Habitat, genetics and us

As the last Ice Age melts at a fast pace, the upside of that news is that researchers are finding more and more ancient bones, skeletons and artefacts which were previously locked under permafrost. The knowledge accumulating about the kind of habitat extinct life forms experienced has enabled animators to depict paradise-like scenes where amazing creatures roamed before the ice overwhelmed their pleasant pastures. All the science gathered is informing the creative world and together they bring us stunning images to educate and inform us.

Now our human lineage is also clearly identified on an interactive ‘family’ presented here by The Smithsonian at http://humanorigins.si.edu/evidence/human-family-tree

We can begin to understand how the human family have moved on to seek less hostile environments when they felt the necessity and had acquired sufficient confidence with new skills of survival. Once hunted themselves by many fierce creatures, they became hunters and their gathering and storing skills became more sophisticated over time. When arriving in a place of plenty, they settled and became farmers, living in cooperative groups, supporting one another.At some point they began to meet other groups from different branches of the family tree who had developed different genetic patterns. The groups would interbreed and their offspring would acquire some helpful and some not so helpful genes as they evolved.

As the human brain grew through experience and acquiring a diverse range of food sources, the human digestive system also evolved.

Early hominins, living 3 to 3.5 million years ago, got over half their nutrition from grasses, unlike their predecessors, who preferred fruit and insects (forest dwellers whose diet was similar to chimpanzees).

This is the earliest evidence of eating savannah plants, says Julia Lee-Thorp at the University of Oxford. She found high levels of carbon-13 in the bones of Australopithecus bahrelghazali, which lived on savannahs near Lake Chad in Africa.

Just as massive gorillas are vegetarian and whose strength and barrel chest have similarities to Neanderthals, so the vegetarian route to build a diverse gut microbiome evolved.

It is likely that both modern humans and Neandertals descended from Homo heidelbergensis. When Neanderthals and modern humans interbred after thousands of years of separation, the genetic result was that humans around the globe carry the now extinct Neanderthal, genes to between 2 and 3 percent.


Geneticist Professor Tim Spector, in his book The Diet Myth says:

Early hominids like Australopithecus who lived between two and five million years ago were half our size and had much bigger molars than we have. These humans probably didn’t eat much meat apart from insects or reptiles, as they were not fast, agile or bright enough to catch much unless it was already dead. A couple of million years ago during the Ice Age, Africa cooled down and fruit became scarcer. Our Home erectus ancestors, in order to survive, now had to find better hunting and gathering techniques. Studies of chimps show they can take up to eleven hours to chew raw meat properly, so humans wanting better things to do with their time had to work around this. They initially developed stone tools to cut up the tubers, roots and raw meat into smaller pieces.”

It was not until around 100,000 years ago that humans began to light fires to cook their food and thus reduce the time it took to chew before swallowing. They could also dwell in caves, lit by firelight, once too dangerous for them with caves being home to various human predators. Fire warmed their ‘home’, protected them from many dangers, helped them cook and develop hunting tools using heat from the fire to create fixing materials for their tools – fire just enabled more innovation to assist their survival.

As Tim Spector said:

This opened up many more possibilities, as cooked food reduced toxins and the incidence of food poisoning, and allowed much more energy to be extracted from food in a short time.  Importantly, it freed up the valuable time we had previously spent collecting, then eating and digesting the tough roots we’d gathered and the occasional bit of raw meat.

Now that we were eating cooked food, we needed less of the digestive juices and enzymes as well as less fermentation time, so the lower part of our gut shrank accordingly. With the intestines using less energy and receiving more calories from the cooked vegetables and meat, our brains rapidly grew bigger and we became vastly more efficient at hunting meat, a great source of calories.”

In Siberia, there is a location called the Lugovskoe ‘mammoth graveyard’ by scientists Alexander Pavlov and Eugeny Mashchenko. This is a swampy area where thousands of bones of mammals – mainly mammoths – have been unearthed by scientists since the 1990s. It remains unclear to what extent our ancestors ate the woolly mammoth when other, perhaps more succulent, food sources were available. Yet a related discovery last year in Lugovskoe was the remains of a 13,270 year old fireplace belonging to archaic humans in this region. 

The current theory is that mammoth bone was burned with charcoal, the fat from the bone giving a superior heat. Anton Rezvy, 39, head of the palaeontological department of the Khanty-Mansiysk Museum of Nature and Man, explained: ‘The vertebra was found in Lugovskoe mammoth cemetery.’

Other uses for mammoth remains have been discovered. There is evidence of these humans using the giant tusks as support structure and then laying the skins of mammoths in sections over the top to create an enclosed family home. This was recently demonstrated in a documentary series on BBC by Bristol University. Another illustration of astonishing discoveries since caves, such as the one found in Transylvania, have been explored and Siberia is yielding up mammoth finds in once frozen tundra.

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