Previous Posts about Paleontology: Sep 15, 2022
As regular readers know, I write on many diverse topics in this Substack- from current geopolitics and social trends to paleontology and astronomy. However I keep jumping from topic to topic, based on what is occupying my interest on that day. Consequently many of my posts on a single area or topic get spread over a few months. Hence, it is often hard for readers to quickly find all previous posts on a specific topic/ area. I have decided to, occasionally, put up meta-posts containing a list of links to previous posts about specific topics. This should also make it much easier to search the archives for previous posts on a specific topic or area.
The Thylacine aka Tasmanian Tiger is Probably Still Around in Tasmania
To summarize, it is likely that small isolated populations of the Thylacine are still around in Tasmania. This conclusion is based on number of converging factors such as the number and geographical distribution of sightings, relatively small size and reclusive nature of animal, large amount of almost uninhabited area with enough food and moderate to heavy forest cover for hiding as well as the hilly terrain in interior of Tasmania.
Human Faces and Figures are Curiously Absent from Paleolithic Cave Art
What changed in the human mind after people started using metals and farming the same plots of lands, year after year. And yes, I am aware of some researchers who claim that a few poorly scratched-out reliefs in a few caves represent human faces. But the question still remains- why did cave artists spend so much time and effort drawing wild animals accurately while simultaneously ignoring far easier and more important subjects around them.
Multicellular Life Arose More than Once and is Far Older than We Think
As it turns out, 2.1 billion years ago was immediately after the Huronian ice ages, when atmospheric oxygen levels had finally reached somewhere between 1 and 2% and Eukaryotes had recently gained endosymbiotic mitochondria. It is therefore within the realms of possibility for simple differentiated multicellular animals such as slime molds, proto-fungi, jellyfish-like animals and proto-wormlike creatures to have evolved from unicellular Eukaryotes in the 50-100 million years years after the Huronian glaciation ended.
Antarctica was Much Warmer as Recently as 2.6 Million Years Ago
To quickly summarize, there is evidence that many coastal regions of Antarctica, during the late Pliocene (2.6-2.3 million years ago), were about 30 degrees Celsius warmer than today and resembled parts of Northern Canada, Inland Alaska and Northern Russia . It is also likely that the inland icesheets during that era were significantly thinner and smaller than those present today. Let me remind you that this was during a time when atmospheric CO2 levels were identical or lower than those seen today.
Unanswered Questions about the Cretaceous–Tertiary Extinction
As you can see, our current understanding of the K-T extinction event is rather incomplete. We still don't have a proper understanding of what combination of factors caused it and why it is noticeably bigger than the previous Triasic-Jurrasic extinction. We also do not fully understand why mammals and "modern" birds survived (at least some of them) it, but small bird-like dinosaurs and so-called "archaic" birds did not.
More Unanswered Questions about the Cretaceous–Tertiary Extinction
We also do not understand why certain vertebrates such as "modern" birds aka Neornithes survived, but other sibling groups such as Hesperornithes, Ichthyornithes and Enantiornithes became extinct. This pattern of disappearance is especially odd since groups such as Enantiornithes were significantly more successful than Neornithes prior to the K-T event. Moreover, they were almost identical in general appearance, size range, flight characteristics and likely even patterns of coloration and markings to birds that are still around.
Some Ancient Myths are Based in Historical Fact
However as the last ice age ended and sea levels started to rise, much of this previously prime coastal and almost certainly inhabited land areas ended up underwater. While the overall process was gradual, there were multiple instances of sudden large increases in water levels as well as evidence of serious and prolonged weather disturbances during this transition. You can be very sure that people living in those areas, in many cases for thousands of years, saw these changes (especially the massive changes in weather patterns and occasional instances of rapid water level increases) as divine punishment or retribution.
What do you think? Comments?