Glires and Euarchontoglires

Several times I’ve mentioned some similarities between people and Bunny Rabbits and suggested that we must have a common ancestor not too far back. Further than the primate divide, but less than the deer / horse / bunny division.

Well, I finally got to look for it. The clade (group) is called “Glires”.

Rabbits and people can both eat onions. For many other herbivores, they are toxic.

Rabbits have a caecum that acts as a fermentation pouch. Like the stomachs of cows and sheep, but after the stomach and small intestine instead of in front. We have an appendix that is a ‘no longer used’ version of the same kind of intestinal fermentation pouch. (Some folks have postulated that the appendix may actually make some vitamins for us and might not be completely unused, thus the quotes).

There are other similarities, but those are two that stand out.

For a general and non-technical description:

http://www.rabbit.org/journal/3-3/digestibility.html

For a more technical version:

The rabbit’s caecum is the largest organ in the digestive tract and it develops over about 1 month from birth to be truly functional. Initially young rabbits depend for their nutrition on milk which is high in fat and protein but contains only small amounts of lactose. The C8 and C10 fatty acids in milk fat are bacteriostatic and protect the young animal from invasion by detrimental organisms. As milk intake diminishes towards weaning the organisms that develop in the gastrointestinal tract particularly in the caecum depend on the type of carbohydrate and the protein flow into the caecum. Recent research has demonstrated an adverse effect of high protein diets on survival of rabbits after weaning and throughout the fattening period.

The rabbit has the ability, through specialized musculature of the large intestine, to direct slowly fermented fibrous feed into the colon for excretion in the hard faeces. The same mechanism separates small particles (more digestible fiber) and soluble components of digesta leaving the ileum into the caecum where it remains in a buffered medium supporting bacterial growth. The rabbit quickly “sieves” indigestible or slowly fermentable fibers which would slow its feed intake were they to enter the caecum. Hard faeces are produced some 4 hours after a meal.

Later the bunny will excrete a fermented pellet mass and eat it. This second pass lets them get a lot more nutrients from plant food along with a variety of vitamins as fermentation products. This looks like they are eating their own poo, but it’s a very important process. It also makes them non-halal, something for which rabbits are undoubtedly very grateful ;-)

So I’d wondered just how far back up stream we had to go to find a common ancestor / branching point, and who else might be in this clad with humans, primates, and rabbits (lagomorphs)? As the labomorphs were only recently divided from the rodents, I was pretty sure we’d be lumped in with rats and mice, too; but look at most politicians and that’s pretty clear ;-) The division is due to the unique teeth of bunnies. Rodents have 4 front teeth, bunnies have six. The top set has two in line, front to rear, in each of the usual two incisor locations. The lower incisors are inserted between the two upper set and make a very nice snipping device.

But who else?

http://en.wikipedia.org/wiki/Glires

This clade joins the rodents and the bunnies. We join them just one more step up.

Glires (Latin glīrēs, dormice) is a clade (sometimes ranked as grandorder) consisting of rodents and lagomorphs (rabbits, hares, and pikas). This hypothesis that these form a monophyletic group has been long debated based on morphological evidence, although recent morphological studies strongly support monophyly of Glires (Meng and Wyss, 2001; Meng et al., 2003). In particular, the discovery of new fossil material of basal members of Glires, particularly the genera Mimotona, Gomphos, Heomys, Matutinia, Rhombomylus, and Sinomylus, has helped to bridge the gap between more typical rodents and lagomorphs (Meng et al., 2003; Asher et al., 2005). Data based on nuclear DNA support Glires as a sister of Euarchonta to form Euarchontoglires (Murphy et al. and Madsen et al. 2001), but some genetic data from both nuclear and mitochondrial DNA have been less supportive (Arnason et al. 2002). A study investigating retrotransposon presence/absence data unambiguously supports the Glires hypothesis (Kriegs et al. 2007).

So what is one step up? I mention glires as the next step up is Euarchontoglires or glires with a modifier in front…

Euarchontoglires (synonymous with Supraprimates) is a clade of mammals, the living members of which are rodents, lagomorphs, treeshrews, colugos and primates (including humans).

