Getting naked
In her article “Not even a theory to cover our nakedness”, Elaine Morgan explores possible reasons why humans lost their thick body hair (19 September, p 28). Surely the simple answer is because we could.
Hair is biologically expensive. It requires valuable protein and energy to make, a lot of maintenance, and can harbour parasites. While the insulation it provides may repay these energy costs by keeping the animal warm when its surroundings are cold, it limits the amount of strenuous activity possible for finding food when the animal is hot.
Uniquely among animals, we have the intelligence to produce workable substitutes for body hair, such as clothes, houses and fire. No other animal even comes close to such a convenient insulation strategy.
It seems to me that Homo sapiens became hairless to save time. All hairy and feathered species spend large chunks of the day grooming themselves or each other. Primate society in particular revolves around grooming, which is vital in maintaining the health of their body cover.
Early Homo sapiens had an entirely different kind of life to other primates. With hunting, gathering and questioning there would have been neither the time nor the numbers in the social group for satisfactory grooming. Consequently, health could be compromised.
Selection pressure would therefore work in favour of hairlessness, and with it a substitute for hair’s protective powers: subcutaneous fat and sweat glands to suit the new lifestyle. Fortune favoured the bald.
Peregian Beach, Queensland, Australia
While reading Morgan’s essay, I was surprised to find that you did not make more of the fact that Alister Hardy chose New 杏吧原创 to publish his article “Was man more aquatic in the past?” (17 March 1960, p 642). Instead, it made reference only to an “aquatic idea”; not a theory, nor even a hypothesis.
Let’s face it, the aquatic theory is the only game in town. No other theory even begins to explain the oddities of human evolution. I have never heard a plausible argument in favour of the savannah theory, yet I am still frequently confronted with it.
When is the aquatic ape theory going to be given the acceptance it deserves? Morgan deserves a Nobel prize for her perseverance in the face of derision 鈥� which is all the opponents can do 鈥� as well as for her work in this field.
Alva, Clackmannanshire, UK
Space enough?
Your feature on population growth and sustainability missed two important issues: the possibility of space colonisation and the likelihood that a medical breakthrough in human ageing could lead to another surge of growth through extended lifespans (26 September, p 34). These are, in fact, closely linked, as the medical problems of life in space are similar to those of old age.
Space colonisation would be far more likely if private companies were to break the global space agency monopoly on crewed space flight. Equally, it will only happen with continued high consumption of the Earth’s natural resources.
If space colonisation becomes possible, then the carrying capacity of the solar system for human and post-human life is clearly many orders of magnitude greater than that of Earth alone, putting the future development of our species into a somewhat different perspective.
In the “Big thinkers, big ideas” section of your “Blueprint for a better world”, I was astonished to read J. Richard Gott lending his name to the notion of colonising Mars (12 September, p 35) when there are other arid and inhospitable areas that could be made habitable more cheaply and safely: the Earth’s deserts.
Our long-term survival prospects would be more effectively improved by spending money repairing the damage that we have inflicted on the Earth rather than exporting our foolishness to other planets.
Binalong Bay, Tasmania, Australia
Temeing
Susan Blackmore’s article (1 August, p 36) describes “temes”, as the third replicator, the first being genes, the basis of biological evolution, and the second memes, the basis of cultural evolution.
Following Blackmore’s own logic in The Meme Machine, digital information is in fact a natural extension of meme-driven evolution. She postulates a difference between memes and temes, based on the fact that the latter are digitally stored and processed. However, she neglects the fact that the ultimate requisite for a replicator is self-sustained selection. Nonetheless, the battle between different temes still occurs in our primate brains, not in the digital realm. As long as this is the battleground, temes shall remain memes.
Borrowing on Blackmore’s example, the evolution of Google’s processing systems is clearly meme-driven, not teme-driven. Google’s filtering algorithms do not evolve in response to the data they process, but in response to their success at persuading our brains that they are getting us the memes our parasitic memeplexes tell us we wanted to get.
