Threesology Research Journal
The Devil's Advocate and 3's Research
~ 25 ~
~ The Study of Threes ~

Flag Counter
Researchers as of 8/29/2019

website translator plugin

Devil's Advocate Series:
1 2 3 4 5 6 7 8 9
10 11 12 13 14A
15 16 17 18
19 20 21 22A
23 24 25 26 27
28 29 30 A
30 B
31 32 33a
34 35 36
37 38 39 40 41 A
41 B

The following is a timeline which indicates there are others who are thinking along a similar trail as myself, though we are approaching developmental evolution from our individualized perspectives:

The Baritaar timeline

Now, contrast it with the preliminary timeline of my own:

Preliminary Timeline

Both of them display an effort to portray numerically identified sequences, even if the author of the first one is not singularly focused on this primary effort. Nonetheless, the information displays an active cognitive portrayal to pursue this as part of the overall sequences of events, even though this is not the conventional pursuit of how Biology or Zoology is being taught as a standardized perspective in the classroom. While I have not made an attempt to contact the author, I will do so after the is page is finished since I have an array of images and thoughts in mind that I need to follow up on as they come to bear on my consciousness to the point of being able to transcribe them.

While it is clear that the author is not trying to cover as much ground as I am in a single image, it is also clear there is a distinct originality of effort being illustrated in the combinations of information being provided— no doubt in an intentional mode of simplicity so as to not complicate the visual aspect of information that may or may not be familiar to those who chance upon the information. Perhaps the author and I as well as any other interested reader will find it opportunistically valuable to join in a concerted collaborative effort to facilitate a larger combined expression of the many numerically identifiable biologically related continuities (and non-biologically defined substances which play a role, such as the idea that early biological beginnings may have occurred in clay).

The role in which geology, astronomy and other typically defined non-biological entities need to be involved in the listings because they too exhibit recurring patterns of human cognition. Again, as I have stated and alluded to many times, we need to distinguish what patterns are actually part of a substance or event, and those which are being imposed on them by predilections of human mental activity. If we consider that all perceptions are without a question those which are created... or made up... by the human mind as it is configured as a biologically based encephalization process, then we have not to go on but a system of educated guess-work. We do what we can do with that which is available to us to work with. Philosophically based or not. In some instances we can make a guess and test it for viability and at other times we may not have the present-day means of testing a guess, thus leaving it for some future time, place, and researcher(s) to prove, disprove or simply dismiss as being irrelevant. However, unless we bring the information to a point of academic or commercial interest, there may be little to no funding available for such a pursuit, as is the case for many different types of individually originated ideas.

And with respect to commercialization and the internet as a viable means of making some semblance of a social contact with different people who might not otherwise encounter one another, it should be noted that the examples which I portray and am using as an illustrative base to support my contentions, does not mean that the examples are to be construed as definitive accounts of what may be available for consideration. For example, while the previous page showed examples of "opolies" (monopoly, etc...), and I made a comment concerning the absence of some models, this does not mean such models are in fact not thought of by someone. The person or persons may simply have no interest in providing their views in a manner and means which I am able to come across in the constrained search parameters I use at any given moment. In other words, there may be examples of "opolies" which reference a number into the hundreds and thousands, but I have not found any. The simple lack of such on the internet or usage by some commercial effort should not be the rule-of-thumb one goes by in deciding whether or not someone somewhere has even considered such an option of thought. Likewise for any image or posted idea. Limitations of space and other considerations must be taken into account by giving the benefit of a doubt in order to maintain some semblance of an effort to remain open-minded.

As we examine more details from the timeline of evolution along a "threesological" gradient, one example is the origin of the tripartite brain. Did it proceed from a two-part that was preceded by a one-part brain as a 1-2-3 sequence, or was it a type of "shazam" (all at once) emergence to be explained by a 'punctuated' event? In searching for clues, I first came across the following around 1:06 AM (Wednesday 2nd, Oct.) as I begin typing again after yesterday's departure from the above due to pressing chores to be done:


The many different nervous systems found in bilaterally symmetric animals may indicate that the tripartite brain appeared several times during the course of bilaterian evolution. However, comparative developmental genetic evidence in arthropods, annelids, urochordates, and vertebrates suggests that the development of a tripartite brain is orchestrated by conserved molecular mechanisms. Similarities in the underlying genetic programs do not necessarily reflect a common origin of structures. Nevertheless, 3 lines of evidence support a monophyletic origin of the tripartite brain and possibly also an elongated central nervous system (CNS):

