When did Warm-bloodedness Evolve?

A correspondent pointed me towards THIS ARTICLE which discusses how to determine whether an animal was warm blooded. And the answer is found in the inner ear!

Being warm blooded confers many advantages. We are more active, both day and night, larger brains become possible.

The inner ear affects balance and it requires liquids to be in the inner ear. Obviously the viscosity of the fluid will have an affect. The viscosity of the fluid will affect the shape of the ear canals; warm bodies will have a different shape of ear canal from cold bodies. 

Warm bodied creatures will have a constant temperature in the inner ear and therefore a constant viscosity of the fluid. Cold blooded creatures will have a varying temperature and viscosity of the inner ear fluid and this will affect the architecture of the inner ear.

The researchers looked at the ear canals of the rich fossil heritage of the South African Karoo. This covers the period in which warm bloodedness evolved.

And the conclusion reached is that warm bloodedness happened 33 million years prior to the origin of mammals. Mammals appeared at 200 million years BP, so endothermy (warm blood) started 233 million years ago.

The brain (pink) and inner ear (green) of a modern mammal, a primate, reconstructed in 3D. Julien Benoit

A Fish Which Stayed in the Water 

A correspondent sent me THIS LINK which describes an early tetrapod (from which we are descended) which could have ventured on land but decided to stay in the water.

The fossil was found on Ellesmere Island in the Canadian Arctic. CT scanning was used to see inside the rock, and to the surprise of the investigators it revealed a fin. They had already determined that they were looking at a tetrapod. Instead of finding fingers and toes they had a fishy fin!

They surmise that the beastie had turned back from the waters edge and evolved to live, once again, in open water. 

This shows that evolution is not a one way street - evolution is a reaction to local pressures.

An animation of the pectoral fin of Qikiqtania showing how it was preserved in the rock. Scales are shown in yellow, fin rays in blue, and the endoskeleton in grey. Credit: Tom Stewart

Down to Earth Extra August 2022 

The June 2022 edition of Down to Earth Extra has been published. You can get it HERE. Or you can read it below.

 

New Old Fossil from Charnwood 

I have just come across THIS ARTICLE on the BBC web site. It tells us of a new fossil found in the Charnwood Forest, near Leicester. It is Auroralumina attenboroughii, named after Sir David. The creature is thought to be a cnidaria - a group which includes corals, jellyfish and sea anemones. And may be the earliest predator found.

It was found as a result of a big cleaning operation of a quarry rock face. Charnwood was where the first Pre-Cambrian fossils were identified in the 1950's. (Fossils had been found in the Ediacaran Hills of Australia earler but the age of the rocks was not known at the time.)

The original article can be found HERE. The BBC article gives a very good and readable introduction to the find.

The fossil surrounded by other Ediacaran species

A New Way to Classify Minerals 

A correspondent has sent me the link to THIS ARTICLE. It writes about the classification of minerals. The classification of minerals I learnt in the 1960's was based on the minerals structure, the method introduced in this article is based on how the mineral formed.

A common mineral such as pyritr has one structure but can form in twenty one different ways. The new classification considers how the mineral formed as being as important as its structure. Apparently there are fifty seven processes that can form minerals. Perhaps a text book will appear that treats minerals on the basis of their formative process

The article makes much of the fact that many minerals are formed as a result of life but this is not news to mineralogists! Learning about mineralogy on the basis of structure does not mean that one cannot appreciate how a particular mineral formed.

The bible of my mineralogy education.

(As an aside, my copy in 1965 cost me 45 shillings - £2.25. The current edition costs £67.53)

Tour de France - THE GEOLOGY!!! 

I wish I had come across THIS SITE a couple of weeks ago. If, like me, you find the Tour de France hypnotic, but occasionally get distracted by the glimpses of the geology and wonder what that is, then this is the site for you!

It describes, in a very simple way, the geology the race passes through. So you get an introduction to French geology with lots of nice diagrams and short essays about the interesting details.

There is an annoying map of the geology alongside the text - it is too small and the pop up rock descriptions are bigger than the windolet. Much better to go to the source of the geological map - Macrostat. Last week I mentioned the BGS Map Viewer; this site does a similar job for the whole world. Well worth looking at!

New BGS Geology Viewer 

The geological survey has released a NEW VERSION OF ITS GEOLOGY VIEWER. There is an introduction to it HERE

It seems pretty good. The screen grabs below show how it looks. There is a legend at the left side but is not very useful. To find the rock type you are best to click on the map and the rock name, age and very short description pops up. Click on "More Information" and the BGS Lexicon appears giving you all you could possibly want to know - probably.

A New Landscape and Geological Guide to Our Area 

Dave Green, well known to geologists throughout the West of England, has produced a guide book which came into my hands today. It is entitled "The Quantocks and North Somerset Coast". It is published by The Crowood Press. The Book Number is ISBN 978 0 7198 4043 2. You can, no doubt, get it from all good bookshops for £20.10. It is also available from Amazon. Bookshop.org has it for £15.79.

I will write some more about the book shortly.