A Tale of Two Skulls: Part 1

The early colonisation of land by animals more complex than insects was lead by a group known as reptilomorphs, early fish-like animals that had developed four simple limbs to enable them to explore this new world. This began 370 million years ago1, and while these animals were initially aquatic, over the following tens of millions of years they evolved to spend increasing amounts of time outside the water, becoming increasingly amphibian-like.

It’s important to understand what kind of world they emerged into—the late Devonian mass extinction was ongoing, devastating sea life and culminating in the Hangenberg event which ended the Devonian2. On land, it was wet, warm, and completely alien—giant fungus trees up to eight metres tall dominated the landscape, with mats of liverwort covering the ground3. Ferns and the earliest trees dotted the land, creating the world’s first forests4.

By the start of the Carboniferous period 360 million years go, the amphibian-like reptilomorphs successfully colonised the land, but over the next fifty million they faced a new challenge. They were still semi-aquatic, and as such needed to lay their eggs in water, which was fine in the wet warmth of the early Carboniferous, but the world began to cool and dry. The trees of this world had evolved lignin in their wood, but no organism had evolved yet that was able to eat it, meaning that when a tree died it was buried, removing carbon from the atmosphere and laying down vast beds of coal5.

However, one group of reptilomorphs evolved to become increasingly lizard-like, and 310 million years ago they evolved the ability to lay eggs on land, without the need to return to the water6. The reptilomorphs were now two distinct groups: the amniotes, with their new-found ability to lay eggs on land, and the amphibians, who are still recognisable today.

The amniotes spread across the world, but there are two groups of particular interest to this story—the synapsids and diapsids. These two groups were named after a curious feature of their skulls, with the synapsids possessing one hole behind the eye7, and the diapsids two8, and these are the skulls that will form the basis of our story.

As the world continued to cool, the rainforests that allowed the ancestors of amniotes to colonise the world began to collapse, creating new niches that amniotes could inhabit but amphibians couldn’t, allowing them to spread and diversify. This marked the dying days of the Carboniferous, and as the ice age rolled in 300 million years ago, the Permian began.

For fifty million years, the Permian was dominated by two groups of large land animals: the amphibians and the synapsids. The diapsids were relegated to small, lizard-like organisms, failing to measure up against the several-metre long amphibians like the Diadectes9, or the pelycosaurs—synapsids that included the apex predator Dimetrodon10.

Dimetrodon NT2 small.jpg
Dimetrodon, an early-Permian syanpsid, by Nobu Tamura

Diadectes1DB.jpg
Diadectes, an early-Permian amphibian, by Dmitry Bogdanov (CC BY-SA 3.0, Link)

Towards the end of the Permian, amphibians, synapsids, and diapsids continued to diversify, including two seemingly-unimportant groups—cynodonts, a diverse group of synapsids that could be readily described as ‘small-dog lizards’11; and the archosauriformes, diapsids that superficially represent ‘crocodile-lizards’12. At this time, nothing seemed capable of ending the dominance of amphibians and synapsids over the land.

Until the Great Dying.

Procynosuchus BW.jpg
P. delaharpeae, an early cynodont, by Nobu Tamura

Archosaurus ross1DB.jpg
Archosaurus, a late-Permian archosauriform, by Dmitry Bogdanov (CC BY-SA 3.0, Link)

Feature Picture: Thrinaxodon, an early-Triassic cynodont, by Nobu Tamura

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A Tale of Two Skulls: Part 1

Billionaires 2017

Forbes recently released their list of billionaires for this year, and the amount of wealth on the list is staggering: $7.67 trillion USD, roughly 10% of global GDP1 and 18% higher than last year.  This data didn’t really tell me much, though, and in order to understand it I investigated three questions:

  1. are the individual billionaires richer, or are there just more billionaires;
  2. has their wealth increased in real terms, or can this be explained away by inflation;
  3. did they become richer because the world became richer, or because of wealth concentrating?

The first question is the easiest to answer, with the numbers on the list: the wealth of the world’s billionaires increased from $6.5 trillion USD in 2016 to $7.67 trillion USD in 2017 — an increase of 18%— while the number of billionaires grew from 1 810 to 2 043 — a total of 13% — meaning a total per-billionaire growth of 4.5%2.

In order to determine whether this growth is real, in that it represents an actual increase in spending power, we must compare the growth to inflation, which is the measure of how much wealth has devalued; a pound sterling in 1700 was worth considerably more than a pound now. Global inflation from 2016-2017 was 3.28%3, which means their wealth grew 1.22% over inflation, indicating a real gain in wealth of 1.2%. From this we can conclude that, on average, the world’s billionaires have gained wealth in real terms.

Does this increase in wealth indicate they own a bigger share of the pie or, as many in favour of trickle-down economics argue, that they’re growing the pie for everyone and just taking their fair share for themselves? According to the International Monetary Fund, IMF, the global economy grew by 3.4% from 2016-20174, meaning that the billionaires’ wealth is increasing faster than the total wealth of the planet by about 1%.

But the story doesn’t end there: because we’re comparing the wealth on a per billionaire basis, we should compare the global economic growth on a per capita basis, meaning we need to take into account global population growth. In the past year, the world population has increased by 1.11%5, meaning that the average person saw 2.3% more wealth, slightly more than half the rate of billionaires.

We’ve now answered our original three questions:

  1. billionaires have gotten wealthier faster than the number of billionaires has grown;
  2. the wealth growth has been real, rather than a product of inflation;
  3. while some of this growth is due to a global increase in wealth, half is attributable to wealth concentrating; the pie is growing twice as fast for the billionaires as it is for everyone else.
Billionaires 2017