martes, 23 de octubre de 2012

La Cueva Negra (Black Cave)

Vídeo añadido a Paleo Vídeos > Prehistoria de España y Portugal > L.R.1.6 nº 22.

"La Cueva Negra" es una película documental de animación digital producida por la Fundación Integra, que transporta al espectador a la Región de Murcia hace casi un millón de años, en concreto, al Estrecho del río Quípar, una zona de Caravaca donde se ubica el yacimiento paleontológico de La Cueva Negra, cuyos descubrimientos han servido de base científica para el desarrollo de esta obra audiovisual.

Entrada relacionada

Invention of cooking made having a bigger brain an asset for humans

Raw diet makes feeding 86bn neurons a nine-hour-a-day job, which explains evolutionary tradeoff in gorillas, scientists find

If human beings had not invented cooking as a way of increasing the number of calories they consumed, they could only have supported the 86bn neurons in their big brains by spending an impossible nine hours or more each day eating raw food, according to a scientific paper published on Monday.

The research, the authors suggest, explains why great apes such as gorillas, which can have bodies three times the size of humans, have considerably smaller brains. Though gorillas typically spend up to eight hours feeding, their diet influenced an evolutionary tradeoff between body and brain size; supporting both big bodies and big brains would be impossible on a raw food diet.

The brain is so energy-hungry that in humans it represents 20% of the resting metabolic rate, even though it only represents 2% of body mass, suggest Professor Suzana Herculano-Houzel and Karina Fonseca-Azevedo of the Institute of Biomedical Sciences at the Federal University of Rio de Janeiro.

"Why are the largest primates not those endowed with the largest brains as well? Rather than evidence that humans are an exception among primates, we consider this disparity to be a clue that, in primate evolution, developing a very large body and a very large brain have been mutually excluding strategies, probably because of metabolic reasons." [...]

Reference: Karina Fonseca-Azevedo andSuzana Herculano-Houzel.
Metabolic constraint imposes tradeoff between body size and number of brain neurons in human evolution .
PNAS 2012 ; published ahead of print October 22, 2012, doi:10.1073/pnas.1206390109

Fuller picture of human expansion from Africa

A new, comprehensive review of humans' anthropological and genetic records gives the most up-to-date story of the "Out of Africa" expansion that occurred about 45,000 to 60,000 years ago.

This expansion, detailed by three Stanford geneticists, had a dramatic effect on human genetic diversity, which persists in present-day populations. As a small group of modern humans migrated out of Africa into Eurasia and the Americas, their genetic diversity was substantially reduced.

In studying these migrations, genomic projects haven't fully taken into account the rich archaeological and anthropological data available, and vice versa. This review integrates both sides of the story and provides a foundation that could lead to better understanding of ancient humans and, possibly, genomic and medical advances.

"People are doing amazing genome sequencing, but they don't always understand human demographic history" that can help inform an investigation, said review co-author Brenna Henn, a postdoctoral fellow in genetics at the Stanford School of Medicine who has a PhD in anthropology from Stanford. "We wanted to write this as a primer on pre-human history for people who are not anthropologists." [...] ScienceDaily

Journal Reference:
B. M. Henn, L. L. Cavalli-Sforza, M. W. Feldman. The great human expansion. Proceedings of the National Academy of Sciences, 2012; DOI: 10.1073/pnas.1212380109

Actualización 28-10-12. Un nuevo análisis de la Universidad de Stanford ofrece un panorama más completo de la expansión humana fuera de África