  1. Structural homology
  2. Character identity networks
  3. The functional equivalence of character identity genes

Monophyly of the brain also implies that the brain was secondarily reduced and lost multiple times during the course of evolution, leading to extant brainless bilaterians. The likelihood of secondary loss can be estimated by metazoan divergence times and through reconstructed cases such as limb loss in tetrapods or eye loss in fish. When scaled to molecular clock dates, monophyly of the tripartite brain indicates that existing brainless Bilateria had several hundred million years' time for the secondary modification and eventual loss of a primitive/ancestral brain and CNS. To corroborate this conjecture, ancestral character identity genes of living brainless Bilateria can be tested for their potential to substitute Drosophila or Mus homologs in tripartite brain development.

On the origin and evolution of the tripartite brain. by Frank Hirth
(PDF full article)

Tripartite brain evolution

The question I want to pose is why did the pattern return after it was dismissed... not once, but apparently several times? Why not persist in developing brainless life forms or life forms with a "mono-lateral" or a bilateral brain or a brain with more-than-three divisions? What is causing the recurrence of a tripartite structure not only in the brain, but other brain-induced perceptions which we illustrate as occurring in different subjects? Is the multiplicity of illustrated "threes" just an extension of the tripartite brain development? Indeed, no less, if the bilateral body plan is so very important as suggested by its recurrence, why not keep this design as an exclusive instead of diverging into a sequential development towards a "three" expression yet instead of continuing on from here, evolution "wants to" hang out around the three-zone? Is there something in the environment which predisposes biological processes to repeat a "three" development, thus suggesting the possibility that whatever is causing this may be vulnerable to disruption? Is language little more than an expressed dimension of biological activity such that the fluidity of words and combinations reflect processes of biology in its various developmental scenarios such as the extinction of a word or entire language is the extinction of a biological route of some process, some appendage or some species?

In any respect, I placed the question marked development of the tripartite brain onto the above time-line sketch in relation to the information presented in the article concerning the development of the Cnidarians at around 580 million years ago and are recognized as being trimorphic: (Many cnidarian species produce colonies that are single organisms composed of medusa-like or polyp-like zooids, or both [hence they are trimorphic].)

By placing the different developmental scenarios on a timeline with respect to enumeration, we get a holistic account that may help us to pinpoint what may have initiated biological processes to take on an exhibited 1-2-3 developmental exercise, though there are stops, starts, divergencies, reversals and punctuations, to which we might as well add the three character symbols of question marks, periods, and exclamation points as pictorial images of biological events.

In developing a timeline which reveals a different perspective than the typical ones being encountered, a typical one needs to be portrayed so as to make the comparison a bit more understood. The following example provides a general outline with the intent of illustrating some major occurrences, some of which describe a pattern-of-two, a pattern-of-three, or otherwise leaves an subtle, easy visible or difficult to recognize pattern to the imagination of the reader. In addition, please note that in the typical timeline there is no correlation being made as to the rate of the Earth's rotation. Hence, the idea of "rotation rate specificity" is not part of the current line of evolutionary thinking... but will eventually be included in the descent of future contemplations. Also, timelines dealing with evolution don't typically include underlying chemical process... even if much of it involving the precursors of evolutionary processes is speculative amounting from guesswork.

  1. 3.8 billion years ago? This is our current "best guess" for the beginning of life on Earth. It is distinctly possible that this date will change as more evidence comes to light. The first life may have developed in undersea alkaline vents, and was probably based on RNA rather than DNA. At some point far back in time, a common ancestor gave rise to two main groups of life: bacteria and archaea. How this happened, when, and in what order the different groups split, is still uncertain.

It is imperative that the reader take into account the environment as it may have been:

  • The color of the sky was not blue.
  • There was little no oxygen and the oxygen content increased over time, called the Great Oxidation Event, though one might use the initials "GOD" for Great Oxygen Development.
  • The intensity of the solar irradiation (or lack there of) must be taken into account.
  • The increased rotation rate of the Earth.
  • The close proximity of the Moon.
  • The salinity of the ocean.
  • ETC...

