Dinosaurs and their Descendents 1 - What You Need to Know FIRST

` This may surprise you, but as a small child, I was not very interested in dinosaurs, being that I didn't really think they existed. "How could those be animals?" I would think.
` True, paintings at the time of large, rubbery beasts slugging it out like Gojira and Megalon didn't help matters. If you've read other parts of this blog, what may not surprise you is that, little did I suspect, I spoke DadEnglish. In DadEnglish, life = 'miserable limbo', extinct = 'bunch of bones', and the past = 'a time that didn't exist'.
` Of course, that's a whole other DadStory...
` However, it is worth noting that one word of DadEnglish was; Bird = 'annoying, boring animal': another was; Dinosaur = 'pile of bones that was warm-blooded, dammit!' I largely ignored his rantings about dinosaurs and continued to not really think they existed. I forget why.

` After being able to study the whole matter for several years, my perceptions are now; Bird = 'short-tailed dinosaur'; and Dinosaur = 'a group of archosaurian reptiles existing from the late Triassic to right now!'

` Or, as Ascitu-saurus sums it up:

... ,--=@ + ..............< "Hooray! We're not dead!"...................
..."'`**") # ............................................................................
.............` &. "..------====_-_-_ - ------==<,=<:<:<:<+=~...
............... zz . >>>? 7) 5 ...................................``````` ``` ``...
.................~$j> ^^/%y ..........................................................
................../# ........:4 .............................................................
.................^R..........9 ...........................................................
........................~^JfZ .............................................................

` I am sure this is not surprising to some, but I can understand why others would be confused and even outraged over the matter. For anyone who is interested, I have now made the original text more suitable for laymen so that non-experts (like Phil!) can follow along without getting brain cramps. I am confident that I will be able to explain exactly why mainstream scientists classify birds as theropod dinosaurs (and why... um... others... do not).

` Too see my point, all you have to do is ask: 'No, really, what is a bird?' Considering all the birdlike fossils that exist, this is a much more complicated question than most people would expect, as you will see!
` A different way one could word this question is: "In a family tree of animals, how could birds fit in?" I will explain this thoroughly in time, hopefully without being too overwhelming.
` For visual reference I have posted a cladogram - which makes a good family tree, since it works by sorting out the anatomical similarities and differences of any number of life-forms. The names of the animals that are most similar have the least amount of line between them.
` Mine here is actually based on one made by Richard O. Prum that appeared in the January 2002 issue of The Auk (journal of the American Ornithologists' Union).

` By the way, I figured out that I need to put periods in the blank spaces to hold this together - so ignoring those, you can see that all of these dinosaur groups on the right are part of a larger group called the coelurosaurs (see-LOO-roe-sores), as that name appears at the base. It means 'hollow reptiles', in reference to their very birdlike, air-filled bones.

(From other.........................................../....Compsognathids
theropods)...........,---------------------|.like *Sinosauropteryx
|...........................|....................................................................
|...........................|............................_______|.Alvarezaurids,
|...........................|............................|.............|..like *Shuvuuia
|...........................|......___________|.......................................
`-Coelurosaurs......../.......................|.....,-----|Ornithomimids
|........................./.........................|__|..................................
|......................../................................|_|..Therizinosaurids,
|...................../....................................|.like *Beipiaosaurus
Maniraptors'.......................................................................
|..........._______________________|Tyrannosaurids,
|..........|.......................................................like *Dilong
|..........|..........................................................................
|..........|........___________________|.....Oviraptorids,
`-------|.......|....................................|.like #Caudipteryx
|........|.................................................................
|.........|..........,----------------------|Troodontids
`-----|...........|......................................................
|.........|.................../...Dromaeosaurs, like
|.........|..................|......*Sinornithosaurus,
|........,`-----------|.......*Microraptor, and
`-------|...................|____.......*(Unnamed)
|.......................................................
|................,--------#Archaeopteryx
|________|......................................
|......,--#Confuciusornis
|__|...............................
|......#Enantiornithines
`--|..............................
`------#Euornithes
like modern birds

` (Note: The groups I am focusing on the most here are: Theropods > Coelurosaurs > Maniraptors > Birds and Dromaeosaurs.)

