NEET Class neet Answered

A deme is a smaller group within the population that can freely interbreed.

A population is usually made of several demes that are partially isolated from each other. Mostly, a geographical barrier limits gene flow between the demes, but not sufficiently to result in speciation. Enough gene flow occurs between demes ensuring that all of its members remain the same species. Example: Adivasis are a smaller group within a population of human beings.

A cline is the gradual change in the phenotypes and genotypes of a species across a geographical gradient.

When a species is distributed across a large geographical area some of its members will occupy areas with slightly different environmental conditions than others. Allele frequencies and traits might vary slightly across the geographical gradient because of different selection pressures. Despite genetic and phenotypic differences, members of a cline are all still the same species because each member can interbreed with its immediate neighbours resulting in gene flow through the entire population. Example: Different breeds of dogs.