The list is brought up because I want to suggest that there may have been a definitive three-patterned environment event which influence the creation of the triplet code in DNA, and it is not (only) the result of some of some chemical interactions. With this stated, the fact that the Sun's three phases (moments) labeled as dawn- noon- dusk in conjunction with a two-patterned night/day sequencing, may have effected the expression of a triplet pattern like a branding iron effect during a period in which basic biological substrates where impressionable. In fact, when we look at life, we might want to think in terms of a "Rotation Rate Specificity", such that because different life forms occurred during different periods of time as the Rotation Rate of the Earth changed, this may mean humans can not live long when the rotation rate of the Earth slows to a given speed. As a reference: Rotation Rate page 1

  1. 3.5 billion years ago The oldest fossils of single-celled organisms date from this time.
  2. 3.46 billion years ago Some single-celled organisms may be feeding on methane by this time.
  3. 3.4 billion years ago Rock formations in Western Australia, that some researchers claim are fossilized microbes, date from this period.
  4. 3 billion years ago Viruses are present by this time, but they may be as old as life itself.
  5. 2.4 billion years ago The "great oxidation event". Supposedly, the poisonous waste produced by photosynthetic cyanobacteria – oxygen – starts to build up in the atmosphere. Dissolved oxygen makes the iron in the oceans "rust" and sink to the seafloor, forming striking banded iron formations.

Recently, though, some researchers have challenged this idea. They think cyanobacteria only evolved later, and that other bacteria oxidized the iron in the absence of oxygen. Yet others think that cyanobacteria began pumping out oxygen as early as 2.1 billion years ago, but that oxygen began to accumulate only due to some other factor, possibly a decline in methane-producing bacteria. Methane reacts with oxygen, removing it from the atmosphere, so fewer methane-belching bacteria would allow oxygen to build up.

  1. 2.3 billion years ago Earth freezes over in what may have been the first "snowball Earth", possibly as a result of a lack of volcanic activity. When the ice eventually melts, it indirectly leads to more oxygen being released into the atmosphere.
  2. 2.15 billion years ago First undisputed fossil evidence of cyanobacteria, and of photosynthesis: the ability to take in sunlight and carbon dioxide, and obtain energy, releasing oxygen as a by-product. There is some evidence for an earlier date for the beginning of photosynthesis, but it has been called into question.
  3. 2 billion years ago? Eukaryotic cells – cells with internal "organs" (known as organelles) – come into being. One key organelle is the nucleus: the control centre of the cell, in which the genes are stored in the form of DNA.
    • Eukaryotic cells evolved when one simple cell engulfed another, and the two lived together, more or less amicably – an example of "endosymbiosis". The engulfed bacteria eventually become mitochondria, which provide Eukaryotic cells with energy. The last common ancestor of all Eukaryotic cells had mitochondria – and had also developed sexual reproduction.
    • Later, Eukaryotic cells engulfed photosynthetic bacteria and formed a symbiotic relationship with them. The engulfed bacteria evolved into chloroplasts: the organelles that give green plants their colour and allow them to extract energy from sunlight.
    • Different lineages of Eukaryotic cells acquired chloroplasts in this way on at least three separate occasions, and one of the resulting cell lines went on to evolve into all green algae and green plants.
  4. 1.5 billion years ago? The Eukaryotes divide into three groups: the ancestors of modern plants, fungi and animals split into separate lineages, and evolve separately. We do not know in what order the three groups broke with each other. At this time they were probably all still single-celled organisms.
  5. 900 million years ago? The first multicellular life develops around this time.

It is unclear exactly how or why this happens, but one possibility is that single-celled organisms go through a stage similar to that of modern choanoflagellates: single-celled creatures that sometimes form colonies consisting of many individuals. Of all the single-celled organisms known to exist, choanoflagellates are the most closely related to multicellular animals, lending support to this theory.

  1. 800 million years ago The early multicellular animals undergo their first splits. First they divide into, essentially, the sponges and everything else – the latter being more formally known as the Eumetazoa.
  2. 780 million years ago A small group called the placozoa breaks away from the rest of the Eumetazoa. Placozoa are thin plate-like creatures about 1 millimetre across, and consist of only three layers of cells.It has been suggested that they may actually be the last common ancestor of all the animals.