` As you can see, the coelurosaurs evolved in many directions: Sinosauropteryx (SYNE-oh-sawr-OP-ter-icks) evolved off in one direction, as indicated by the dashes. The near-complete specimens of this small animal tell us that it looked much like modern poultry - except its tail was ridiculously long, and it had a massive, long-clawed thumb.
` The asterick (*) by its name indicates that clear fossil imprints show Sinosauropteryx had primitively-structured feathers. I'll get to those later.
` All the other coelurosaurs shown here are on a completely different 'branch' of the tree, belonging to a sub-group called the maniraptors (MAN-i-rap-tors). It means 'prey-grabbing hands' because many of these animals had long arms with flexible wrists, and even opposable 'thumbs' (except for certain ones like Tyrannosaurus).
` These are the most birdlike dinosaurs, and though modern birds are understandably not usually known for having grasping hands, they used to be the norm for tens of millions of years.
` Note that by the individual animals' names are more astericks and also pound signs (#), which indicate that those species were found with more complex feathers just like those of modern birds!

` So, how did they figure this cladogram out in the first place?

` It's been so far about a hundred and fifty years since Thomas Henry Huxley noticed that birds have much in common with reptiles - especially coelurosaurs! - though most features are not necessarily obvious.
` For example, birds have fused, Velociraptor-like fingers, though in most species, they are not visible from the outside. Archaeopteryx (ar-kee-OP-ter-icks), a flying, 'feather-bearing animal' found in the 1800s looked similar to modern birds, yet its 'primitive' characteristics were much more exaggerated - most noted are the teeth, the clawed 'dinosaur' hands, and the long tail. In fact, one Archaeopteryx specimen with very poorly-preserved feathers had been - for a century! - thought to be a tiny coelurosaur called Compsognathus! (It wasn't looked at very often.)

` It is no wonder that for decades, scientists would ask: 'Was Huxley really onto something?'

` Now that paleontologists understand the fossil record in much better detail, it has been becoming increasingly clear that one can find consistently in just one group of animals over 100 anatomical features that otherwise only birds are known to have. (Other reptiles don't come close!)
` These animals are called theropods (THER-o-pods), which means 'beast feet' - though a more accurate name would be 'bird feet'. This group includes all your two-legged, meat-eating dinosaurs, such as coelurosaurs, as well as others people may generally be familiar with, such as Coelophysis, Dilophosaurus, Allosaurus, Ceratosaurus, Spinosaurus, and Carnotaurus (which can be found elsewhere on the theropod 'family tree').

` So, yes, to make things most abundantly clear, maniraptors are a group of coelurosaur dinosaurs, and coelurosaurs are in turn a group of theropod dinosaurs. (See cladogram.)

` Now, some maniraptors are probably more familar than others - for example, tyrannosaurids include the most famous species of dinosaur, Tyrannosaurus rex, hence the name. They are known for their unusually short arms and distinctive, muscular heads.
` Like other maniraptors, tyrannosaurs' eyes face forwards, and the snout has a distinct shape, starting off narrower than the rest of the head. (Other large predators like Allosaurus and Megalosaurus, which are not even coelurosaurs - much less maniraptors - can be distinguished at a glance by their wedge-shaped heads and sideways-facing eyes.)

` Even more birdlike maniraptors include oviraptorids (OH-vee-rap-tor-ids), named for Oviraptor, or 'egg-theif', as the first one ever found was thought to be stealing from a Protoceratops nest.
` It turns out that the 'Protoceratops' eggs had baby Oviraptors in them, but the name had already stuck and ruined it for the rest of the group. (We now know that it is common for these animals to die and be preserved on their nests. Strange, but true.)
` Oviraptorids are most recognizable for their very strange beaks - almost like a parrot's - which were very strong and probably used for crushing nuts (not eggs!).

` As you can see on the cladogram, there are two groups of dinosaurs in particular that are most closely related to birds. Troodontids (TROE-oh-don-tids) were named for what was - in the distant past - thought to be a monitor lizard-type tooth called Troodon ('wounding tooth'). Today we know that Troodon was a very slender predatory dinosaur that had a small, retractable sickle claw on its second toe, and the largest brain-to-body ratio of any dinosaur.

