Владислав Педдер – The Existential Limits of Reason (страница 3)

2.3 The Discovery of the DNA Structure and Genes as Units of Inheritance

The discovery of the structure of DNA in 1953 by James Watson and Francis Crick, based on X-ray crystallography data, marked a significant turning point in biology. DNA was decoded as a molecule that encodes genetic information passed down from generation to generation. Genes became the fundamental units of heredity, containing the instructions for synthesizing proteins that play a crucial role in the functioning of an organism.

Genetics further revealed how mutations occur, with random changes in genes leading to alterations in organisms. These mutations can be beneficial, neutral, or harmful, and depending on their impact on the organism’s survival, they can be passed on to the next generation. The process of gene expression and their regulation through epigenetic mechanisms (such as DNA methylation) adds additional layers to our understanding of how organisms adapt to their environment. This intricate interplay of genetic and epigenetic factors shapes the evolutionary trajectory of life..

The significance of mutations and their impact on organisms is revealed through the concept of “negative selection,” which eliminates organisms with harmful mutations, and “positive selection,” which enhances the existence of those better adapted. The inclusion of epigenetics in the modern understanding of evolution allows for a fuller appreciation of how the external environment can influence genetic changes and species adaptation.

2.4 Theory of Multilevel Selection and Modern Understanding of Evolution

The theory of multilevel selection, proposed by scientists such as William Hamilton and Richard Dawkins, significantly expands our understanding of evolution. In his famous book The Selfish Gene (1976), Dawkins suggested that the primary units of evolution are not organisms, but genes, which strive for self-replication and spread. From his perspective, the organism is merely a vessel for genes, and evolution is essentially not about the survival of individuals but about the preservation and dissemination of genetic information passed down through generations.

According to this theory, evolution does not view the organism as an independent goal, but rather as a means for transmitting genes to the next generations. This leads to the concept of the “selfish gene,” where each gene acts as a kind of “instrument” concerned with its own preservation within the population. Thus, evolution operates at the level of genes rather than individual organisms.

An important aspect of the development of this theory is the concept of multi-level selection. Selection can occur not only at the level of individual organisms but also at the level of genes, groups, and even species. In this context, evolution can be seen as a process in which not only the most adapted individuals are selected, but also genetic combinations that increase the chances of survival of populations or groups.

One example illustrating multi-level selection is the phenomenon of organisms with similar traits, such as the “green beard effect.” Imagine a group of animals within a population randomly developing a unique trait – a green beard. This concept, proposed by Richard Dawkins, illustrates how traits that are disadvantageous at the individual level can be preserved and spread through group selection. In this case, individuals with a “green beard” (a symbolic trait that distinguishes them from others) may not have obvious survival advantages, but if such individuals form a group, their shared trait can promote cooperation and support within the group, thereby increasing the chances of survival for its members. Thus, this trait could be advantageous at the group level, even if it does not directly benefit the individuals. The green beard can be selected through group selection, where cooperation or even “signals” for interaction with other individuals emerge within the group, supporting the survival of the whole community. Therefore, group-level evolution can lead to the spread of this trait if it promotes cooperation and social interactions, increasing the chances of survival for the entire group.

Dawkins’ theory also considers the importance of altruism in evolution. He argues that individuals who act in the interest of the group can contribute to the preservation of their genes, even if their behavior does not bring them direct benefit. An individual may help the survival of others, such as relatives or group members, at the cost of their own risks. In this context, if an individual with a green beard helps other members of their group survive, their actions could improve the overall success of the entire group, and these traits would be maintained and strengthened at the group level.

Considering evolution as a process that occurs on multiple levels allows us to include not only organisms but also broader evolutionary units such as populations, ecosystems, and even species. For example, within multicellular organisms or communities of organisms with similar traits (such as behavior or physical characteristics), there is a likelihood that these traits will be maintained through altruistic behavior that promotes the overall success of the group. However, such behavior is important not only for the survival of individual organisms but also for the propagation of their genes at the population level.

One vivid example of such a phenomenon can be symbiosis – a close, mutually beneficial coexistence of different species. When two or more species cooperate with each other, their chances of survival increase, and their traits can be supported and strengthened through evolutionary mechanisms. In this way, traits like the green beard, over the long term, can spread not only at the level of individual organisms but also within more complex biological systems, contributing to the overall survival of the group.

Today, it is believed that selection occurs on several levels:

Genetic level: Selection occurs at the level of individual genes. Genes that promote the successful survival and reproduction of their carriers become established in the population, passed down to future generations. This selection focuses on how specific genetic variations can increase their frequency in the population through their impact on the organism or on their copies in other organisms.

Individual level: Selection acts at the level of organisms. Individuals with traits that increase their chances of survival and successful reproduction are able to pass their genes to the next generation. This leads to the spread of beneficial adaptations within the population and the establishment of traits that enhance individual fitness.

Kin selection: Selection occurs through helping close relatives who share similar genes. Altruistic behavior toward kin can increase the chances of spreading common genes, even if it reduces individual survival chances. This type of selection explains the emergence of cooperative behavior in family groups and colonies.

Group level: Selection occurs at the level of groups of organisms. Groups in which members cooperate and support each other may have an advantage over groups where selfish behavior predominates. Competition between such groups may lead to the selection of cooperative strategies that enhance the success of the group as a whole.

Ecosystem or symbiotic community level: Selection may occur at the level of entire ecosystems or communities made up of interconnected species. In such systems, stable interactions, such as symbiosis, cooperation, and mutual support, can contribute to the successful existence of all members of the community. If an ecosystem or symbiotic community successfully adapts to changes in the environment and maintains its stability, it can contribute to the survival and spread of all the species involved. Although this level of selection is debated, examples of coevolution show that complex communities can form through cooperative and mutually beneficial relationships between different organisms.

Modern research supports the ideas of multilevel selection, showing how cooperation at the group and community levels can contribute to evolutionary success.

2.5 The Role of Randomness and Directionality in Evolution

It is important to note that evolution, as a process, largely depends on random mutations, which can either benefit or harm an organism. However, the presence of directionality in evolution is not entirely excluded. With each generation, species become more adapted to their environment, but this does not occur through predefined goals or projects. Instead, it is the result of interactions between random changes and prevailing ecological and social factors.

Evolution does not have a predetermined goal or final destination. An important point is that it is not aimed at creating perfect beings but simply at adapting organisms to the specific conditions in which they exist. In this sense, evolution is not so much a process of development as it is one of endless adaptations and changes.