Brain Fossil

The evolutionary history of the human brain shows primarily a gradually bigger brain relative to body size during the evolutionary path from early primates to hominids and finally to Homo sapiens. Human brain size has been trending upwards since 2 million years ago, with a 3 factor increase. Early australopithecine brains were little larger than chimpanzee brains. The increase has been seen as larger human brain volume as we progressed along the human timeline of evolution, starting from about 600 cm3 in Homo habilis up to 1500 cm3 in Homo Sapiens Neanderthalensis which is the hominid with the biggest brain size. The increase in brain size topped with neanderthals, since then the average brain size has been a shrinking over the past 28,000 years. The male brain has decreased from 1,500 cm3 to 1,350 cm3 while the female brain has shrunk by the same relative proportion. However it is argued that another essential element of brain evolution in humans is rearrangement. Larger brains require more wiring, but more wiring can become inefficient. The brain has therefore become reorganized for efficiency. Furthermore the average body size of nethanderthals was larger which lead to bigger brain size. Read more ...

In the News ...

525-million-year-old fossil defies textbook explanation for brain evolution   Science Alert - November 25, 2022
According to a new study, fossils of a tiny sea creature with a delicately preserved nervous system solve a century-old debate over how the brain evolved in arthropods, the most species-rich group in the animal kingdom. Combining detailed anatomical studies of the fossilized nervous system with analyses of gene expression patterns in living descendants, they conclude that a shared blueprint of brain organization has been maintained from the Cambrian until today.

Skull clue to exodus from Africa   BBC - January 28, 2015
An ancient skull discovered in Israel could shed light on the migration of modern humans out of Africa some 60,000 years ago. This migration led to the colonization of the entire planet by our species, as well as the extinction of other human groups such as the Neanderthals. The skull from Manot Cave dates to 55,000 years ago and may be the closest we've got to finding one of the earliest migrants from Africa.

Medieval Skulls Reveal Long-Term Risk of Brain Injuries   Live Science - January 28, 2015
Skull fractures can lead to an early death, even if the victims initially survived the injuries, according to a new study that looked at skulls from three Danish cemeteries with funeral plots dating from the 12th to the 17th centuries. This is the first time that researchers have used historical skulls to estimate the risk of early death among men who survived skull fractures, experts said. The study showed that these men were 6.2 times more likely to die an early death compared with men living during that time without skull fractures. Today, the risk of dying after getting a traumatic brain injury is about half that, likely because of improvements in modern medicine and social support, according to the researchers.

Cutting edge training developed the human brain 80,000 years ago   PhysOrg - June 21, 2011
Advanced crafting of stone spearheads contributed to the development of new ways of human thinking and behaving. 200 000 years ago, small groups of people wandered across Africa, looking like us anatomically but not thinking the way we do today. Studies of fossils and the rate of mutations in DNA show that the human species to which we all belong - Homo sapiens sapiens - has existed for 200 000 years. But the archaeological research of recent years has shown that, even though the most ancient traces of modern humans are 200 000 years old, the development of modern cognitive behavior is probably much younger. For about 100 000 years, there were people who looked like us, but who acted on the basis of cognitive structures in which we would only partially recognise ourselves and which we do not define today as modern behavior.

2,500-Year-Old Preserved Human Brain Discovered   Live Science - March 26, 2011
A 2,500-year-old human skull uncovered in England was less of a surprise than what was in it: the brain. The discovery of the yellowish, crinkly, shrunken brain prompted questions about how such a fragile organ could have survived so long and how frequently this strange type of preservation occurs. Except for the brain, all of the skull's soft tissue was gone when the skull was pulled from a muddy Iron Age pit where the University of York was planning to expand its Heslington East campus.

54-million-year-old Skull Reveals Early Evolution Of Primate Brains   Science Daily - June 23, 2009
University of Florida vertebrate paleontologist Jonathan Bloch shows the preserved skull of the 54-million-year-old primitive primate, Ignacius graybullianus, and the virtual mold of the brain made from the skull in this June 5, 2009, photo at Florida Museum of Natural History at the University of Florida. The mold, known as an endocast, was made using an ultra-high resolution X-ray CT scanner that took more than 1,200 cross-sectional images of the skull.

Primitive Primate's Brain Built   Live Science - June 23, 2009
Using a 54 million-year-old skull, researchers have constructed the first-ever virtual model of a primitive primate brain. To develop their model, the scientists took 1,200 ultra high resolutionX-rays of a well- preserved 1.5-inch-long skull from a mammal belonging to the ancient primate group Plesiadapiforms. The two dimensional X-rays were then stacked up and "stitched" together to form a 3-D model, Bloch said. While this imaging technique has been used to examine primate brains from more recent fossils, no one has used it to study so-called "stem primates," mammals that existed 65 million to 55 million years ago and gave rise to today's primates, until now. The skull used for this model is a "late-occurring" stem primate, a member of a group that survived from the Paleocene (65 million to 55 million years ago) into the early Eocene (55 million to 33 million years ago), Bloch said, adding: "But likely [it] is very similar to what stem-primates would have looked like during the Paleocene."

Oldest fossil brain found in Kansas   PhysOrg - March 2, 2009
The new research looked at four 3-dimensional braincases of iniopterygians found in shales from Kansas and Oklahoma. The specimens share several features with living ratfishes, which means that these skull features have been conserved in the group for the last 300 million years. Complete reconstructions of these skulls were made with a CAT scan and X-ray synchrotron microtomography, and the imaging of one skull showed a dense, symmetrical object sitting within the large braincase. This was the mineralized brain.