` However, birds are most closely linked with the more famous sickle-clawed dinosaurs known as dromaeosaurs (DROME-ee-o-saurs), or 'swiftly-running reptiles', which had fairly large brains and an even more impressive hooked claw than troodontids.
` One of these listed on the cladogram is the tiny Microraptor, which is best known for both its Archaeopteryx-type wings and its strange 'leg-wings', which apparently were used in conjunction to clumsily flutter through the treetops.
` Probably a more familiar example of a dromaeosaur would be Velociraptor - which James T. Kirkland (a paleontologist you may have heard of) once assured me was not nearly as large and panic-inducing as the ones depicted in Stephen Spielberg's blockbuster movie, Jurassic Park.
` Also, said Kirkland, Spielberg got the distinctive shape of the great claw wrong (as he handed me an example from one of the film's animatronic Velociraptors) - a real dromaeosaur claw is actually thin and flattened like a blade (not oval in cross-section), which is a shape best suited for slashing through such things as plant-eating dinosaurs.
` I should note here that primitive birds (including Archaeopteryx) are also known to have a raised second toe and foot claw similar to that of dromaeosaurs and troodontids.


` What's of interest here, though, is not the differences between the groups, but the similarities that link these animals to birds - which are numerous. In fact, since more and more dromaeosaur-like birds (and bird-like dromaeosaurs, etc) are being found, paleontologists are becoming hard-pressed to find which exact characteristics actually define a bird and which do not!
` Here, I shall go over just a few basic features in various parts of the anatomy that can be seen in both true birds and other theropods (particularly maniraptors). In other words, the following traits are definitely not defining characteristics for birds alone:

Air-filled bones: Since the beginning of dinosaurs, theropods in general (not just the coelurosaurs) have had the distinctive pneumatic (air-filled) chambers in vertebrae, leg bones, and ribs - though not all species.
` The reason for this was to add speed and agility by reducing weight and increasing strength, and as the same chambers are seen in the most birdlike of dinosaurs, this is the generally-accepted origin of these chambers in birds. (Today, many birds have also evolved away from this tendency - very tiny birds have light enough bones as it is, and diving birds could certainly do with less buoyancy, so accordingly their bones have no air sacs.)

*

Legs: A maniraptor typically has a four-toed foot, with the first digit (our 'big' toe) being the smallest and not used in supporting the animal's weight. The foot-bones (metatarsals) are elongated as well, meaning the animals has very long feet, good for leverage and speed. Same for finches and Velociraptors, the ankle is hingelike and can only move back and forth.
` And though it's a basic characteristic of all dinosaurs, it is still significant that maniraptors also walk on their toes while keeping their legs beneath them. It is hard to find a reptile that is not a dinosaur that does this, except for the ancestors of dinosaurs. Therefore, it is logical to say that birds have gotten their specific type of dinosaur-legs from maniraptorian dinosaurs.

*

Pelvis: In most maniraptors - like dromaeosaurs and primitive birds - the two bottom pelvic bones, the pubes (yes, they're really called that!), point backwards, with a little 'boot' at the end. (Most theropods have forward-pointing pubes.) This arrangement frees the tail from being joined up with the legs, causing the gait to be even more like that of birds than other theropods.
` Also, at least five vertebrae are fused into a mass above the pelvis in these animals - in today's birds, quite a good portion of the spine is fused into one bone.

*

Tail: Though the tail of many maniraptors may appear quite long, it is actually reduced, with fewer vertebrae than most other dinosaurs, and all but the first part is stiffened to some degree.
` Archaeopteryx had 22 tail vertebrae (which isn't much for a maniraptor), while modern birds (and some oviraptoroids), have a fused stump called a pygostyle. (Humans have something similar, the coccyx or 'tailbone', though of course it does not protrude from the body.)

*

Neck: Something else dinosaurs have is some degree of an S-shaped neck, and therefore, maniraptors would have to have gotten this s-shape from more primitive dinosaurs. The particular type of strongly-curved, air-sac-filled neck vertebrae that birdlike maniraptors have matches up the best to those of birds.

*

Shoulder: There is a large breastbone, the collarbones are fused to form a furcula, or 'wishbone', and the shoulder blades are 'strap-like.' This arrangement provides a lot of strength while helping the arms to move at a wide range of angles suited to grabbing prey, climbing trees, or flapping in the figure-eight pattern birds need to fly.
` This tells us that (unless all maniraptors evolved from a flying ancestor) birds evolved the range of motion needed for flight before they even got off the ground.

