IB Biology Exam Prep

Answer: C, Population. A group of species in a localized area form a population in the same manner humans in a city form a population.

Key Takeaway: Ecology studies interactions between individuals. Since it takes more than one organism to have an interaction, the basic ecological unit is the population. A population is a group of individuals that interbreed and share the same gene pool. Being members of the same species does not make all of those members a population. A population on exist if there is an intricate interact being the members of the species in an area.