Divergence in biology - what is it? In some cases, populations living in ecologically distinct peripheral environments may exhibit genetic differences from the rest of the population, especially where there is a high diversity of species. Genetic divergence is a biological process in which two or more populations of an ancestral species independently accumulate genetic changes (mutations) to produce survivable offspring. Genetic differences among divergent populations can include mutations that do not affect the phenotype, as well as lead to significant morphological and physiological changes.
Genetic divergence
At the level of molecular genetics, divergence in biology is the genetic changes that occur as a result of speciation. However, the researchers argue that it is unlikelythat such a phenomenon was the result of a one-time and significant dominant mutation at a genetic locus. If it were possible, then these mutations could not be passed on to the next generations. Therefore, more likely is the variant of sequential reproductive isolation, which is the result of multiple small mutations in the process of evolution.
Divergent evolution
According to the theory of evolution, divergence in biology is a relative phenomenon in which initially similar populations accumulate differences in the course of evolutionary development and gradually become more distinct. This process is also known as "divergence" and was described in On the Origin of Species (1859). Even before Darwin, many lines of divergence from the central species type were described by Alfred Russell Wallace in 1858. According to traditional evolutionary theory, divergence serves two main purposes:
- It allows this type of organism to survive in an altered form by exploiting new biological niches.
- This increase in diversity enhances the adaptability of the younger generation to diverse habitats.
These assumptions are purely hypothetical, since it is very difficult and almost impossible to prove them experimentally.
Molecular Divergence
What is it in terms of molecular biology? This is the proportion of nucleotides that differ from each other by two segments of DNA. The percentage may also vary.amino acids between two polypeptides. The term "divergence" is used in this context because there is an assumption that two molecules are descendants of one parent molecule. In the process of evolution, there is not only a divergence, but also a merging of events, such as hybridization and horizontal transfer. And such events occur much more frequently. The molecular mechanisms of evolutionary divergence of genetic material include nucleotide substitutions, deletions, insertions, chromosomal recombinations, transpositions and inversions, duplications, transformations, and horizontal gene transfer. The number of nucleotide substitutions is a simple and useful measure of the degree of divergence between two sequences. In fact, there are several methods available for estimating the number of nucleotide substitutions and constructing a phylogenetic tree showing the evolutionary path of divergence.
Analog of convergence
Divergence in biology is analogous to evolutionary convergence, during which organisms with dissimilar ancestors became similar due to natural selection. For example, flies and birds have evolved to be similar, in the sense that they have wings and can fly, even though their flightless ancestors were completely different. In fact, these two belong to different biological types. A divergence in biology is an evolutionary event in which two morphological or molecular traits arose from a common ancestor. These characteristics were originally the same, but becameheterogeneous in the course of evolution. In the case of discrepancy, there must be some degree of similarity between the two traits to suggest that there was a common ancestor. For rapprochement, on the contrary, there must be a certain dissimilarity, since certain features were borrowed from completely independent ancestors. Thus, the difference between divergence and convergence is difficult to establish.
Divergence in biology: pictures
Divergent evolution (from Latin divergentia - divergence), as a rule, is a consequence of the diffusion of the same species in different and isolated environments. The following examples can be given: most creatures on the planet have upper limbs, humans and primates have arms, vertebrates have legs, birds have wings, fish have fins, and so on. All these organs are used by living organisms in different ways, but their origin is identical. Divergence can occur in any group of related organisms. The greater the number of differences present, the greater the discrepancy. And there are a great many such examples in nature, for example, a fox. If its habitat is the desert, then the coat of an animal of a certain color helps to disguise itself from predators. The red fox lives in the forests, where the "red coat" is combined with the local scenery. In the desert, the heat makes heat transfer difficult, so the fox's ears have evolved to large sizes, so the body gets rid of excess heat. The decisive factor in this is thejust different environmental conditions and adaptation requirements, not genetic differences. If they lived in the same environment, it is likely that they would have evolved in a similar way. Divergent evolution is a confirmation of genetic closeness.
Divergence in nature: examples
Evolution is the process by which organisms change over time. The main feature is that all this happens very slowly and takes thousands or even millions of years. Divergence in biology - what is it? Consider, for example, a change in the human body: someone is tall, someone is short, some have red hair, others are black, some are light-skinned, some are dark-skinned. Like humans, other living organisms also have many variations within the same population.
Divergence is in biology (examples clearly show this) the process of accumulation of gene transformations necessary for survival. An example from real life can be given. There are many types of finches in the Galapagos Islands. When Charles Darwin visited these places, he noted that these animals are indeed similar, but they still have some key differences. This is the size and shape of their beaks. Their common ancestor underwent an adaptive radiation, thus contributing to the development of new species. For example, on one island where seeds were plentiful, bird beaks were the best suited to eating this type of food. On another island, the structure of the beak helped the animaleat insects. After all, many new species emerged, each with its own unique characteristics.
Divergent evolution occurs when it comes to the emergence of a new biological species. As a rule, this is necessary in order to adapt to different environmental conditions. A good example is the human foot, which is very different from the monkey foot, despite their common primate ancestor. A new species (in this case humans) evolved because there was no longer a need to climb trees. Bipedalism produced the necessary changes in the foot to improve speed, balance and confident movement on the earth's surface. Although humans and apes are genetically similar, they have evolved different physical traits necessary for survival.