*

Arms: Maniraptors typically have elongated arms - especially the forelimbs - and the hands are larger than the feet. Though Tyrannosaurus' arms were tiny (to reduce weight in the front of the body), other maniraptors such as Oviraptor, Troodon, and Velociraptor had very long arms that needed to be kept folded up and out of the way - this is why they are sometimes referred to as 'knuckle-draggers.'
` Of course, birds that fly need similarly long arms to use as wings - which also fold about the same way.
` Three is the usual number of fingers for a maniraptor, and these are usually long, with opposable 'thumbs'. Tree-climbing dromaeosaurs - as well as primitive birds - used such clawed hands for holding onto tree branches.
` Also essential for grabbing prey and flying is a rather flexible wrist. Only in maniraptors and primitive birds can we find the semilunate carpal, or 'half-moon-shaped wrist bone', which allows the wrist to bend in such a way that capturing prey or flapping is possible.

*

Skull: Maniraptors - especially small ones - also have birdlike, insanely huge eye-openings (orbits) in the skull. (Comparing the bones of the eyeball themselves - the sclerotic ring - also show that the eyes were of similar sizes.)
` Also, the air-filled sinuses of birds are expanded, as well as those of other maniraptors - and in other dinosaurs and crocodiles, too. Evidently, this characteristic had originated before dinosaurs had even evolved.
` Maniraptors also have a secondary bony palate in order to breathe through the nostrils with the mouth closed, a useful feature that birds have today. (Yes, mammals do too, and our high metabolism might have something to do with it.)
` The teeth are all about the same type throughout the mouth, and are constricted or 'waisted' between the crown and the root.

*

Feathers: Impressions of honest-to-goodness (modern and primitive) feathers have been found in rocks around various kinds of dead coelurosaurs, several of which are listed on the cladogram. Some of them resemble down feathers, which consist of soft little strands called barbs extending from a single root. Others, (which may be also attached to the same dinosaur!), consist of barbs branching off a rachis (center spine), which looks exactly like a contour feather from a modern bird!
` Some nonavian ('non-bird') dinosaur feathers are also known to have barbules, which are like little branches protruding from the barbs to 'zip' them together, and birds also have these structures. Coelurosaur feathers thought not to have barbules are called 'primitive' feathers or 'protofeathers', since birds - modern or ancient! - are not known to have ever had barbule-less feathers.
` For further description of feathered dinosaur species... that's coming.

*

Eggshell: There are three basic types of dinosaur eggshell, and the one called the ornithoid ('bird-type') is found only in theropods. It differs greatly from even those of other dinosaurs, since the very innermost layer, where the basic units of shell can be seen as discrete 'bumps', is much thinner. The next layer is a mass of biocrystaline material, and at the very smallest level, it is spongy and... sorry, am I losing you?
` Anyhow, this structure is basically the same as that of birds. As for other reptile eggshells - including crocodiles - they are markedly different from those of all dinosaurs, though some of this is hard to see without an electron microscope.

` The details go on, really, but I figure that's plenty. As Dr. Kevin Padian noted in Nature, most of what used to define Aves (birds) is now known to be present in theropod dinosaurs! Consequently, if you find bits of a dinosaur skeleton that has many of these characteristics, yet nothing that particularly distinguishes it as either a bird or another maniraptor, you would not be able to tell if it was a bird or not!

` I can say that this is certainly a much different picture than what scientists began speculating about soon after Huxley's musings - that the ancestors of birds were most likely close relatives of crocodiles (Walker) or so-called 'thecodonts' (Heilman).
` This view didn't really begin to change until Dr. John Ostrom described a large, powerful dromaeosaur known as Deinonychus antirrhopus and its striking resemblance to little Archaeopteryx. There was a lot of controvery about this at first, though most of it soon died down as more data surfaced.
` In the mid-eighties, Dr. Gauthier used a revolutionary type of analysis - cladistics - to produce (of course!) a cladogram showing the place of birds in the theropod family tree (linked by 130 shared characteristics). Since then, independent analyses have repeatedly shown that he is indeed correct - the more modern cladogram shown above still echoes his results.


` I will point out to you that what the cladogram demonstrates is not that birds evolved from dromaeosaurs like Velociraptor - which is a common misconception - but are a 'sister' group to them. (In fact, they probably evolved around the same time.) Luckily, it's simple enough to explain...

