Speciation in nature is combined with the laws of natural selection, which were studied and developed by Charles Robert Darwin.
Speciation is the process of the emergence of newer biological species and their changes over time according to the theory of natural selection.
Moreover, if there is a genetic incompatibility, that is, the inability to offspring when crossing, this is called interspecific barrier. The basis of speciation, according to the synthetic theory of evolution (STE), is hereditary variability, where the leading factor is natural selection.
There are two options for speciation:
• geographical (allopatric);
• environmental (sympatric).
Examples of ecological speciation are widespread in nature. Let's consider some of them.
Natural situation
Biological practitioners point out that examples of environmental speciation are not always pronounced. There are groups of individuals that do not cross or cross slightly regardless of background conditions. For example, black grouse or capercaillie are completely dissimilar species, but they can genetically interbreed. The following examples are: dog, wolf and jackal; most species of deer. In speciation (geographical, environmental), the main event is the appearance of natural, actual isolation of biomorphs, even if they live in the same area.
Ecological speciation
This concept denotes the process of the formation of new species in coincident territories. It is the ecological features of development that prevent them from interbreeding, because populations occupy different ecological niches. How should this be understood? In nature, in different variants, examples of ecological speciation are manifested in the comparison of urban and rural swifts. If they are in the same cage, then they will not have offspring. They have different morphological and physiological characteristics.
The development of signs
The most obvious example of ecological speciation is the formation of additional traits of one species, but in different territories.
For example, there are species of buttercups and tradescantia that have adapted to grow in different conditions - fields, meadows and along river banks, in different natural ranges. Polyploids are also observed, in which the number of chromosomes is different. In animals, convergence occurs - the convergence of signs, and similar structural features of the body.
Such examples of ecological speciation are also observed in nature in the structure of the body forms of fish: cartilaginous sharks, ichthyosaurs (extinct) and dolphins. This is the result of convergence in animals belonging to different classes.
Final conclusion
In nature, the completion of speciation is considered reproductive isolation in the elimination of existing obstacles, regardless of geographic or environmental factors. Whether a new generation will exist, disappear or split into small biological groups depends on the interspecific relationships that have arisen. Examples of ecological speciation show that biodiversity in nature is necessary for evolutionary development.