Yes, we and the other primates are more closely related to ‘treeshrews’ and ‘colugos’ (whatever they are…) than to bunnies and rodents, but that’s not really all that big a divide. Far far away are things like cats, dogs, horses, elephants, etc. etc.

The Euarchontoglires clade is based on DNA sequence analyses and retrotransposon presence/absence data, combining the Glires clade, which consists of Rodentia and Lagomorpha, with that of Euarchonta, a clade consisting of Scandentia, Primates (which includes humans) and Dermoptera.

Euarchontoglires is now recognized as one of four major groups within Eutheria (containing placental mammals). These four clades are usually discussed without a Linnaean rank, but has been assigned the rank of cohort or magnorder, and superorder. Relations within the four cohorts, Euarchontoglires, Xenarthra, Laurasiatheria, and Afrotheria, and the identity of the placental root, remain somewhat controversial.

Euarchontoglires probably split from the Laurasiatheria sister group about 85 to 95 million years ago during the Cretaceous, developing in the Laurasian island group which would later become Europe. This hypothesis is supported by fossil as well as molecular evidence. The clade of Euarchontoglires and Laurasiatheria is recognized as Boreoeutheria.

Have I mentioned lately that the shift from Linnaean naming to cladistics was underway when I was in college, and it is the reason that I decided not to go into anything that required learning cladistic naming conventions? I was not going to learn one whole set of naming system just to throw it all out and learn a new one… ;-)

At any rate, what are these things?

Scandentia are the treeshrews.

The treeshrews (or tree shrews or banxrings) are small mammals native to the tropical forests of Southeast Asia. They make up the families Tupaiidae, the treeshrews, and Ptilocercidae, the pen-tailed treeshrews, and the entire order Scandentia. There are 20 species in 5 genera. Treeshrews have a higher brain to body mass ratio than any mammals, including humans, though this is not uncommon for animals weighing less than a kilogram.

Although called treeshrews, they are not true shrews (although they were previously classified in the Insectivora), and not all species are necessarily arboreal. Among other things, they eat Rafflesia fruit.

Among orders of mammals, treeshrews are closely related to primates, and have been used as an alternative to primates in experimental studies of myopia, psychosocial stress and hepatitis.

So our close relatives like eating bugs, too…

The demoptera or colugos are an interesting group. Flying lemurs:

Colugos ( /kəˈluːɡoʊ/) are arboreal gliding mammals found in South-east Asia. There are just two extant species,[1] which make up the entire family Cynocephalidae ( /ˌsaɪnəsɛˈfɑːlɨdiː/) and order Dermoptera. They are the most capable of all gliding mammals, using flaps of extra skin between their legs to glide from higher to lower locations. They are also known as cobegos or flying lemurs, though they are not true lemurs.

Colugos are fairly large for a tree-dwelling mammal: at about 35 to 40 centimetres (14 to 16 in) in length and 1 to 2 kilograms (2.2 to 4.4 lb) in weight, they are comparable to a medium-sized possum or a very large squirrel. They have moderately long, slender limbs of equal length front and rear, a medium-length tail, and a relatively light build. The head is small, with large, front-focused eyes for excellent binocular vision, and small, rounded ears. When born, a colugo weighs only about 35 g (1.2 oz) and does not reach adult size for 2–3 years.

Their most distinctive feature is the membrane of skin that extends between their limbs and gives them the ability to glide long distances between trees. Of all the gliding mammals, the colugos have the most extensive adaptation to flight. Their gliding membrane, or patagium, is as large as is geometrically possible: it runs from the shoulder blades to the fore-paw, from the tip of the rear-most finger to the tip of the toes, and from the hind legs to the tip of the tail; unlike in other known gliding mammals, even the spaces between the fingers and toes are webbed to increase the total surface area, as in the wings of bats. As a result, colugos were traditionally considered being close to the ancestors of bats, but are now seen by some as the closest living relatives to primates.

