Yes, we're cousins to arthropods (insects, say) and mollusks, (those giant squids and the like).
How do we know?
Well the scientists had thought our relationships with them were almost as remote as with seaweed or oak-trees.
But they were wrong!
Results of research into the genetics of simple arthropods (fruit-flies) produced some facts, with implications that `scientists' still haven't fully grasped, and so don't much talk about.
Simply put: we, and squids, insects and all, share some basic DNA patterns. And we remain fairly close, even after all this time. And those DNA "patterns" - though altered by duplications in humans' case - still `work' (after a fashion) across all three phyla - arthropods, vertebrates and mollusks!
Even after the 500,000,000 years (or more) since we went our separate ways!
We could think that humans and arthropods, insects say, have been widely different for millions and millions of years?
After all, we vertebrates have four limbs, tied to a spine running down our back ("top-side" in most mammals), controlled / connected via a central nervous system (CNS) and brain.
And we have a mouth-stomach-anus chute that runs in front of the spine - "under-side" in most mammals.
Whereas the arthropods have no spine or skeleton, are multi-legged (the classic plan is: a pair of "legs" for each segment of what can be a many-segmented body). Their `central nervous system', maybe with one or more brain-like nodes, runs down the "under-side" of the body. And they have a mouth-stomach-anus channel lying along their "top-side" - where we'd have a spine.
Even so, those genetic researchers have (maybe reluctantly) proved that the same DNA patterns intitiate the same processes in all three phyla - vertebrates, mollusks and arthropods. Although the actual form those processes take may look different in some cases.
I.e - the DNA pattern that starts off the `make segments' in insects will start off some of a mammal's brain differentiations and the formation of cranial nodes along the `central nervous system' - which can tell us something interesting about our earliest ancestors.
That is, one branch interpreted `movement control needed' as reason to start segmenting edges & body, another branch decided to grow muscles around the (proto-mollusk) body, while our branch used that same DNA pattern to initiate brain and CNS changes - from a standing start!
[This might also tell us something about the probable timing for DNA - which was maybe an independent or `wild' replicator which became a parasite or symbiote - beginning to `help' with higher life in exchange for a free ride.]
A BLOB! A plate-like or pillow-like body, with no head, no limbs, no `central nervous system' and no stomach, living on the sea bed.
No stomach! How did it eat?
One side, probably the "under-side" of the body, had an absorbent skin or maybe a gelatinous covering which could directly "digest" material it was in contact with. Early on it likely adapted its `digesting' surface into a slit or groove extending full length of the body.
But our common ancestor did have eyes. An indeterminate number of rudimentary light-sensitive patches, probably on the top-side and probably most of them above one end of the `digestion groove' running underneath its body. And that edge therefore became the front or head - no other reason.
The blob could move so as to place its body on fresh food. Its movements, whether to get away from its own eating residues (i.e. move to more food), or in spasmodic response to something `seen' above, would be about the same as the locomotion of a slime mould: no central nervous system.
But its methods of moving and reacting were already beginning to make demands on the body structure; demands that would give to arthropods a segmented body, to mollusks a muscled edge (later tentacles in some), and a back-bone and side-fins to remaining proto-fish (later vertebrates' limbs).
Well, the research (plus info about `eyes' - below) led us to these conclusions (midnight 29th July '04). The mouth - stomach - anus plan is radically different in all three subsequent phyla. Ditto for segments-legs / brain-cranials / tentacles etc. So those different ways of doing things came later, after we split up.
All three phyla have eyes. But many-faceted flies' eyes are nothing like the complex lenses that squids and mammals both have. And our vertebrate lenses are made of entirely different materials than a squid's mollusk eyes.
So we might think, as the scientists did, that eyes arose independently in the three different animal types - like wings of all sorts can arise from widely different materials and at any time. That hypothesis, called `convergent evolution', was the scientists' choice - but it seems they were wrong!
It turns out that there is a DNA pattern that starts eyes growing in all three phyla!
They're of a type called `hox genes'. And their action means our common ancestor already `grew' eyes as routine.
QUOTE - "the fly version will induce eyes in vertebrates, and vice versa" UNQUOTE.
Although the author goes on to warn "The end results will vary substantially" - as you might imagine!
Wednesday 4 August 2010
A unique blob-like creature that lived in the ocean approximately 425 million years ago is revealed in a 3D computer model in research published today in the journal Biology Letters.
The scientists, from Imperial College London, have developed a detailed 3D model of the only known fossilised specimen in the world of a creature called Drakozoon. The specimen was found by one of the team approximately 6 years ago in the Herefordshire Lagerstätte, one of England's richest deposits of soft-bodied fossils.
www3.imperial.ac.uk/~/news_4-8-2010-10-32-13 - [press release]
Modern science claims that it's finding `genes for one disease or another' in humans, and `genes for DDT resistance' in house-flies and mosquitoes etc.
And that each `gene' is specific and usable: so they say there's no danger of unintended consequences.
Examine each claim - it's a paradox!
E.g - how can a `gene' for DDT resistance exist when DDT was just recently invented?
From all above we're beginning to realize - a little late - that DNA is not a blueprint but merely a small and ancient multi-purpose toolkit, used as & when a body *wants* to do something extra.
So there's no such thing as `one gene' for a discrete attribute or condition. E.g. - in reality one `pattern' can switch on segments/legs in insects but alter brain shapes in mammals.
The results prove that our deck of `gene-cards' is very, very old and overlaps all animal life;
- that our bodies, and those of our parasites, will `take cards from the deck', as and when;
- that an unknown number of `wild cards' exist, but have different values depending on who gets them;
- and that unknown numbers of other DNA patterns are going to be involved in _any_ single effect - no matter how we try to prevent that happening.
Most of the clues for these conclusions came from `Brotherhood by Inversion' essay (or `As the Worm Turns') in `Natural History Magazine', by Stephen Jay Gould
Evidence file for:
"Retribution" and "Blind Science" pages and "Altruist Survivor".
Refs in equal2.txt & dive-rge.txt and maybe others by now.