Some almost random thoughts..

Wednesday, September 24, 2008

The Circle of Life.

Darwin's theory of evolution provides an elegant explanation for the diversity of life we see around us. The genes that code for every living organism sometimes encounter a mutation that proves viable and creates a slightly changed living organism. The accumulation of mutations and occasional speciation causes organisms to evolve and diverge in time, and this creates the great complexity and variety of life we see around us.

But gene mutations that change an organism are rare events compared to the lifespan of a single organism. Genes use very effective mechanisms to prevent and correct errors in the copying of the genome (1). Life seems to get on just fine in the time it spends in between mutations. So while the theory of the evolution of life may explain the great diversity of life, it does not explain life itself. The theory of the evolution of life relies on the mutations of the gene. A theory of life should rely only on the gene, because life does not need evolution to stay alive.

Life with sunscreen.

If we put mutations of the genes aside for a moment, organisms move through time business as usual. Humans are born as the children of their parents, live their life, have children of their own and pass away. But if we look at the genes present in humans, they can move from generation to generation completely unchanged. This means that these genes do not live 'in time' in the same way that we do, because they do not change over time. They either exist, or they don't.

The organism that carries the gene brings the gene back exactly to where it was before the organism's life started. So life, from the gene's perspective makes a perfect circle every generation and the gene gets to stay for as long as the organism it codes for manages to reproduce. It is this circle of life that makes the logic of the genes different from what we are used to. A single organism can spend energy in order to gain resources to live and when the net benefit is positive, this is behaviour that can help bring the organism closer towards reproduction. But in the circular gene-centred view, the fortunes of all the organisms it is a part of are interchangeable. A benefit in reproduction to one organism can be covered by a cost to any other organism it codes for. As long as the net result is positive, it makes sense from the gene's point of view.

In practical terms, a gene can code for an organism to take care of its children at great cost, and recover the cost by having the organism taken care of as a child. If the net effect on reproduction is positive, this is a good investment. This means that from the gene's perspective, you do not take care of your children because they carry 'your genes' into the future. You take care of your children because the gene that codes for it, also made your parents take care of you. And this was a good investment of effort, otherwise the gene would not have been able to exist.

The organism that takes care of its children, gets taken care of as a child. If the net effect of this investment in parental care is positive, it can increase right up to the point where the marginal return on extra parental effort reaches zero. For some species this means a couple of seconds, for humans this means almost two decades. Given the helplessness of a newborn child and the relative strength of the parents, the benefits of such an arrangement are obvious.

The cost to an organism carrying the gene can be recovered by a benefit to any other organism carrying the same gene. The essence of interactions of an organism with the outside world is not that the beneficiary is related or not. The essence is that the cost reliably leads to a benefit to an organism carrying the same gene. The benefits and costs can be spread out over multiple organisms and across generations, it is the statistical average profit in terms of reproduction that matters.

It is this reliability in getting a return on the investment that makes interactions with family such an attractive proposition in the animal world. It is fairly easy for the gene to point the organism to the right benefactor, so no effort is lost due to one organism receiving double the help and another getting nothing, this would not add up to the same average benefit in reproduction. Imagine the mother that could not tell its young apart. The effort the mother makes in parental care could end up with just one of its offspring, leaving the mother with one starving young and one overfed. The average reproduction of the three combined would plummet. Luckily, many animals can divide their efforts correctly over their young and parental care is a common investment as a result. Just like taking care of your child means you get taken care of as a child, taking care of your brothers means your brothers will look after you. And that can be a good investment in some species. It certainly is in humans.

Life with genetic mutations.

The gene centred view on life can be used to understand what mutations to the genes are viable. Because life from the genes perspective is circular, we can collapse the effect of the mutation on all organisms the gene codes for and consider only the average effect on the reproduction of the organisms that carry the mutation (2). New adaptations need to lead to an increase in the average reproduction to spread and become the new standard for the species. For genetic mutations that involve interactions within the species, the circular effect must be taken into account. Genetic mutations surround an organism much quicker than they can evolve further so the overriding constraint to a mutations viability is that it can make a profit from living among itself.

The complicated feedback an organism gets from being surrounded by other organisms carrying the same gene, often creates a balancing act within life. Take parental care. Any female with some surplus resources could have started this. And when parental care appeared ('this thing I just dropped is actually quite cute.'), it must have been a profitable investment of effort. Parental care could then increase by further chance mutations right up to the point where the marginal cost balances the benefit. But for parental care among humans to evolve all the way up to the present level of nearly two decades, it will have taken many generations of slow evolution.

