What is the relationship between population evolution and self organizing evolution?

1.Characteristics of energy flow in communities: In the early stage of ecological succession, the energy input of the community is greater than the dissipation, so that it accumulates in the system in the form of biomass and debris.

2.Community development and material cycle: In the early stage of succession, short-lived plants were the mainstay, and the nutrient regeneration role of residues in the nutrient cycle was not very important, the organic phase of the cycle was weak, the nutrient entry and exit system was easy, the nutrient cycle showed the characteristics of openness, the amount of nutrient circulation was small, and the exchange of nutrients between the biotic and abiotic parts was faster.

3.Nutritional structure of the community: from the perspective of nutritional structure, the food chain has developed from a relatively simple chain structure to a complex network structure, which makes the community more stable, and in the utilization of net production, from the early stage to the plant-fed food chain, the contact between the members of the organisms is less, and the later stage is dominated by detrital food, and a closer union and mutual adaptation relationship between animals and plants have been established, and the structure of the food chain is complex, forming a large and complex network organic structure.

4.Community structure and species composition: Biological communities tend to develop more complex, diverse and stable outcomes and compositions.

5.Community stability: Due to the enhancement of species diversity and nutrient structure complexity in the succession process, the feeding activities, population density changes, and nutrient cycling of herbivores tended to be stable through the negative feedback regulation of biological control, so that the community structure and function tended to be stable, and the ability to resist aliens was gradually enhanced.

The problems of small populations are mainly manifested in 1) loss of genetic variation 2) inbreeding decline 3) outbred decline 4) loss of evolutionary plasticity 5) effective population size 6) inequality ratio 7) variation due to reproduction 8) population fluctuations and bottleneck effects 9) population changes 10) environmental changes and natural disasters 11) extinction vortex.

The reasons for this may come from three aspects: 1) genetic problems due to lack of genetic variability, inbreeding, and genetic drift; 2) Instability of population populations due to the arbitrary elimination of birth and mortality rates 3) Environmental fluctuations caused by predation, competition and competition, changes in disease and food**, and irregular occurrence of single events, such as fires, floods, droughts, etc., which lead to natural disasters in Biliang.

Because after the succession of the community reaches a relatively stable stage, the composition of species in the community is still in a dynamic change.

Over time, some species in a biome invade and others disappear, and the composition of the community and the environment develop sequentially in a certain direction, which is called succession.

The main signs are:

The species composition of the community changed; Or the process of gradually replacing one community with another in a given area.

The most important feature of plant community dynamics. The process is mostly composed of seasonal and year-to-year changes in plant communities. It is a temporal process in which a variety of different plant communities are sequentially distributed in the same area on the surface of the earth.

a. Natural selection is directional and determines the direction of biological evolution, but the variation of organisms is not directional, and a is wrong;

b. The essence of biological evolution is the directional change of gene frequencies in populations, b errors;

c. Reproductive isolation is a sign of new speciation, c. Correct;

d. Biodiversity includes genetic diversity, species diversity and ecosystem diversity

Population ecology is the science that studies the interaction between population dynamics and the environment.

Population ecology has its origins in demography, applied entomology, and aquatic resources. The model of Lotka-Volterra (1925, 1926) was a milestone in theoretical ecology and thus entered the ** era. In the first half of the 20th century, it developed from a descriptive discipline to an experimental, quantitative, and theoretical discipline.

The discussion of the theory of population regulation at the 1957 International Conference in Cold Spring Harbor marked the beginning of population ecology as the mainstream of ecology. Since then, with the development of ecosystem ecology and becoming the mainstream, population ecology is still the most developed and active field of ecology in terms of theory and methodology. As a system, the in-depth study of the interaction between population and the physical environment, its spatiotemporal dynamics and regulatory mechanism, its genetic composition and evolution, and behavioral adaptation is the basis for understanding the structure, function, dynamics and regulation of communities and ecosystems.

Plant population ecology has marked the emergence of plant population ecology since Harper's (1977) model of plant population dynamics based on plant life history, followed by the publication of works on plant population ecology by Solbring (1979), Mortimer (1981), Silvertown (1982) and Hedrick (1984).

The research of modern population ecology includes the spatiotemporal dynamics of populations, the interaction process between populations, and the regulation mechanism of populations, which is still the core and foundation of ecological research.