So I guess my desire to fly and leap out of airplanes and trees is natural ;-)

Quite an interesting collection of close relatives. Rodents, bunnies, treeshrews, flying lemurs, and primates of various sorts.

So now you know.

Rodents includes not just rats and mice, but squirrels, guinea pigs, and hamsters along with beavers and porcupines. So when someone says we’re being ‘squirrelly’ they might be on to something…

BTW, those rodents can also do hind gut fermentation:

Hindgut fermentation is a digestive process seen in monogastric herbivores, animals with a simple, single-chambered stomach. Cellulose is digested with the aid of symbiotic bacteria. The microbial fermentation occurs in the digestive organs that follow the small intestine, namely the large intestine and cecum. Examples of hindgut fermenters include large odd-toed ungulates such as horses and rhinos, as well as small animals such as rodents and rabbits. In contrast, foregut fermentation is the form of cellulose digestion seen in ruminants such as cattle which have a four-chambered stomach which digests cellulose.

Smaller hindgut fermenters of the order Lagomorpha (rabbits and pikas) absorb the needed levels of nutrients via their upper digestive system by reingestion of cecotropes, which are passed through the intestines and subsequently reingested for added nutrients. Coprophagy is also practiced by some rodents, such as the capybara, guinea pig and related species.

While foregut fermentation is generally considered more efficient, and monogastric animals cannot digest cellulose as efficiently as ruminants, hindgut fermentation allows animals to consume small amounts of low-quality forage all day long and thus survive in conditions where ruminants might not be able to obtain nutrition adequate for their needs. Hindgut fermentors are able to extract more nutrition out of small quantities of feed. The large hind-gut fermenters are bulk feeders: they ingest large quantities of low-nutrient food, which they process for a longer time in a much longer intestine. The main food in that category is grass, and grassland grazers move over long distances to take advantage of the growth phases of grass in different regions.

Hindgut fermenters are subdivided into two groups based on the relative size of various digestive organs in relationship to the rest of the system: colonic fermenters tend to be larger species such as horses, and cecal fermenters are smaller animals such as rabbits and rodents. However, in spite of the terminology, colonic fermentors such as horses make extensive use of the cecum to break down cellulose.

So humans are more closely related to the cecal fermenters than to the colonic fermentors. Which is a good thing as I’d rather not have hooves to deal with or a large gassy belly…

At any rate, now you know…

But just in case someone thinks I’m making up this hindgut fermenter connection:

http://www.indiana.edu/~origins/teach/P380/guts.html

A Tale of Two Caecae…Howler Monkeys & Spider Monkeys

2 sympatric species (Barro Colorado Island, Panama)… both 7-9 kg… most of year they both eat a mix of leaves and fruit, but during food shortages, Howlers depend heavily on leaves (85% of feeding time/day, vs 50% other times of year), while spider monkeys are very frugivorous (typically 83% of time eating fruit, but during transition season, switch to only 60% fruit & more diverse diet)

Gut passage rates: average first appearance of markers…
Howler monkeys = 20 hours… max of 72 hours!
Spider monkeys = 4 1/5 hours… most passed in 8 hours

Milton’s study of ape/human gut passage rates also show humans very fast

Chivers and Hladik plot the proportions of potential fermentation surface area (stomach + caecum + colon) vs absorbtion (small intestine surface area) and find this is a good predictor of whether animals adapted as folivores, frugivores or faunivores…
GUTS:
While some enzymes in saliva begin breaking down carbos, most simple carbohydrate digestion / energy absorbtion takes place in small intestine
Most mechanical breakdown of food into small particles occurs with tools, teeth or in the stomach
Stomach acids can break down some muscle tissues and enzymes break down peptide bonds in proteins (more about this next time). Sacculated stomachs isolate the bacterial fermentation from the normal stomach function
Bile acids and salts (e.g. detergents) help break down lipids in the colon and fatty acids are absorbed through cells lining the colon. The caecum is a chamber attached to the colon where hind-gut fermentation can take place, and is very large in many hind-gut fermenters. Note that the human appendix is essentially a vestige of the primate caecum.

