How did species come into being and what is the concept of species?

The concept of species is a general term for organisms that have the same gene pool.

Species are the basic units of taxonomy. A species is a natural group formed by the same organisms that reproduce with each other, are reproductively isolated from each other and occupy a certain ecological niche in nature. Species emphasize the ability of individuals to mate and produce fertile offspring.

A species can have multiple populations.

The range is different: species are sometimes equal to population, but in most cases larger than the concept of population, there may be multiple populations within a species, and population is an ecological concept, not the same as taxonomic concepts such as subspecies variants.

Humans have long been able to identify objects and give them names. In the early Han Dynasty, Erya divided animals into four categories: insects, fish, birds, and beasts: insects include most invertebrates; Fish include fish, amphibians, reptiles and other lower vertebrates, whales, shrimps, crabs, shellfish, etc.; Birds are birds; Beasts are mammals.

This is the earliest classification of animals in ancient China, and the generation period of the four types of names seems to be no later than the Western Zhou Dynasty. This classification, compared with Linnaeus's (1758) six-class system, is missing only two classes (amphibians and helminths).

The three basic links of speciation are: heritable variation is the raw material for speciation; Choice determines the direction of speciation; Isolation is a necessary condition for speciation.

Cause of speciation:

The evolution of complex life has actually come at a significant cost of energy, i.e., more energy is needed to sustain the same quality of life activity. Conversely, if it were not for the existence of an oxidizing atmosphere, life on Earth would probably remain in simple life forms (bacteria) with low energy consumption.

Because the growth efficiency of the anaerobic food chain is 1 4 of the aerobic food chain, and oxygen should allow the existence of a longer food chain on Earth. Although the mass of microorganisms is small, the metabolic rate per unit body weight is very fast. Therefore, if the metabolic rate is the strongest selection pressure, then the microbes will have an absolute advantage, which is why microbes dominate the world of decomposers.

Since energy (utilization) declines progressively along the food chain, the more efficient the energy use of the food chain (aerobic), the longer the food chain is allowed. In this way, the emergence of the aerobic food chain provides an important energetic basis for the complexity of the ecosystem's food web (and therefore the diversification of species).

According to the time required for seed formation and the presence or absence of intermediate stages, it can be divided into gradual seed formation and sudden seed formation. According to the geographical characteristics of speciation, it can be divided into different species formation, adjacent species formation and co-species formation. If we consider time vectors, especially from the point of view of systematics, then the formation of species can also be divided into inheritance and differentiation speciation.

Some of these different distinctions cover each other, such as inherited and differentiated speciation, and the different speciation is mostly gradual, and the sudden speciation is usually independent of geographical isolation factors, and can be formed in the same place, in different places or in adjacent places.

Inherited and differentiated speciation Inherited speciation refers to the gradual evolution of one species into another in the same area, and the speciation time is very long, and the various links of gradual evolution can be seen. Differentiated species morphology refers to the gradual differentiation of a species into geographic subspecies or ecological subspecies within its distribution range, and the development of two or more new species.