Going back in time

Brain Development

For the growth of brain cells, a one-to-one balance of two groups of fatty acids is needed – called omega-3 and omega-6 fatty acids. This balanced combination promotes the growth of the cerebral cortex, the site of intellect and reasoning in the brain.

It is argued by some that the greater intakes of these long chain fatty acids, found in fish and wild game, were a major reason for humankind’s extraordinary increase in brainpower. However this ignores three important facts.

Firstly, parent sources of the omega-3 and omega-6 fats are found abundantly in plant foods.

Secondly, the main source of the omega-3 fats in, for instance, fish, is not the fish itself but the food the fish feeds on – green plants such as microalgae. Microalgae contain omega-3 fats called EPA and DHA, whilst seaweed is a source of DHA.

Thirdly, gathering green plants for their fats instead of fish would have been both far easier for our early ancestors and a much more guaranteed and regular source of these fats – plants tend not to run (or swim) away! On the coast, the diet would inevitably have included seaweeds and microalgae. For further information on fatty acids see the Viva! Health’s guide, Fish-free for Life. It is the same argument that can be used against meat being the dominant force in the evolution of our bigger brains – meat could never have been a guaranteed, continued source of nourishment due to the problems of securing it.

Killing wild animals is far from easy, and if early humans had relied on meat alone they would have gone without most of the time. The bulk of the diet was what it always had been, gathered from wild plants and some of it, no doubt, dried and stored.

Sixty million years ago the lower primates first developed – the mammals from which we all sprang. So much of what makes us skilled as mammals was developed at this time. The change from clawed paw to a hand that grips was invaluable for picking objects up and for using sticks and stones as tools. Our vision became stereoscopic as the eyes moved from the side of the face to the front. These overlapping visual fields produced the ability to see in depth – vital to identify predators from a distance.

A species – in order to survive and rise in dominance – must be flexible, must adapt to changing conditions and take advantage of the unexpected. All living creatures that depend upon a particular environment for their survival are doomed to extinction if that environment is destroyed. The key to success is not only flexibility but also inconsistency, the art of confusing your predators. Lemurs, one of our earliest primate ancestors, stayed in the trees for most of their time and their diet was limited to leaves, nuts, fruits, berries and edible stems. Their habitat has remained more or less similar for 60 million years.

Twenty million years after the lemurs came the anthropoids, the higher primates that now include monkeys, apes and humans – another group of vegetarians. Between five and 25 million years ago this group was diversifying and colonising Africa, Eurasia and the tropical Americas using the land bridges that existed at that time.

They would have moved great distances, from cool to warm, from cold to hot and it is thought that the cooler northern climes helped to develop the anthropoids and led them to eat more bark, the cambium beneath the bark (which is high in protein and carbohydrates) and the leaves of evergreens. They were all vegetarians but the diet was widening with many more food choices – and a richer diversity of nutrition means greater intelligence.

Around 18 million years ago came the hominoids, apes which lack tails and have larger brains and bodies than the monkeys. They evolved in Africa and included one called Proconsul, sometimes referred to as the ‘Daddy of us all’. It is thought that we share this ancestor with the gorilla and it, of course, is another famous vegetarian. DNA studies show that we have a close relationship with the gorilla and the chimpanzee and that we split from one common ancestor around five to six million years ago.

Because we have the fossilised jaws to study, we know that these primates were herbivores and ate fruits, nuts, berries and the cambium which grows in the spring beneath the bark as the tree begins to swell. Some of us still eat it today and we call it slippery elm, a popular health food supplement for digestive disorders.

Three-and-a-half million years ago, Australopithecus afarensis, nicknamed Lucy, appeared. She was small, strode over the African veldt and through the forest, lived near 10 whe at-e aters or me at-e aters ? going back in time 11 A GUIDE BY V I VA! water and was also a herbivore. There were many different types of Australopithecines and one was called Robustos. He has been labelled a war-like killer and the source of our aggression. He was in fact also a vegetarian but he used the bones of large mammals as tools to dig up roots and bulbs. It was the discovery of these bones alongside his own that made anthropologists think they had found the first hunter. They were at least a million years out.

MEAT-EATING BEGINNINGS

So when did meat-eating begin? We can roughly date hunting because of the tools needed to kill but before that there were some very basic tools used to cut, scrape and dig. These were found with the remains of Homo habilis, who lived between 1.4 and 2.3 million years ago. Anthropologists think it is likely that Homo habilis first scavenged his/her meat from the kill of big cats but like so much of what is said on the evolution of humans, this is just speculation.

Hunting started around 1.9 million years ago with the advent of Homo erectus, who lived until 300,000 years ago. Anthropologists tell us this as if Homo erectus, from then on, just ate raw meat and nothing else. In fact, Homo erectus could not have survived on meat alone, as large quantities of animal protein unbuffered by fat or carbohydrates are physiologically harmful (Milton, 1987).

There was even a suggestion that our brain development did not begin until red meat entered our diet. If there was a correlation between the consumption of red meat and the enlargement of brain cells, big cats would have the largest brains and be the dominant species in the world today.