So we’re more optimal for eating fruit than leaves… but can do OK on leaves if we need to; and have adapted lately ( in evolutionary terms) to very rapid absorption of very nutrient rich foods. We are getting a much larger sized small intestine and much smaller amount of large colon.

Due to a colonoscopy when I was not effectively ‘put under’ I can report that I have a much longer colon than most (which is still way less than most other primates) which implies that I’m a more ‘primitive’ sort who can live on less nutritious and more coarse foods. (Though not by a whole lot, I’m still way short of the rest of the primates). This also matches what I know about residency times and some other aspects of digestion. That, and I can maintain my weight with very little total food intake. Trying to lose weight by dieting just doesn’t work for me. (Oddly, an “all you want to eat” while doing little other than sleep resulted in the lowest body weight during my entire adult life – 156 pounds… Normally I’m about 220 lbs or 100 kilos. It seems that if I’m in a ‘nearly hibernating’ environment, I don’t get hungry much and just use what I’ve stored…)

Such are the things you can learn by looking at things like percentage of surface area of digestive organs that are in the small intestine vs large and by looking at close relatives and how they digest food. Yes, I’ve wondered just a little bit if those of us with a touch more Neanderthal Genetics might be a bit closer to our primate paste, able to eat wider ranges of rougher foods, more efficient in digestion, and perhaps with a latent hibernation metabolism that shows during times of starvation… but all that is speculative. As, BTW, have others. There is a thesis that the Neanderthal hibernated to get through the depths of frozen winters. It’s hard to explain how they could get enough calories otherwise. But if they tended to put on a lot of extra weight when times were good, say from a fructose trigger saying to the metabolism “It is spring, start storing fat” as fruit was available; and if they could efficiently digest a wide range of foods, from leaves and fruits to meats and nuts, storing the excess; but easily burning it up when sleeping most of each winter day; well, that would explain a lot…

Things like my being at my heaviest weight when doing full workouts every other day. ( Karate class where the ‘warm up’ included over 100 sit-ups of different sorts… plus all the rest THEN class would start). Tending to gain weight most when eating a balanced diet, but losing it when doing a lot of bed rest and eating a rich high meat diet with dried grains… And why I’m just not a very picky eater. If it’s green, a fruit, nut, or has fins, feathers, or fur; odds are I’ll eat it. But I’ve also eaten frogs, so ‘feathers and fur’ are optional ;-)

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About E.M.Smith

A technical managerial sort interested in things from Stonehenge to computer science. My present "hot buttons' are the mythology of Climate Change and ancient metrology; but things change...
This entry was posted in Human Interest, Science Bits and tagged , , , , . Bookmark the permalink.

9 Responses to Glires and Euarchontoglires

  1. pouncer says:

    Dogs aren’t our relatives; like bunnies. They are, if anything, our evolutionary spouses: each chosen by the other.

    Horses are, I’m sorry to report, our slaves.

    Cats… let’s not go there.

  2. John F. Hultquist says:

    A favorite critter of mine, mentioned in passing in your text, is the Pika. Interesting traits include making mounds of vegetation (aka hay stacks) for winter consumption. Humans also store dried vegetation (think dried fruit) but can’t digest most of what hay contains. Pikas on nunataks in British Columbia are known to eat the brains of birds that have been driven (blown) to the peaks by storms off of the north Pacific Ocean. Humans eat lots of things, including brain. Pikas are also very cute:

  3. Pascvaks says:

    Many thoughts come to mind from your posts, this one had a gigabunch. A few –
    We are what we eat – so true. This thought has come up a few times lately re additives and things like pink slime, we really do have a very advanced digestive system, don’t we? We have evolved quite a body, yet we still find all kinds of crazy, thoughtless ways to abuse it; seems our brain is not as developed as our digestive and other systems;-)
    Thinking about the Old KT Event – pretty lucky for us we were making nice little holes in the ground to sleep and hide in when that happened. Bet if it happens again, some of our little cousins will do alright and things will be pretty cleaned up and back to normal when they get to where we are now. Maybe they’ll be a little smarter than we were. Think we should leave them a pyramid or two full of billions of CD’s telling them all about us, and what the meaning of is is, and where the treasure at the end of the rainbow is really buried? (Guess not, some Arab Prince will probably bust in and destroy everything anyway, what a waste;-(

  4. E.M.Smith says:

    @Pouncer:

    Interesting way to see things.