Yale Peabody Museum's Trichloplax Genome Project distinguishes 4-named, 3 types of cells:

  1. Epithelial cells:
    1. Monociliated dorsal
    2. Ventral
  2. Gland cells: Ventral
  3. Fiber cells: Syncytial

The enigmatic animal phylum Placozoa holds a key position in the metazoan Tree of Life. A simple bauplan makes it appear to be the most basal metazoan known and genetic evidence also points to a position close to the last common metazoan ancestor. Trichoplax adhaerens is the only formally described species in the phylum to date, making the Placozoa the only monotypic phylum in the animal kingdom. (Trichoplax possesses a three-layered sandwich organization with morphologically different upper (protective) and lower (nutritive) epithelia. These two layers enclose a meshwork of connected fiber cells that are responsible for the changes in shape of Trichoplax.) [...According to Gottlieb Grell's studies, Trichoplax adhaerens was so different from all other known animal taxa that it deserved its own phylum. Grell named this phylum "Placozoa", from Bütschli's 'Placula" - a hypothetical two-layered and benthic 'Urmetazoon"...]

Global Diversity of the Placozoa by Michael Eitel, Hans-Jürgen Osigus, Rob DeSalle, and Bernd Schierwater

Information on the Internet

(List from: Placozoa- Trichoplacidae)