There is a third type of replicator that has also been around for more than 30 years: the computer algorithm and, more to the point, the computer virus. Viruses and most algorithms evolve typically only by human reprogramming, making them memes. However some have been programmed to evolve on their own. As such, they are free of the human brain and they can, to some extent, modify their breeding grounds. Their persistent failure to spread over the world and subjugate us under a digital dictatorship speaks volumes about the lack of flexibility in serial computer systems and programming languages. But, as Blackmore predicts, we will eventually get there… or maybe they will.
Blackmore is decades too late in calling for names for the third replicator. Eric Drexler asked the very same question in his 1986 book, Engines of Creation, and the answer is nanobots.
The question now is: what do you call the fourth replicator? If this fourth replicator is to be characterised as an information entity replicating, or self-replicating, in cyberspace, then I would suggest calling it a cyberbot or an ibot.
Canberra, ACT, Australia
Fewer people
It is sadly the case that, while Martin Rees’s belief that population control can be achieved without draconian measures may be correct (“Big thinkers, big ideas”, 19 September, p 33), it will not be possible to do so in time to produce a sustainable planet.
As was shown in the early part of the 20th century, the rate of population increase diminishes quickly with large rises in the standard of living. However, such increases in living standards for the developing world will require more energy than renewableand nuclear power can supply in the near term. The only viable source will be fossil fuels, leading to severe climate change and energy shortages.
Is there then any alternative to draconian measures, apart from famine and pestilence?
From William Hughes-Games
In “Learn to love genetic engineering”, Michael Le Page makes the case for getting over our fear of modifying our food crops (12 September, p 37). Forget about eating built-in pesticides and big companies monopolising the seed supply 鈥� the major reason to fear genetic engineering is that it will probably work, and further increase our food supply.
The last green revolution increased the yields of the most important grains by a factor of two or three and the Malthus-Parkinson law took effect: population increases to use up any available food resources.
Waipara, Canterbury, New Zealand
Human versus forest
William Laurance’s article “Roads to ruin” verged on being inhumane (29 August, p 24).
In many cases, the people exploiting the rainforest work in appalling conditions 鈥� heat, humidity, tropical disease, unsafe work practices 鈥� because they want to create a better life for their children. They use their high-risk, above-average incomes to buy for their children all the things they never had 鈥� education, medical care and good food.
If the price of such people lifting themselves out of grinding, hopeless poverty is the destruction of every rainforest on Earth, so be it. We should not stand in their way, unless we can offer them a realistic way of improving their lives.
The forests of Brazil, Indonesia and Congo belong to the inhabitants of those countries, not to us.
Battery power
Andrew Fogg’s concerns about the practicalities of refuelling electric vehicles are built on flawed assumptions (12 September, p 27). Electric vehicles use a different refuelling paradigm from hydrocarbon-fuelled vehicles.
The average annual distance driven by a private car in the UK in 2007 was 14,274 kilometres, or 39 km a day. A car which will drive for 160 km without refuelling, and can then be charged up from a domestic power supply overnight, is perfectly satisfactory for the vast majority of journeys. For journeys where drivers wish to drive further than the normal fuel range of their vehicle, recharging stations could be used, perhaps by swapping batteries.
Based on Fogg’s pessimistic equation of a 60-litre tankful of diesel to 200 kilowatt-hours, which would typically power a standard car for over 700 kilometres, a 10-hour overnight charge would require a far more manageable 20 kilowatts. Enough energy for a daily 150-kilometre journey could be fed in overnight using a small fraction of that power.
Flight of fancy
I was surprised to read that the stars do not contain enough lithium-7 to be consistent with theories of the early universe (5 September, p 34). Surely we should not be looking for this inside stars. It will be found one day deep in asteroids, planetoids and exoplanets in the form of dilithium crystals, which we will mine to power our warp drives.
For the record
鈥� In our article on robotic insect flight, we misspelled the name of Daedalus Flight Systems (26 September, p 22).