Evolution: Function, Tasks, Role & Diseases

Evolution means development. Related to humans, it means the development from animal ancestors through prehumans and early humans to present-day humans. The biological name of the species is Homo sapiens. By a “species” biology understands a community of living beings that can reproduce among themselves.

What is evolution?

Evolution means development. In relation to humans, it means the development from animal ancestors through prehumans and early humans to present-day humans. The phylogenetic development of man can be considered in the context of the development of vertebrates and mammals. According to the theory of Charles Darwin formulated in the 19th century, species change respectively develop under the influence of mutation and selection. Mutations are random changes in the genome that can be caused, for example, by chemical or physical effects. If these changes affect the reproductive cells, i.e. the egg or sperm, they are passed on to the next generation at fertilization. Most of these mutations are not viable. However, if the mutation does not result in a life-threatening dysfunction in the offspring, it can be beneficial, detrimental, or have no effect at all on the survivability of the individual. Advantageous mutations can, for example, have the effect that the carrier of the new trait is better able to assert itself in the environment, as well as to bring more and more resistant offspring into the world in the course of life. Thus, over time, through positive selection, the new trait would spread through the population. This could also be a first step of change toward a new species.

Function and task

Remains of the first cell-nucleated life forms have been found in rock layers of the Earth’s primeval period. They are over 3 billion years old. The evolution to increasingly complex forms of life took place in the sea. However, it was not until the Cambrian period about 570 million years ago, the beginning of the Earth’s primeval period, that most of the animal phyla living today were apparently present. These include mollusks such as snails, arthropods such as crabs, and cnidarians such as jellyfish and corals. Fossil remains of vertebrates are only known from the Ordovician 500 million years ago. Soon, plants and animals began to colonize the land as well. In the Devonian, about 400 million years ago, amphibians were the first vertebrates to colonize the land. From the Middle Ages, the age of the dinosaurs, we already know the first fossils of small mammals. These probably had the advantage over the alternately warm lizards that they could regulate and maintain their body temperature independently. Thus they could move nimbly even at low temperatures. This was an important survival and adaptive advantage. Even today, large lizards and amphibians are found only in warm climates, while mammals have been able to spread as far as arctic regions. Likewise, the reproductive mode of mammals represents a decisive evolutionary advantage, because the embryo can develop protected in the body of the mother and the offspring are cared for at the beginning. Finds of prosimians are already known from the Cretaceous period about 140 million years ago. After the extinction of the dinosaurs at the end of the Cretaceous period, birds and mammals were able to develop further. They were able to colonize almost all habitats during the Tertiary period about 65 million years ago. Which line of development led directly to today’s humans can only be deduced by comparing fossil finds. With new finds, therefore, older ideas often have to be reviewed and revised. It is assumed that Proconsul or Propliopithecus, which was about the size of a baboon and lived 20 to 30 million years ago, was an ancestor of today’s primates, which biologically include humans. A little more small-step considered a very slow evolution from generation to generation takes place. Thus, all living beings are permanently subject to the influences of the environment, the conditions of which inscribe themselves almost imperceptibly in the bodies. The fields of epigenetics and acceleration bear witness to this.

Diseases and ailments

The evolution to humans and the genus Homo may also have resulted in developmental lineages that became extinct. In part, this is thought to have occurred in Neanderthal man (Homo neandertalensis).However, some researchers also assume that this mixed with Homo sapiens and merged into the population. As typical human characteristics we call the upright walk, the language, the tool use and the development of cognitive abilities, which went along with the development of the brain. However, such abilities can also be found to some extent in animals, as shown, for example, by astonishing results of science in which the abilities of animals have been intensively trained. One of the triggers of human development may have been the spread of steppes 7.5 million years ago. It favored the upright gait, which provided a better overview. At the same time, this freed up the hands for the use and manufacture of tools. The hand has since evolved into a specialized gripping tool that can be used to better prepare and process food. Thus, a strong jaw was also no longer so important and the brain skull could occupy a larger space. The alternation of ice ages and warm periods about 2 million years ago at the beginning of the Quaternary period made demands on the adaptability of living beings, which man was particularly well able to cope with. He was able to protect himself with suitable clothing and dwellings and to pass on his experience as an important store of knowledge within the social group. However, the many advantages of human evolution, which today enable us to actively shape our environment, also brought about difficult changes. One of them is the enlargement of the skull, which led to the fact that humans are born in pain. Thus, the maximum size for birth by natural means has long been reached.