    Per horses: I think it depends on the horse. Race horses have us pretty well trained to pamper them. Personal riding horses get to spend most of every day with a barn and / or pasture or both. (Few folks ride more than a couple of times a week). The days of draft horses working for a living are largely past, except for the Amish; yet even they stress caring for the animals. Who get a fair share of what they produce, and humans to provide a safe home and protection from predators… also get the property taxes paid ;-) Show ponies get pampered too, though the ones in Hollywood have to work (but hey! They are in the movies! We’re not…)

    I’d rather think us symbiotic organism…

    @John F. Hultquist:

    Always liked the Pika… Odd little fellows, but pretty sturdy, given where they live on frozen mountain tops.

    @Pascvaks:

    What surprised me was how much the human gut had already shortened compared to our ape relatives. We’ve been on a ‘high nutrient fast digestion’ diet for a while now… That, IMHO, means we started eating meat and cooked plants pretty early on. Then again, you get a large response to genetic pressure in 30 generations, that’s about 1000 years for people, and we first left the trees to be “runners of the plains” about 6,000,000 years ago. Some time after that, started eating bone marrow (per the rock chopping mark evidence) from large cat kills (so we’ve been eating bone derived ‘mechanically separated meat’ for a very long time ;-) Maybe hot dogs with it are not all that bizarre and un-natural …)

    When I was on the table for the ‘scope, the doctor commented that he’d had to use nearly the whole thing on me. That would likely make me a ‘couple of sigma’ on the colon length. I sometimes call myself a ‘camel’. If I’ve eaten in the last day or two, I’m OK with not eating today… Some folks I know have to eat 3 meals every day or they go to blood sugar excursions. I just have to average enough calories over about 3 days. I think I’ve got more of the primitive traits…

    I also will eat rough leaves and like it. I’ve made ‘variety greens’ out of many things. Started just as a ‘preparedness’ game. If the broccoli flower is edible, what about the leaves? Turns out that the leaves and even softer stems of almost all cabbages, kales, broccoli, cauliflower, collards, mustards, you name it are all edible. As are the flowers buds of the non-broccoli non-cauliflower ones too. The leaves of ‘green beans’ also make a decent ‘pot herb’ (and are eaten as such in Africa). I don’t mind the string in stringy string beans either (though it drives the spouse nuts ;-) She of the CroMagnon type ;-) Amaranth leaves can be very coarse on some types. Fine with me. Spouse rejects them. Carrot tops are interesting, if a bit chewy. (Don’t eat parsnips tops, they have a skin irritant like poison oak… though I’ve not reacted to it, some folks do. You are supposed to harvest with gloves. I don’t bother.) So it goes…

    FWIW, I’ve thought of writing up a pamphlet of “odd things in your garden you can eat” but figured folks would work it out ‘when the time came’… (Corn silks… not too dry, the wet ones from under the husks… Pea pods even from non-oriental peas – just a bit tough so cook longer and maybe with some bicarb of soda to soften. Pea leaves and tendrils too… ) Mostly, if a plant isn’t poisonous, most parts are edible. (Exceptions exist, so rhubarb leaves, potato leaves, tomato vines all to be avoided – even if the bunny does nibble them… People can have a harder time with the oxalic acid in them, and in clover too. Kidney stones… and a sore mouth…) Acorns can be eaten if the tannic acid is washed out. Flowers of squash plants are delicate and tasty. Many flowers are edible. Fresh sage leaves and flowers are tasty too, if a bit dry and fuzzy. Hmmm… I think I’m starting to drift onto food ;-)

    Per “KT Two”:

    I’ve thought about this a bit.

    Humanity will survive it. Easily.

