Tag Archives: Evolution

Simple Human Evolution Timeline

10 MYA  – the climate dried out
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8 MYA  – our lineage split from that of gorillas
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6 MYA  – our lineage split from that of chimpanzees
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4 MYA  – time of the Australopithecines (possibly the first bipedal                                           walkers)
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3.2 MYA – Lucy (the now famous example of Australopithecus afarensis)
was alive in Ethiopia
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3.6 MYA – The Laetoli footprints in Tanzania were created
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2.5 MYA – time of Homo habilis (the first species of the Homo genus and
also thought to have been the inventors of laughter)
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2 MYA – time of Homo ergaster (described as a chronospecies)
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1.8-1.5 MYA – time of Homo erectus (probably the first species in the
human timeline to leave Africa)
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600,000 YA – time of Homo heidelbergensis (this species underwent rapid growth in brain size and is thought to have developed music as a bonding activity)
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400,000 YA – the use of fire took off
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230,000 YA – time in which Neanderthals were also living in Europe
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200,000 YA – time of Homo sapiens (our own species, in which doctrinal religion and complex language were created)
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170,000 YA  – time of the direct ancestor of all humans alive
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10,000 YA  – the use of agriculture began
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5,000 YA  – writing began to be used

skulls imgae

Cooking Complications

We all know how important cooking is to us today. This importance can be better understood through studies of our evolutionary history. When looking at cooking from an evolutionary perspective, we can see how it has not only transformed our lifestyles, but also played a part in shaping our own evolution.
It is likely that food processing began with beating, mashing or cutting food to increase its digestibility. Estimates of when cooking actually began to be used vary hugely. There is some evidence of the use of fire one million years ago, in the time of the H. erectus, however, this is sparce and it seems unlikely that it could have been controlled well enough for regular cooking. There is debate about this however, and there does appear to be evidence for controlled fire use at a one million year old site in South Africa, and at a 800,000 year old site in Israel. There seems to be a large increase in the evidence of fire found at sites across Europe and the Middle East from around 400,000 years ago. Fireplaces and burnt bones begin to be found from this period onwards, suggesting that this is about the time when cooking was mastered.

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The benefits of cooking to our ancestors were enormous. Cooking food greatly increased the energy obtained from both vegetables and meat by making them easier to digest. As well as increasing their calorie intake, cooking also reduced the cost to their immune system, as many more microorganisms in the food would haven been killed. It has been suggested that these benefits of cooking may have played a large role in the evolution of our unusually large brains, which consume around 20% of our body’s energy. When times were hard, fuelling this extremely costly organ would have been nearly impossible. With the invention of cooking, individuals would have been able to consume a greater number of calories, allowing larger brains to become an advantage rather than a hinderance and therefore to be naturally selected for. This is just one example of how cultural changes can effect our physiology.

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It is therefore clear, when taking an evolutionary perspective on cooking, that it appears to be a great advantage. Nowadays, cooking obviously is still hugely important to our lifestyles, and Daniel Lieberman even suggests that our digestive systems have changed so much as a result, that ‘we are now dependant on cooking to survive’. There are, however, several downsides to cooking that are less well known. For example, cooking can destroy a large amount of the vitamins in our food. This especially applies to B-vitamins, which are relatively unstable. Cooking can destroy a large amount of the vitamins B6 and B12, and when cooking potatoes, 20% of the vitamin B1 is generally lost. Boiling or steaming will also cause minerals to be leached away, typically loosing 30-40% of the minerals from foods (kimura et al. 1990). Cooking can also generate undesirable compounds, which I briefly covered in the article ‘meat eaters’. For example, during smoking, grilling or frying, nitrosamines can be generated from nitrates and secondary amines. Other compounds such as heterocyclic amines can also be produced during cooking. The heating of unsaturated fats to high temperatures, also is known to produce trans fats. These both increase the amount of Low Density Lipoprotein in the blood, and reduce the amount of High Density Lipoprotein. This has a sort of double whammy effect on increasing the amount of cholesterol in the arteries, increasing the risk of heart disease.
It is therefore evident that cooking has played a large role in our evolution and, as we know, is now very important to our way of life. There is a large amount of research being carried out into the effects of cooking foods. This even includes whether reheating some types of carbohydrate can change the proportions of resistant starch and fast release glucose contained. It is interesting to speculate about how foods cooked by modern techniques, such as microwaving, may differ from foods cooked by traditional boiling or roasting. We can see how cooking was once extremely important for our survival, however, now, when almost every meal contains cooked foods, we may be beginning to recognise some of the detrimental consequences of cooking that were never apparent to our ancestors.

Sources Used:
The Story of the Human Body
Human Evolution
LiveScience
PubMed – cooking losses of minerals in foods
European Food Information Council review
Livestrong.com
Trust me I’m a Doctor (BBC)