Evolution theory is such as misunderstood concept. Apart from mixing up is and ought, many get stuck up over animals. In fact evolution theory can be applied to everything which reproduces. This not only applies to animals but to fungi, plants, algae and microorganisms too. No living organisms’ existence can be taken for granted. All have a common origin and have changed over time.
Evolution is something happening to populations of lifeforms. Individual genetic differences arise randomly in a population. Some of these mean the carrier has more surviving children. Such hereditary characters get more common over time. As time goes this can result in the emergence of considerable changes. These arise though gradual modification of already existing forms of organs and abilities. It is not possible for evolution to invent something entirely new. On the other hand, characteristics don’t have to exist in their current form. They can still be useful.
Speciation is usually about a population dividing in two. Changes then accumulate in different populations. Either because different characteristics mean an advantage in different environments. Or else it is about chance. Gradually they may lose the ability to reproduce with each other. It happens single individuals give rise to new species. But this only applies to beings which can conceive themselves. There are lifeforms which reproduce trough division too. However, one then has to use physical resemblance to define a species.
One may naturally wonder how eusociality arose. The explanation is how large part of their genes the animals share with their siblings. In at least some insects, females have two sets of genes. The males only have one which they entirely transfer to each child. The result is full sisters sharing 3/4 of their genes. Half-sisters share as many genes as females do with their daughters. Females helping their mother getting more daughters will then pass on more of their genes. At the same time, it is advantageous to the group if its members are more diverse. All workers in a beehive are for this reason full or half-sisters. Same applies to worker-ants and different forms of termites.
In mammals it is both sexes which have two sets of genes. Normally this means siblings only share half of their genes. This is no more than they share with each of their children. The only mammals which are eusocial are the naked mole-rat and the Damara mole-rat. This behaviour works for them because they are severely inbreed. This makes them share considerably more genes with their siblings than with their own children. Then eusociality can evolve in the same way as in insects.
In species where most can reproduce a different type of cooperation can arise. It is then a matter of a favour for a favour. One example of this is birds flying in V formation. It becomes easier for birds to fly if they fly diagonally behind another one. But for everyone to earn from it everyone must more or less take turn flying first. The flock member who never flies first I think would be ostracised. Alternatively, this cooperation only works as long as those taking advantage remains few. The origin of human society can also be explained this way.
Uploaded on the 29th of January 2024.
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