3/4 of the time period of life on earth was single-celled organisms.... but what people might miss when they look at this was that it was always an interactive system. What we call 'life' arose on top of chemical and physical processes that were only enabled by the flows of energy from (1) our young and energetic Sun and (2) our highly radioactive earth core. From the very point where the system started cooling down enough to allow carbon-carbon bonds to form the context of an aqueous environment, life was already there, the potentiality at least.
Of course, by this measure of our own history, we should expect ~3/4 of the Earth-like planets we discover to have nothing more advanced than single-celled life.
Now, the question of how single-celled life could have given rise to multicellular life and the origination of chromosomes, etc. is a whole other question, see slime molds.
Also mantis shrimp and naked mole rats. These are all creatures that have evolved a reproducing queen and sterile workers. However, I don't like the definition of calling a colony of such creatures an "organism" because it implies the only purpose of an organism to reproduce. You then end up getting weird edge cases like fig trees and fig wasps being a "single organism." Also, male/female pairs of humans would be a strong angle organism.
The organisms referred to by the GP are not insects. They are social colonies chiefly made up of insects as their component parts, but the whole is greater than the sum of parts. Consider fungi, microscopic plants, and even aphids which are farmed, to be parts of these organisms, not to mention the elaborate dwelling structures. These social organisms go far beyond individually embodied insects.
>With few exceptions, animals feed on organic matter, breathe oxygen, reproduce sexually, have specialized sense organs and a nervous system, and are able to respond rapidly to stimuli.
And are mobile. not rooted. At least thats what I learned as a kid as the main difference between animals and plants.
And the distinction gets even messier the further back in time you go.
Like, many life-forms among the Ediacaran biota are more closely related to modern animals than to plants, apparently. But for example charnia was a rooted life-form that was a filter feeder.
> And obviously that distinction should be messy when we go all the way back
No, the distinction has not been messier in the early times. On the contrary, the distinction was sharp in the beginning and it became messier later.
All the so-called eukaryotes, i.e. the living beings with nucleated cells, were animal-like in the beginning (perhaps close to two billion years ago), i.e. they were mobile and they fed by ingesting other living beings.
Much later, hundreds of millions of years later, various groups and subgroups of eukaryotes have become sedentary, in some cases because it was more efficient to wait the food to come to them, brought by water currents, than to pursue actively the food, in many other cases because they incorporated phototrophic living beings, e.g. blue-green algae, so they no longer needed organic food, and lastly, many groups have become sedentary after reverting to the mode of feeding of bacteria, i.e. instead of ingesting other living beings, which requires mobility, they went back to absorbing organic substances from the environment through their external surface, which does not require mobility for adults, but only for whatever kind of spores they use for reproduction. This last way of life is characteristic for fungi and for several other groups of living beings which resemble fungi without being related to them.
The first sedentary eukaryotes were the multicellular red algae and green algae (some green algae evolved much later to become the land plants), for which certain fossils are about one billion years old. Dubious fossils of red algae are a few hundred million years older.
During the early evolution of the multicellular animals, many groups have become sedentary as adults (e.g. the sponges), which in the beginning was somewhat unavoidable for any animals that became large, because a small larva could easily swim using cilia, a small adult could also use cilia, but for a big adult animal cilia are inefficient, so strong muscles are needed to move the body parts, to be able to use those parts for locomotion, and several tens of millions of years have passed until the animals evolved to have such muscles.
The start of the Cambrian is defined by the apparition of worms which were strong enough to burrow in the mud from the sea floor.
So the first animals ever recorded was 550million years ago, the amount of time humans been around is tens of thousands , or in the tech age, 2000 or so. It’s just cool thinking what even 50,000 years will be like, let alone a few million of years it takes for something to evolve
??? The timeline as some of us know it is: -4,400,000: Ardipithecus ramidus (half-arboreality); -2,300,000: Homo habilis (tools); -1,700,000: Homo erectus (organization and "world conquest"); -315,000: Homo Sapiens, approximate anatomy; -250,000: Homo Sapiens, current anatomy.
«Tens of thousands» may refer to the "Cro-Magnons"...
