The Biology, Agriculture, and Paleontology thread

There seems to be good evidence that the growth of historical nomadic steppe societies in Mongolia was helped along by a diet of cereals (particularly millet), obtained through trade with neighbouring agrarian societies.

Echoing hymn of my fellow passerine | Art blog (under construction)

Their rise was preceded by a population increase, no doubt.

Undoubtedly, living on the steppes means it doesn't take much population increase for nomadic tribes to start moving outwards.

Optimism is a duty.

The other consideration was the carrying capacity of the pastures they lived on. The Eurasian steppes were ecologically quite resilient on the macro level and could sustain some pretty massive animal herds, but there's only so many animals that a stretch of grassland could sustain at a given time. When you hit that limit, your options would be to:

1. Disband the tribal group and disperse so individual families could survive by looking for new pasturelands,
2. Sell off the surplus animals, or
3. Use your herds (particularly horses) to go to war. Archetypal steppe superpowers like the Mongols really only cropped up once every few centuries; mostly this would mean raids, extortion or seizing the pastures belonging to rival nomadic communities or frontier settlers.

Pastureland ownership is a Serious Business and probably the biggest driver of violence in pastoral communities. And things get even more interesting when agrarian settlers start moving into pasturelands while their nomadic "owners" are grazing their herds elsewhere. You can look at the farmer-herder conflicts in several African countries to get an idea of how bloody these clashes could get, even in modern times.

Echoing hymn of my fellow passerine | Art blog (under construction)

The first cloned Przewalski's wild horse was apparently born last month, paving the way for the use of cloning technology for conservation.

Echoing hymn of my fellow passerine | Art blog (under construction)

Local Fish Defeat the Entire Field of Evolutionary Biology, Again. A placoderm (armoured fish) fossil in Mongolia from 410 mya, originally discovered in 2012, was found to have a cartilaginous internal skeleton and a skull made of bone.

It's previously believed that bony fishes (and all their vertebrate descendants) evolved from a common cartilaginous ancestor as sharks. But this species, named Minjinia turgenensis, clearly seems to have evolved an early bony skeleton around the time that the earliest sharks started to appear. This might potentially suggest that sharks evolved from a bony ancestor, rather than a (purely) cartilaginous one as previously thought.

Echoing hymn of my fellow passerine | Art blog (under construction)

I mean, that'd just involve an extra step in the chondrichthian tree, and the adquisition of bone goes down a node.

Heh, now the ancestral character of osteichthians will be having lungs...

man the placoderms sure like to get every trait on the biological tech tree.

Secret Signature

On that note, I'd like to bring up my favourite fish meme.◊

Echoing hymn of my fellow passerine | Art blog (under construction)

Aren't they the same group of fish where some species had six fins rather than just four?

That's a couple of clades further down, IIRC. By the current classification, placoderms, cartilaginous fish (chondrichthyes) and bony fish (osteoichthyes) all descended from the same common ancestor. The last group further split up into ray-finned and lobe-finned fish, and it's the latter that descended into tetrapodomorphs, or four-limbed vertebrates.

Echoing hymn of my fellow passerine | Art blog (under construction)

So apparently there was this study a while back where entomologists went Starship Troopers on invasive Africanised honeybee hives in Brazil, "treating" them with an insecticide (shot out from a crossbow, no less) in order to help out local populations of the endangered Lear's macaw, whom they competed with for nesting resources.

Echoing hymn of my fellow passerine | Art blog (under construction)

"Africanized Honey Bees", the only insect you hunt with a cross-bow.

Beautifully preserved cave bears emerge from Siberian permafrost: Two finds recently unearthed the frozen remains of an adult cave bear and a cub.

It's only a matter of time before we find frozen humans as well, I imagine.

Optimism is a duty.

Over/under before we get an unfrozen caveman lawyer?

Keep in mind that those findings are the only good thing of losing the permafrost.

New species of burrowing dinosaur found perfectly preserved in 'Cretaceous Pompeii'

"The newly described species is thought to be the most primitive ornithopod dinosaur to date."

"“It was a small, herbivorous, bipedal dinosaur, about 1.2 metres long,”

"The fossils did not retain any traces of feathers but the skeletons were incredibly preserved in three dimensions.'

"“However, certain characteristics of the skeleton suggest that Changmiania could dig burrows, much like rabbits do today. Its neck and forearms are very short but robust, its shoulder blades are characteristic of burrowing vertebrates and the top of its snout is shaped like a shovel."

Fascinating. It's like something will always fill every niche, depending on what's alive at the time.

New species of burrowing dinosaur found perfectly preserved in 'Cretaceous Pompeii'.

Oh, never mind, I literally got that article from the post above this morning.

Edited by Redmess on Sep 21st 2020 at 3:44:43 PM

Optimism is a duty.

Ornithopods thus far seem to have been mostly scaly, if anything, I'd expect some filaments, and volcanic burial may have burned them off.

Also, the base of Ornithopoda keeps being surprising with each analysis made.

Man, harpy eagles are amazing. Those eagles are huge, and they don't hunt rodents, they hunt monkeys. Pretty big ones, too.

Giant eagles that hunt primates. That is getting rather personal.

Optimism is a duty.

Yeah, that's common. We still have a primal fear of large things flying overhead, and dragons, present in most mythologies, are pretty much eagle+snake+fire, things monkeys fear.

Over in the politics thread, we were talking about Trump's (and other people's) belief that exercise shortens life spans because the heart only has a limited amount of beats before it stops.

About those finite heart beats, I do remember reading a scientific article where it mentions that all mammals have about the same number of heart beats before they die, and that there is a correlation between how fast a mammal's heart beats and its lifespan. I think Trump's (and others') belief about exercise depleting your life expectancy might come from there.

So is there any truth to that? Does anyone happen to know what study that was?

Optimism is a duty.

The finite heartbeat thing is crap. You don’t die because you run out of heartbeats or something.

Disgusted, but not surprised

I think the argument is more that mammal hearts wear out after a while, and they wear out faster with a faster heartbeat. I think it was specifically resting heart rate, though.

Optimism is a duty.

Do We Really Only Get a Certain Number of Heartbeats in a Lifetime? Here's What Science Says.

The article links the following studies:

Elevated resting heart rate, physical fitness and all-cause mortality: a 16-year follow-up in the Copenhagen Male Study.

Animal Longevity and Scale.

There does seem to be some truth to it, though it is not quite as simple as "more exercise shortens your life". The specific risk factor for shortened life span seems to be an elevated resting heart rate. So that's not just when you exercise, but even in rest.

Edited by Redmess on Oct 7th 2020 at 2:26:40 PM

Optimism is a duty.