  1. 770 million years ago The planet freezes over again in another "snowball Earth".
  2. 730 million years ago The comb jellies (ctenophores) split from the other multicellular animals. Like the Cnidarians that will soon follow, they rely on water flowing through their body cavities to acquire oxygen and food.
  3. 680 million years ago The ancestor of Cnidarians (jellyfish and their relatives) breaks away from the other animals – though there is as yet no fossil evidence of what it looks like.
  4. 630 million years ago Around this time, some animals evolve bilateral symmetry for the first time: that is, they now have a defined top and bottom, as well as a front and back. Little is known about how this happened. However, small worms called Acoela may be the closest surviving relatives of the first ever bilateral animal. It seems likely that the first bilateral animal was a kind of worm. Vernanimalcula guizhouena, which dates from around 600 million years ago, may be the earliest bilateral animal found in the fossil record.
  5. 590 million years ago The Bilateria, those animals with bilateral symmetry, undergo a profound evolutionary split. They divide into the protostomes and deuterostomes.
    • The deuterostomes eventually include all the vertebrates, plus an outlier group called the Ambulacraria. The protostomes become all the arthropods (insects, spiders, crabs, shrimp and so forth), various types of worm, and the microscopic rotifers. Neither may seem like an obvious "group", but in fact the two can be distinguished by the way their embryos develop. The first hole that the embryo acquires, the blastopore, forms the anus in deuterostomes, but in protostomes it forms the mouth.
  6. 580 million years ago The earliest known fossils of Cnidarians, the group that includes jellyfish, sea anemones and corals, date to around this time – though the fossil evidence has been disputed.
  7. 575 million years ago Strange life forms known as the Ediacarans appear around this time and persist for about 33 million years.
  8. 570 million years ago A small group breaks away from the main group of deuterostomes, known as the Ambulacraria. This group eventually becomes the echinoderms (starfish, brittle stars and their relatives) and two worm-like families called the hemichordates and Xenoturbellida.
    • Another echinoderm, the sea lily, is thought to be the "missing link" between vertebrates (animals with backbones) and invertebrates (animals without backbones), a split that occurred around this time.
  9. 565 million years ago Fossilized animal trails suggest that some animals are moving under their own power.
  10. 540 million years ago As the first chordates – animals that have a backbone, or at least a primitive version of it – emerge among the deuterostomes, a surprising cousin branches off.
    • The sea squirts (tunicates) begin their history as tadpole-like chordates, but metamorphose partway through their lives into bottom-dwelling filter feeders that look rather like a bag of seawater anchored to a rock. Their larvae still look like tadpoles today, revealing their close relationship to backboned animals.
  11. 535 million years ago The Cambrian explosion begins, with many new body layouts appearing on the scene – though the seeming rapidity of the appearance of new life forms may simply be an illusion caused by a lack of older fossils.
  12. 530 million years ago The first true vertebrate – an animal with a backbone – appears. It probably evolves from a jawless fish that has a notochord, a stiff rod of cartilage, instead of a true backbone. The first vertebrate is probably quite like a lamprey, hagfish or lancelet.
    • Around the same time, the first clear fossils of trilobites appear. These invertebrates, which look like oversized wood-lice and grow to 70 centimetres in length, proliferate in the oceans for the next 200 million years.
  13. 520 million years ago Conodonts, another contender for the title of "earliest vertebrate", appear. They probably look like eels.
  14. 500 million years ago Fossil evidence shows that animals were exploring the land at this time. The first animals to do so were probably euthycarcinoids – thought to be the missing link between insects and crustaceans. Nectocaris pteryx, thought to be the oldest known ancestor of the cephalopods – the group that includes squid – lives around this time.
  15. 489 million years ago The Great Ordovician Biodiversification Event begins, leading to a great increase in diversity. Within each of the major groups of animals and plants, many new varieties appear.
  16. 465 million years ago Plants begin colonizing the land.
  17. 460 million years ago Fish split into two major groups: the bony fish and cartilaginous fish. The cartilaginous fish, as the name implies, have skeletons made of cartilage rather than the harder bone. They eventually include all the sharks, skates and rays.
  18. 440 million years ago The bony fish split into their two major groups: the lobe-finned fish with bones in their fleshy fins, and the ray-finned fish.
    • The lobe-finned fish eventually give rise to amphibians, reptiles, birds and mammals. The ray-finned fish thrive, and give rise to most fish species living today.
    • The common ancestor of lobe-finned and ray-finned fish probably has simple sacs that function as primitive lungs, allowing it to gulp air when oxygen levels in the water fall too low. In ray-finned fish, these sacs evolve into the swim bladder, which is used for controlling buoyancy.
  19. 425 million years ago The coelacanth, one of the most famous "living fossils" – species that have apparently not changed for millions of years – splits from the rest of the lobe-finned fish.
  20. 417 million years ago Lungfish, another legendary living fossil, follow the coelacanth by splitting from the other lobe-finned fish. Although they are unambiguously fish, complete with gills, lungfish have a pair of relatively sophisticated lungs, which are divided into numerous smaller air sacs to increase their surface area. These allow them to breathe out of water and thus to survive when the ponds they live in dry out.
  21. 400 million years ago The oldest known insect lives around this time. Some plants evolve woody stems.
  22. 397 million years ago The first four-legged animals, or tetrapods, evolve from intermediate species such as Tiktaalik, probably in shallow freshwater habitats. The tetrapods go on to conquer the land, and give rise to all amphibians, reptiles, birds and mammals.
  23. 385 million years ago The oldest fossilized tree dates from this period.
  24. 375 million years ago Tiktaalik, an intermediate between fish and four-legged land animals, lives around this time. The fleshy fins of its lungfish ancestors are evolving into limbs.
  25. 340 million years ago The first major split occurs in the tetrapods, with the amphibians branching off from the others.
  26. 310 million years ago Within the remaining tetrapods, the sauropsids and synapsids split from one another. The sauropsids include all the modern reptiles, plus the dinosaurs and birds. The first synapsids are also reptiles, but have distinctive jaws. They are sometimes called "mammal-like reptiles", and eventually evolve into the mammals.