The constraints of DNA over RNA. That checksum double helix has slowed evolution up, which is what makes gene therapy interesting as a military application to survive hostile environments. Some bacteria like bacillus can survive radiation levels 100,000 times more than humans.
Personally I think if you can get a good idea of what the land based environment was like back then, you'll have a better idea of what changes are needed to extend lifespans in order to watch evolution taking place before your eyes. Currently only viruses and some bacteria like Gram negative pseudomonas can evolve quickly to changes in their hosts environment.
What makes their discovery interesting is the use of berthierine, an iron rich, aluminium rich clay.
>The analysis found that fossils with exceptional BST-type preservation were particularly enriched in an antibacterial clay called berthierine.
Pseudomonas loves iron in all states, and its bacteria that destroy skeletons, once animals and insects have picked at the flesh, so there might be some mileage in using aluminium based deodorants for a starter, in order to reduce bacterial levels as a strategy to extend lifespans, besides dietary supplements and fine control over our environment, like air quality.
> there might be some mileage in using aluminium based deodorants for a starter, in order to reduce bacterial levels as a strategy to extend lifespans
Aluminum might reduce bacterial levels, but it isn't exactly great for human health either. Especially at high concentrations: https://pubmed.ncbi.nlm.nih.gov/9164811/
Feeding by drip aka intravenous feeding aka parenteral nutrition has never been a good idea in many ways, and besides aluminium, they also used to give manganese via drip as well! Manganese should only ever be taken orally, but we cant control what we inhale. Manganism and Parkinson's has so much in common, and it could explain baby's and toddler's uncoordinated movements.
I'm one paragraph in and the article has immediately contradicted itself saying animals first appear in the fossil record 574mya and their arrival appears as a sudden explosion 539 to 485mya, which 574mya is outside of. It then says people believe animals evolved before the Cambrian period but can't explain why they're missing from the fossil record. Except there are plenty of known fossils from the Ediacaran, the period directly preceding the Cambrian. That's a helluva lot of problems in one paragraph so I think I'm gonna stop reading there.
> Estimates for animal antiquity exhibit a significant disconnect between those from molecular clocks, which indicate crown animals evolved ∼800 million years ago (Ma), and those from the fossil record, which extends only ∼574 Ma. Taphonomy is often held culpable: early animals were too small/soft/fragile to fossilise, or the circumstances that preserve them were uncommon in the early Neoproterozoic. We assess this idea by comparing Neoproterozoic fossilisation processes with those of the Cambrian and its abundant animal fossils. Cambrian Burgess Shale-type (BST) preservation captures animals in mudstones showing a narrow range of mineralogies; yet, fossiliferous Neoproterozoic mudstones rarely share the same mineralogy. Animal fossils are absent where BST preservation occurs in deposits ≥789 Ma, suggesting a soft maximum constraint on animal antiquity
> contradicted
There is no contradiction in saying that the earliest found occurrence of x is at some point in time and the first high concentration of x is at some other later point in time. It is actually expected.
E.g.: First tablets found in Sumer: -3500 ; bulk of earlier found tablets in Sumer: -3300.
The prose is unclear, but I expect by arrival they mean success/dominance, in the sense given by the phrase "truly arrived." See the definitions given at https://idioms.thefreedictionary.com/have+arrived. Seems like poor phrasing rather than straight up contradiction.
Moreover, while most animals preserved in fossils after the start of Cambrian (540 million years ago) can be clearly identified as relatives of known animals, most of the fossils dated before the start of Cambrian and presumed to be of animals cannot be determined with any certainty as relatives of known animals. There are various hypotheses about the nature of the Ediacaran animals, but none of them is reasonably certain.
The exception is that some Precambrian fossils come without doubt from some kind of sponges.
Unlike multicellular animals, which have appeared much later, multicellular red algae and green algae were already widespread one billion years ago.
Of course, by this measure of our own history, we should expect ~3/4 of the Earth-like planets we discover to have nothing more advanced than single-celled life.
Now, the question of how single-celled life could have given rise to multicellular life and the origination of chromosomes, etc. is a whole other question, see slime molds.