248---Triassic---213----------Jurassic----------144--------------Cretaceous--------------65

` This timeline-doohickey basically shows the three periods of the Mesozoic Era, also known as the 'Age of Reptiles', or sometimes 'When Dinosaurs Ruled'. (Though, as there are a lot more species of birds than mammals today, I'd say they're still doing a pretty good job!) The numbers indicate how many millions of years have passed since the beginning and end of each period.

` Dinosaurs and mammals both evolved around the end of the Triassic Period, which concluded in a global catastrophe that resulted in about 90% of all living things going extinct. With all the dominant, medium-to large-sized land animals now dead, the dinosaurs apparently managed to fill that niche the fastest.
` Small theropods, such as the long, sinuous Coelophysis (SEE-loo-FY-sis), survived the catastrophe, and probably through superior agility and speed, were finally able to evolve into something new. By 150 million years ago (in the Jurassic Period) theropods had diversified into an amazing assortment of forms, from large brutes like Allosaurus, to primitive birds like Archaeopteryx.
` After this time is actually when most other types of maniraptors have been discovered from! Not surprisingly, the more primitive species of wildly different maniraptors are more similar to primitive birds than are later forms:
` For example, early tyrannosaurs resembled other nondescript, birdlike dinosaurs with three fingers; later on, the more derived forms had large, distinct, muscular heads and tiny arms (evidently they found jaws to be more useful).
` Also, early therizinosaurs seem to have been relatively fast-moving, partially predatory dinosaurs with rather long necks; later forms used all four of their toes for supporting their weight (instead of only three), and were apparently bulky plant-eaters with small heads and very long arms.
` Similarly, the earliest-known dromaeosaurs were overall quite small and most birdlike; though in the Late Cretaceous, the 26-foot-long Megaraptor was about twice as heavy as a polar bear, using toe-claws over fifteen inches in length to slash through the hide and muscle of such prey as duckbilled dinosaurs. (Other Late Cretaceous dromaeosaurs - like Velociraptor species - were coyote- to wolf-sized.)

` The reason for this, paleontologists concur, is because all maniraptors (which of course includes birds) evolved from a small coelurosaur around the Early Jurassic. Representative of their kinds, Tyrannosaurus, Therizinosaurus, and Dromaeosaurus - which don't seem to resemble one another at first graze - actually bear the unmistakeable stamp of having descended from a small birdlike dinosaur.
` Tyrannosaurus grew into a large-headed, tiny-armed form; Therizinosaurus grew into a large-armed, tiny-headed form; and Dromaeosaurus had a special second toe for slashing; yet all three are known to have descended from earlier dinosaurs that resembled one another more closely.
` And those dinosaurs must have in turn derived from one species - hence the term 'common ancestry'. We just don't know what that species is yet.
` Dromaeosaurs, then, shared a more recent common ancestor with birds - this one being not only a coelurosaur, but one of the maniraptors - perhaps one of the first animals with such a feature as the raised second toe-claw. The early fossil record of dromaeosaurs and Jurassic-aged birds is relatively sketchy, so it's hard to say exactly when this animal could have lived.
` Basically, it is most likely that dromaeosaurs and birds are 'sister' groups - the common ancestor being the 'mother'. One is generally thought not to have descended from the other, though it's hard to say. I wonder though, if birds could have come from the first dromaeosaurs or dromaeosaurs could actually be flightess versions of very primitive, Archaeopteryx-like birds? I don't know if anyone knows enough about this to be able to say.

` Any way you slice it, though, it's evident that birds are actually but one type of maniraptor (and Oviraptor was another). And maniraptors are coelurosaurs, which means... birds are a type of coelurosaur! And coelurosaurs are theropods, which means... birds are also a type of theropod. And theropods are a type of dinosaur, which means... birds are a type of dinosaur!
` An eagle is every bit as much a dinosaur as a Tyrannosaurus! It's just that the bird lineage happened to survive past 65 million years ago, while all the other lineages currently can only help us understand the past in the form of fossils (or contribute to global warming in the form of fossil fuels).


Doubts?

` No mainstream biologist really doubts anymore that birds are a type of dinosaur - it is clear enough that it is the case - but you've probably heard some others in the media who do. Why?
` Consider... this is the media we're talking about. News stories on television or in the paper for example, in order to draw more people in, are known to create controversy. I'm sure you've at least gotten that idea by now.