  27. 320 to 250 million years ago The pelycosaurs, the first major group of synapsid animals, dominate the land. The most famous example is Dimetrodon, a large predatory "reptile" with a sail on its back. Despite appearances, Dimetrodon is not a dinosaur.
  28. 275 to 100 million years ago The therapsids, close cousins of the pelycosaurs, evolve alongside them and eventually replace them. The therapsids survive until the early Cretaceous, 100 million years ago. Well before that, a group of them called the cynodonts develops dog-like teeth and eventually evolves into the first mammals.
  29. 250 million years ago The Permian period ends with the greatest mass extinction in Earth"s history, wiping out great swathes of species, including the last of the trilobites.
    • As the ecosystem recovers, it undergoes a fundamental shift. Whereas before the synapsids (first the pelycosaurs, then the therapsids) dominated, the sauropsids now take over – most famously, in the form of dinosaurs. The ancestors of mammals survive as small, nocturnal creatures./li>
    • In the oceans, the ammonites, cousins of the modern nautilus and octopus, evolve around this time. Several groups of reptiles colonize the seas, developing into the great marine reptiles of the dinosaur era.
  30. 210 million years ago Bird-like footprints and a badly-preserved fossil called Protoavis suggest that some early dinosaurs are already evolving into birds at this time. This claim remains controversial.
  31. 200 million years ago As the Triassic period comes to an end, another mass extinction strikes, paving the way for the dinosaurs to take over from their sauropsid cousins.
    • Around the same time, proto-mammals evolve warm-bloodedness – the ability to maintain their internal temperature, regardless of the external conditions.
  32. 180 million years ago The first split occurs in the early mammal population. The monotremes, a group of mammals that lay eggs rather than giving birth to live young, break apart from the others. Few monotremes survive today: they include the duck-billed platypus and the echidnas.
  33. 168 million years ago A half-feathered, flightless dinosaur called Epidexipteryx, which may be an early step on the road to birds, lives in China.
  34. 150 million years ago Archaeopteryx, the famous "first bird", lives in Europe.
  35. 140 million years ago Around this time, placental mammals split from their cousins the marsupials. These mammals, like the modern kangaroo, that give birth when their young are still very small, but nourish them in a pouch for the first few weeks or months of their lives.
    • The majority of modern marsupials live in Australia, but they reach it by an extremely roundabout route. Arising in south-east Asia, they spread into north America (which was attached to Asia at the time), then to south America and Antarctica, before making the final journey to Australia about 50 million years ago.
  36. 131 million years ago Eoconfuciusornis, a bird rather more advanced than Archaeopteryx, lives in China.
  37. 130 million years ago The first flowering plants emerge, following a period of rapid evolution.
  38. 105-85 million years ago The placental mammals split into their four major groups: the laurasiatheres (a hugely diverse group including all the hoofed mammals, whales, bats, and dogs), euarchontoglires (primates, rodents and others), Xenarthra (including anteaters and armadillos) and afrotheres (elephants, aardvarks and others). Quite how these splits occurred is unclear at present.
  39. 100 million years ago The Cretaceous dinosaurs reach their peak in size. The giant sauropod Argentinosaurus, believed to be the largest land animal in Earth"s history, lives around this time.
  40. 93 million years ago The oceans become starved of oxygen, possibly due to a huge underwater volcanic eruption. Twenty-seven per cent of marine invertebrates are wiped out.
  41. 75 million years ago The ancestors of modern primates split from the ancestors of modern rodents and lagomorphs (rabbits, hares and pikas). The rodents go on to be astonishingly successful, eventually making up around 40 per cent of modern mammal species.
  42. 70 million years ago Grasses evolve – though it will be several million years before the vast open grasslands appear.
  43. 65 million years ago The Cretaceous-Tertiary (K/T) extinction wipes out a swathe of species, including all the giant reptiles: the dinosaurs, pterosaurs, ichthyosaurs and plesiosaurs. The ammonites are also wiped out. The extinction clears the way for the mammals, which go on to dominate the planet.
  44. 63 million years ago The primates split into two groups, known as the haplorrhines (dry-nosed primates) and the strepsirrhines (wet-nosed primates). The strepsirrhines eventually become the modern lemurs and aye-ayes, while the haplorrhines develop into monkeys and apes – and humans.
  45. 58 million years ago The tarsier, a primate with enormous eyes to help it see at night, splits from the rest of the haplorrhines: the first to do so.
  46. 55 million years ago The Palaeocene/Eocene extinction. A sudden rise in greenhouse gases sends temperatures soaring and transforms the planet, wiping out many species in the depths of the sea – though sparing species in shallow seas and on land.
  47. 50 million years ago Artiodactyls, which look like a cross between a wolf and a tapir, begin evolving into whales.
  48. 48 million years ago Indohyus, another possible ancestor of whales and dolphins, lives in India.
  49. 47 million years ago The famous fossilized primate known as "Ida" lives in northern Europe. Early whales called protocetids live in shallow seas, returning to land to give birth.
  50. 40 million years ago New World monkeys become the first simians (higher primates) to diverge from the rest of the group, colonising South America.
  51. 25 million years ago Apes split from the Old World monkeys.
  52. 18 million years ago Gibbons become the first ape to split from the others.
  53. 14 million years ago Orang-utans branch off from the other great apes, spreading across southern Asia while their cousins remain in Africa.
  54. 7 million years ago Gorillas branch off from the other great apes.
  55. 6 million years ago Humans diverge from their closest relatives; the chimpanzees and bonobos.
    • Shortly afterwards, hominins begin walking on two legs. See our interactive timeline of human evolution for the full story of how modern humans developed.
  56. 2 million years ago A 700-kilogram rodent called Josephoartigasia monesi lives in South America. It is the largest rodent known to have lived, displacing the previous record holder: a giant guinea pig.

New Scientist: Timeline, The evolution of life By Michael Marshall, 14 July 2009

Origination date: Tuesday, October 1st, 2019... 4:58 AM
Initial Posting: Thursday, October 3rd, 2019... 11:49 AM
Updated Posting: Friday, January 20th, 2023... 12:15 PM

Your Questions, Comments or Additional Information are welcomed:
Herb O. Buckland