How we change what others think, feel, believe and do

Rules of Evolution

Explanations > Evolution > Rules of Evolution

Reproduction | Variation | Selection | So what?

Evolution is the process whereby creatures compete, adapt and survive in the changing environment, by changing themselves. Here is a simple set of rules that describe how we evolve.

Reproduction

A key aspect of life is that we create more life through reproduction. Without enough children to propagate generations, a species will die out.

Finding a mate

The first and most important step on the road to reproduction is finding a mate, including fighting off rivals and wooing the potential partner. Rituals and fine plumage can be seen across the animal kingdom and even flowers use bright colors to attract insects which will help them pollinate.

Inheritance

We inherit genes and hence characteristics from our parents, creating species stability. In particular if both mother and father have the same characteristic, whether it is blue eyes or greater height, then the offspring are more likely to follow suit, although throwbacks to previous generations is possible, as is genetic mutation.

Quantity

The more a life-form reproduces, the more children it has, the greater the chance of some of them surviving to be able to reproduce themselves, which is a critical requirement for species survival.

Some creatures use this quantity principle, for example by laying huge numbers of eggs. Others manage on far less offspring. Creating many children is an adaptive mechanism for prey, where many will be eaten or otherwise not survive harsh conditions. Robust predators, on the other hand, can continue the species with few children.

Quantity is also related to resource availability. More children take more work to feed and protect, and will only survive if there is enough food and shelter for them.

Fertility

Many creatures are fertile or 'in heat' only at certain times in a cycle. For many, this is driven by the time of year when food and warmth will be available. Fertility also relates to the ease with which a mother can be fertilized.

The question of fertility applies to both mother and father. The more fertile the parents and the longer they are fertile, the more children can be produced.

Maturation

There is also the question of how long it takes for children to be reared to adult maturity, where they can start producing their own children. This varies across species from hours to years.

If children take a long time to mature, then a species must be able to ensure survival of the children not only long enough to have their own children but also long enough again so that the children reach maturity and can themselves reproduce.

Variation

A critical element of reproduction is that there is variation from one generation to the next. No individual is genetically identical to a parent.

Variation is good for helping cope with changing conditions. It can also be bad when effective characteristics are lost. Variation hence needs to balance with stability.

Inheritance

We inherit genes from both of our parents. The very fact that we need two parents is common for most of the life forms on Earth and creates significant variation as we take some things from our mother and some from our father.

If creatures are not able to reproduce, either because they die early or because they cannot find a mate, then they will not pass on their ineffective characteristics to their children.

Fidelity

Another force for variation is the extent to which individual and species are monogamous, polygamous or are just disloyal, taking one or more mates.

Monogamy is good for ensuring males stay around to help the female and their offspring survive.

Polygamy allows those who are better at attracting mates and fending off mate competition to spread their seed further. In polygamous species, the male is often larger in order to fight off competition. Female polygamy does happen, but is far less common.

Others either do not have any long-term relationship with a mate or stray outside of the relationship, opportunistically reproducing where they can. Humans are largely monogamous but, as many discover, can also be disloyal.

Mutation

Mutation of genes occurs naturally to create a wide range of possible physiological and neurological changes, from extra limbs to varying mental abilities. This is a critical mechanism that works outside the constraints of inheritance to potentially create whole new species.

It would take a long time for evolution to work if it worked like science, with one carefully controlled experiment at a time. Instead, it uses massive parallelism, with each living thing, with its individual mutations, being an experiment. In this way, many unsuccessful experiments die out (or just don't have surviving children) while the many more successful experiments get to propagate their progeny.

Environmental variation

As well as individual changes there are changes in the environment in which they live. This can include changes in weather, vegetation, geography and other species. A key reason for evolution is to be able to cope with these external changes.

Prey and predators are significant as they form a direct part of the food chain that affects a creature's existence. We live within a hugely entangled, complex species

Selection

Predators and disease

We are all predators of some kind, as life feeds on other life, even if it is just vegetables and fruit. Even bacteria and viruses may be seen as predators who live and reproduce by feeding on more developed forms of life. Although it is less common, there may also be predators within one's own species.

A critical factor for survival of prey is the ability to outwit and escape predators, and evolution has produced some incredible variations which do just that, from camouflage to spikes to off-putting smells.

Competition for limited resources

Another key force in evolution is that there are limited resources for which there may be fierce competition. First of all, this is about food, water and other sustenance. When the food supply runs down or the population increases too far, then only those who can garner enough supplies to live will survive. Space also becomes important, particularly when you dominate an area in which your food lives. This allows creatures to feed their children and so allow the species (or, more accurately, their genetic variant) to survive.

For example plants grow longer roots to reach the water and grow taller to reach the sun, spreading their leaves over less evolved competitors. Animals may grow larger and stronger, although smaller creatures handle limited supplies simply by needing less. A species can overwhelm others just by weight of numbers, such as when locusts rapidly consume all of the food needed by others.

Competition for mates

To reproduce, you need a mate, not just sustenance. This means you must attract or woo her or him, for example with the brilliant plumage and elaborate rituals of birds.

The other problem to handle is competition from others in attracting mates who are most likely to ensure the birth and survival of your progeny. Hence (and particularly in polygamous species) many males are large, strong and fierce, in order to fight off other males, both in attraction and defence of their female partners.

Coping with environmental change

Selection is also done in an overall sense through the ability of the individual to cope with their environment, including the changes that occur here. When it becomes hotter or colder, wetter or drier and so on, the species that survive are those that are either more suited to the new environment or are able to adapt to it quickly enough.

New environments shake things up, even if a species does survive. An animal that thrived in the great plains may become much less dominant when the plains shrink.

It is a mark of the success of homo sapiens that we have adapted to more climatic and geographic environments than any other species.

Hierarchy and roles

When animals live in groups they often form hierarchies and defined roles, such as for foraging and child-care, in which natural selection will have a hand. For example if the carer is too uncaring or if there are not enough foragers, then survival will be threatened.

In tribal societies, status is very important and there are clear pecking orders, with rules for what each level can and cannot do as well as rules for how individuals reach each level. Selection is interesting here, as those at lower levels may get to the remains of the food last, whilst those in higher status positions are often under threat from attack by 'social climbers' all around them.

Collaboration and learning

The extent to which a species can learn and share knowledge will also affect its ability to survive. There is a classic story of how blue-tit birds learned to pierce 20th century aluminium foil milk-bottle caps in the UK in order to drink the cream beneath. One bird discovered this, then as they are a social species, blue-tits were soon doing this all across the country. Robins, on the other hand, did not learn this as they are solitary birds and even if some discovered this, the practice did not spread to other robins.

So what?

Evolution still happens and we are all subject to its rules. Even though we have been 'civilized' for many years, by the timescale of evolution we are not long out of the jungle and the internal drivers for survival still affect us.

Natural selection can be seen in the way individuals find mates and how people rise up within social and organizational hierarchies. Business change is similar to environmental change and those who adapt best are those who survive and rise up the hierarchy.

Whenever you are looking at changing minds, consider the processes of evolution with questions such as:

• What partners do you need? How can you woo them?
• Is it better to be loyal or get a wider experience?
• Who are your competitors? How are they learning and evolving?
• What form does hierarchy and status take? How might this change?
• What variation may happen? How can you use this principle?
• How can you spread your ideas? How do ideas thrive or get killed off?
• What changes in the environment are happening? Who will survive them? How?

The principle of massive parallelism can also be used in thinking. Rather than have just a single hypothesis, try considering a wide range of possibilities, then eliminating one hypothesis at a time as disconfirming evidence is found.

See also

Natural Selection, Mutation, Change Management