` The idea of 'objective journalism' often means that two sides are presented - whether they are equal or not - and the viewer or reader is left to decide which is best. In reality, there may be more than two sides to such an issue, or there may be only one, and if there is only one, an alternate 'side' may be added for contrast - in fact, some will even go so far as to completely make up another one!
` I'm sure many of you are familiar with this - especially in politics - because if someone in the news tells you what to think without offering any other choice, some complain that this is a biased opinion.

` In the case for 'dinosaurs are not birds', the 'alternative view' itself is not objective - the scientists who advocate this, while they technically are scientists, do not seem to have studied everything relevant or considered all data.
` Most of the dinosaurologists and ornithologists who contend that birds are dinosaurs have been studying this in more detail, and that's why they don't argue about the idea in general (though they may have different opinions about precisely which maniraptors birds evolved from, as this is still up in the air).

` But if they say that birds (like Archaeopteryx) are not dinosaurs, then what is it that they are saying that birds are? Generally, this answer is 'thecodonts.' What is a thecodont? Frankly, I thought I knew, but I'm not so sure anymore - there is more than one definition!
` It's possible that here the word may refer to various reptiles that were not dinosaurs or crocodiles or pterosaurs ('pterodactyls') but other types related to them, thrown together into one group. In any case, paleontologists generally do not use the word anymore because it isn't precisely useful in practice.

` Some of their proposed 'thecodont' species most closely linked with birds include Longisquama - a small, sprawling reptile with five digits that resembled a lizard more than it did Archaeopteryx. I should note that Archaeopteryx is much more similar to a dromaeosaur than it is to a modern bird - but people who say that 'dinosaurs are not birds' don't dispute that Archaeopteryx is also an early type of bird!
` Why would anyone pick Longisquama? These people claim that feathers most likely evolved for gliding and not insulation, and Longisquama had a few, very long structures of some sort that were much thicker than a feather and had a branched, feather-like pattern on the surface. Just what these structures actually were and what their function was is anybody's guess. (Display? Temperature regulation?)

` Another primitive form said to be related to the ancestors of birds was Megalancosaurus, an air-sac-boned, tree-climbing reptile which had a prehensile tail and long limbs with five-digit hands and feet that looked kind of like those of tree-marsupials and chameleons.
` Why? They reason; how could a bird evolve from an animal that lived on the ground? Long story short; Megalancosaurus' shoulder blades and a few other things were more birdlike than accepted bird-relatives (probably coincidentally) - but most other things about it were much less birdlike than any theropod!
` Also, it's possible that the animal used its long legs to support a gliding membrane, which means it could have evolved into a flying animal - though I would guess that if it had, it would have had membrane-wings like a bat!
` (Another animal called Sharovipteryx, for example, was a gliding reptile related to the ancestors of pterosaurs, which also had membranous wings. Sharovipteryx, however, used its hind legs instead of its front limbs for gliding, but you get the point.)

` I don't disagree that birds most likely evolved from a gliding, tree-climber. But considering that if dromaeosaurs had been discovered first and if Archaeopteryx was not known to have any feathers at all, it would have probably been thought of as a crow-sized, non-flying, distant cousin of Velociraptor that may have climbed trees.
` Something that would be fitting to name... Scuiraptor ('squirrel-raptor') or something. Their skeletons are that similar.
` But did dromaeosaurs climb trees? Well, Epidendrosaurus is a good candidate. It had a very long middle finger - perhaps for digging at grubs the way an aye-aye lemur does.
` Another dromaeosaur called Microraptor climbed trees as well, and it also had flight feathers covering its arms, legs, and tail. It could probably weakly fly or at least glide pretty well, and it would have been forgivable to confuse it with one of the first birds.
` While these animals lived alongside primitive birds, it is reasonable to suggest that these birds shared a common ancestor with them. Perhaps the ancestor resembled a tree-dromaeosaur, or perhaps it was a small, ground-living dinosaur. In the future, this picture will probably become clearer, but so far there isn't a whole lot of fossils lighting the way - very small animals only preserve well under special conditions.


` Well, I think that about does it for the introduction. I'll have more to write about birdlike dinosaurs, plus the evolution of feathers, the evolution of flight, and more of this 'controversy' found in media for the general public. That can be found in Part II.