    MOST people will be killed. But at any given time there are at least tens of thousands, perhaps up to the millions, of people underground. In subways. Skyscraper basements. Military facilities. Storage vaults. All sorts of places. ( I used to work in a records basement sometimes…) They will find a world with most of the people wiped out, but with grocery stores filled with canned goods that will not mind being in 200 F hot air for a while as the atmospheric effects cook anything outdoors.

    Figure if even 10% of the canned goods to feed 300,000,000 people survive, that’s enough for about 30,000,000 ‘people weeks’ (assuming one week inventory ‘in process’ at any one time – it’s actually more than that). So if 300,000 survive, that’s 100 ‘person weeks’ per person. Or about 2 years. By then plants ought to be recovering enough to start a decent biosphere again. There will also be some folks in seed vaults surviving to start planting programs again. Heck, even my ‘jars in the freezer’ ought to survive a couple of hours of 200 – 400 F sky glow (being under a metal awning in a freezer). Then they ‘keep’ for at least 2 years just in closed jars in a metal box in the shade. Anyone who finds them (assuming I get cooked) has a bonanza beyond belief. About a week of food from the large jars of bulk beans and grains, and enough ‘fast seeds’ to get mustard greens and radishes inside 3 weeks.

    Then there are the “preppers”… Many of them are even more prepared with full on bunkers underground.

    So unlike prior events, and even if it DID wipe out most life ‘outdoors’, people will survive as a species. Even massive fires and a ‘hydrogen sulphide’ event would likely not be too bad. With millions of CBW suits / gear in storage, folks would have more than enough for a small survivor population, even if they had to live in them 24 x 7 x 365 for a while. (Though I don’t expect that. While there were some H2S indications, lots of air breathers clearly did not go extinct…

    So about that CD’s and Pyramids: Maybe just make sure the basement storage areas of libraries are fire proof…

  5. Eric Simpson says:

    Ok, coming over now from wuwt, I was reading about half of this, and was pretty entertained. Good writing, also with humor! But time is running short, and I have to put it aside in the bookmarks, yet I want to get the key question answered: how many millions of years do we have to go back to find the spot when bunnies and men shared a common ancestor? I hope I don’t sound like a creationist, but was it, I’m guessing, 35 million years? If you don’t know for sure, what’s your guess? I’ll check back periodically. Thanks.

  6. E.M.Smith says:

    @Eric Simpson:

    If you read down a bit more, the answer is indirectly there:

    http://en.wikipedia.org/wiki/Glires

    This clade joins the rodents and the bunnies. We join them just one more step up.
    […]
    So what is one step up? I mention glires as the next step up is Euarchontoglires or glires with a modifier in front…

    http://en.wikipedia.org/wiki/Euarchontoglires

    Euarchontoglires (synonymous with Supraprimates) is a clade of mammals, the living members of which are rodents, lagomorphs, treeshrews, colugos and primates (including humans).
    […]
    Euarchontoglires probably split from the Laurasiatheria sister group about 85 to 95 million years ago during the Cretaceous, developing in the Laurasian island group which would later become Europe. This hypothesis is supported by fossil as well as molecular evidence. The clade of Euarchontoglires and Laurasiatheria is recognized as Boreoeutheria.[

    So this family formed about 90 million years ago. Then later the Glires split off from primates about 80 million years ago.

    Now if you look at when Primates split off from the ‘not a rodent not a primate’ relatives:

    http://en.wikipedia.org/wiki/Primatomorpha

    Some interpretations of the molecular data link Primates and Dermoptera in a clade (mirorder) known as Primatomorpha, which is the sister of Scandentia. Primates probably split from the Dermoptera sister group 79.6 million years ago during the Cretaceous.

    It’s about 80 million years.

    That puts the splitting of the rodents/lagomorphs from the primates/treeshrews/colugos during that 10 million year span from 90 to 80 million years ago.

