What is collective immunity?

Group immunity refers to the resistance of people or herds to infection.

A high level of group immunity means a high proportion of animals resistant to infection in the group. Because the possibility of epidemic disease depends not only on the number of resistant individuals in the animal population, but also on the contact frequency between individuals in the animal population. If 70%-80% of the animals in the group are resistant, there will be no large-scale outbreak.

As for biological groups, there are two meanings:

① Population genetics refers to the genetic composition of a population, that is, the frequency of genes and genotypes appearing in this population. For example, the population of pure varieties is homogeneous and the individuals are homozygous; However, the population of open pollinated species is heterogeneous, and the individuals are heterozygous. Studying the genetic composition of population in crop breeding is helpful to the decision-making of breeding scheme.

② In crop cultivation, the composition of individual groups of crops planted in the same field is antagonistic. This group may be composed of several crops, such as mixed sowing, intercropping or monoculture. It is helpful to guide the high-yield cultivation of crops to study the space occupied by each individual, the composition of its phenotype and the dynamic coordination among individuals.

References:

Group immunity _ Baidu Encyclopedia