing bit of kit to work out most of the information they need to design their own stuff.

If you don't believe me just read the tech manual for your latest electronic gadget - did that suddenly make you an expert in using the gadget? or more puzzled than when you started.

Still don't believe me? Go to github and read some source code. Oh wait, I'm wrong - there are lots of programmers out there that just love documenting their secret sauce!

Nope - Maths works with axiomatic models and one of the axioms for Euclidean geometry is that space is continuous. So circles can be perfect. In addition pi crops up in all kinds of places apart from geometry for example infinite series . . . .
Your issue is whether our Euclidean geometry model is an accurate representation of the world around us. You may or may not be correct in thinking that quantum mechanics implies that space comes in "discrete" lumps when you get down to the Planck distance, but pi and its properties don't rely on quantum models.

Guys, Just accept that you are falling behind in yet another technology race.

I, for one, welcome our new masters - Ni Hao!

I call bullshit. If some brilliant young scientist has a great insight but needs time to analyse the data and get their arguments in order, then how is it that the non-brilliant poacher can get the job done faster?

My guess is that someone is raising these bogus arguments in the hope of creating barriers to publication that can be used to delay the entire openness process.

Whenever these stories surface, no-one ever speculates about the type of secret that we are supposed to care about.
Passwords? that's already a busted flush - just look at the spread of OTP.
In my experience, most secrets are about avoiding embarrassment over top brass misdeeds, or financial info that will be profitable only if leaked immediately.
I struggle to think of anything that needs to stay secret for more than a few weeks before it is worthless.

What is this "real world" of which you speak?

All I can say is that I didnt hear overloud boomboxes on the streets, or in the parks. Of course there may be rough estates where the problem lies, but at least some of the dancing is non-intrusive.

Loud boom boxes are one thing, but I would guess that street musicians were playing for the dancers in former times.

I know, but the dancing was everywhere we went, so we got used to the sight and accepted it for normality in China