    If you want it more precise that that, it is likely to end up in highly technical papers as various academics argue over 82.5 vs 85.2 vs 87.1 vs…

    FWIW, the lemurs (like the ring tail lemur and other ‘wet nose’ primates) split off about 65 million years ago, so at the time of the split from rodents and lagomorphs we were probably rather lemur / tamarin like, a small squirrel sized thing with a tail living in trees and eating bugs and fruit…

    http://en.wikipedia.org/wiki/Haplorrhini

    About 50+ million years later you have Apes of various sorts, and this one ape is starting to think it’s “special” ;-) about 10 million years ago.

    http://en.wikipedia.org/wiki/Ape

    Although the hominoid fossil record is far from complete, and the evidence is often fragmentary, there is enough to give a good outline of the evolutionary history of humans. The time of the split between humans and other living hominoids used to be thought to have occurred 15 to 20 million years ago. Some species occurring within that time period, such as Ramapithecus, used to be considered as hominins, and possible ancestors of humans. Later fossil finds indicated that Ramapithecus was more closely related to the orangutan, and new biochemical evidence indicated that the last common ancestor of humans and other hominins occurred between 5 and 10 million years ago, and probably in the lower end of that range.

    Near as I can tell, the arrival of a real “runner of the plains” as opposed to a tree climber was about 6 million years ago. Same time that grasses evolved. We still had small brains and were under 4 foot tall, but walked upright to see over the grasses and could carry things in our hands.

    My thesis is that humans and grasses are coevolutionary. When the grasses started forming and the forest retreated, some of the Apes were more fond of living on the ground and perhaps even got trapped in shrinking ‘tree islands’, so had to use the grasslands and savanna to increasing degrees. Eventually learning to scavenge large bones for marrow from big animal kills (earliest evidence is that we used rocks to break bones big cats could not break, and scavenged cat kills. Only later learning to hunt for ourselves.) Some pretty long time after that we started using manufactured tools, weapons, and getting larger brains with which to hunt each other…

    The rest, as they say, is history.

    BTW, since a single million years has a lot of change in it (for our line) when folks worry about things like the sun enveloping the earth in a couple of billion years, or even the magnetic field stopping when the uranium driven molten core sets up (in a few million years) as the U runs out: I’m fond of pointing out that that will be a problem for some other species…. as we will have long since evolved on to something else.

    Any worry about how “humans” will deal with things in a few million years simply misses that we are a transitory phase on the way to something else… Always have been…

  7. adolfogiurfa says:

    Monkeys and primates are descendants from humans; humans do not descend from apes. (only some do)

  8. Brian H says:

    About the appendix and tonsils; I believe they’ve now been found to be “protected” repositories for probacteria, forbidden to white blood cells. Hence their dangerousness if they do get infected with bad bugs.

  9. E.M.Smith says:

    @Adofo:

    See:

    https://chiefio.wordpress.com/2012/05/03/dinosaurs-liquid-stone-and-radioactivity/#comment-34948

    Would you be happier if we swapped for “ascended”, as in humans are ascended from chimps?

    It’s the fusion of Chimp 2A and 2B chromosomes into our Chromosome 2 at the telomeres of one end that makes us us.

    @Brian H:

    Tonsils are a lymph node. Their PURPOSE is to get infected. They are the early defense system. Immune system tissue that catches the bug first and starts the machinery of immunity running early. Folks with tonsils out get more pneumonia and related. Their immune system doesn’t get the heads up that bugs are headed for the lungs until it is too late.

    The appendix still makes some vitamins. It does serve also as a reservoir of ‘good bugs’ (as in the original ruminant use). Infection with bad bugs is just bad, wherever you get them. Personally, I need to replenish some of my gut bacteria about once every 3 or 5 years. (Usually after too much antibiotics or after an over the top Tequila Moment ;-) Figured that one out in 2nd or 3rd year of college. Started having “smelly farts” with lots of Hydrogen Sulfide smell, stomache ache, and headaches. Then some constipation. Figure it was due to the liquor having killed off something. Ate a tub of yogurt and placed a bit where “the sun don’t shine” and inside 12 hours was feeling better (that, after a week of no progress). After 24 hours I was fine.

    Tend to avoid too much hard liquor now…

    It’s important to be kind to your bugs ;-)

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