So qualitative changes in an organism's building plan can open up long avenues of further quantitative evolution. We may have seen this following the recent appearance of language in humans and its subsequent effect on cooperation and thinking. It opened many new avenues of profitable evolution (in brain power, for example) towards a new balance. Whether it is a viable mutation remains to be seen. Looking at humanity's effect on its environment, it isn't looking all good.


Darwin's theory of evolution showed us how we could have evolved over a very long time from the simplest living organism, via a fish-, reptile- and apelike creature into what we are today. The downside of its success has been that it has made people see all of life as a continuous line from the past into the future.

But without the occasional mutations of the gene, life is better thought of as a perfect circle in the present. Like a blind investor, life puts energy into its surroundings in the quiet faith of a positive return. Family members are important in life not because they are related, but because they are reliable.

1. Sexual reproduction works as a copy control mechanism. It provides several lines of defence against errors propagating in the gene pool. First it lets organisms of the same species swap code in reproduction, keeping both copies. If the gene from one side is defective, it can still use the other. The second line of defence is the specialisation in a reproducing female and a fertilizing male. This limits the chance of encountering the same errors in a gene swap by allowing more distance between the sexes. The third line of defence is sexual competition among the males. The female side that takes care of the actual reproduction gets to choose the least damaged code from among the males. This acts as a circuit breaker preventing broken genes from continuing in the cycle.

2. To become the species standard it needs to make the organism it codes for outperform relative to those with the alternative gene, without making the organism count hit zero. A higher average reproduction will do that, but there are more ways.

From a gene's perspective, there is no such thing as a beneficial mutation. What we see as a beneficial mutation is just one that the gene couldn't stop, as much as it tried. The struggle for life from a single gene's perspective is only about staying the same. Evolution happens because the copying process is imperfect. Evolution is the continued and accelerating destruction of the replicating molecule, those lines that survive need ever more elaborate mechanism to hang on to life.

Hamilton's rule states that a gene can benefit from having the organism it codes for aiding another organism as long as the the cost in terms of reproduction is lower than the benefit adjusted by the degree of genetic relatedness. For genes that are the species standard, all other organism are 100% related and it comes back to the circular gene centred view of life.

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Laughter and storytelling:

All humans are equipped with the ability to experience the same social emotions like shame, pride, envy and respect. But the applicability of these emotions can vary strongly from group to group and over time. So the brain needs us to constantly calibrate our social morals with those of our group. The most efficient way to do this is through storytelling. We evolved a love of listening to stories, because in a stone age setting that would expose us to the reactions of our group to the story. We slowly but surely mirror the reactions we hear around us, like laughter and outrage, so that we end up in sync with the social morals of the group. This shows why watching comedy without the studio laughter is difficult. Not only can't you laugh with others, you actually get the message that what you hear shouldn't be deemed funny, because nobody else is laughing.

Laughter and storytelling combine to make us compatible in behaviour, because when it comes to social morals, it did not pay to be different. In the modern world, we have automated the storyteller in the middle of the group, into the TV-set we mostly watch on our own. But without the vocal reactions of our group, it might have become a waste of time.

Hunting and gathering.

As humans we solved our basic food problem. Getting the calories we need to survive is easy. But like animals in the zoo that get fed, we have kept much of the display behaviour related to our feeding methods throughout our evolution.

The gatherer into gossip and fashion.
The success in gathering partly depends on the quality of your information network. You need to hear in time where the latest fruiting tree is. There may be more than enough for the person that finds it, but not enough for everyone. A gatherer that finds food will share the information with someone that seems likely to be able to return the favour another time. So gatherers have evolved a need to signal having a quality social network and being 'up to date'.

Gossip and keeping up with fashion trends are modern display behaviours linked to the innate need to be up to date and to be seen to be up to date. With gossip, a gatherer has a special interest in being the first in relaying otherwise useful bits of information.

The hunter into sports and career.
Stone-age hunting is a team effort needing diverse skills. You are better off hunting with a few others. But you do not want to bring anyone along who can't pull his own weight. You do not want to share the meat and the glory with a slacker. So the hunter has evolved a constant need to show they will make a valuable team member to other hunters. That is what gets you on the best hunting party and that gets you the best food and possibly 'extra' mating opportunities.

Every opportunity you have to compete with others to show off your skills can help you get picked by the best. Modern sports and even career are behaviours linked to the need to show you are a valuable team member and you deserve your spot in the highest league. The displays needed to establish and keep your deserved rank would settle down in a small group. In our modern large group the hunter has become stuck in this display behaviour because there is always a higher league to get into. And people's social circle has become more homogeneous through the sorting that happens in school, housing and work arrangements. So there is always someone close ahead or behind. This may be an important driver behind the 'never enough' economy.

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