Heredity and Evolution — Science STD 10 — Question

Classification involves grouping of organism into a formal system based on similarities in internal and external structure or evolutionary history. Two species are more closely related if they have more characteristics in common. For example, in a family, a brother and sister are closely related and they have a common ancestor i.e. their parents. A brother and his cousin are also related but less than brother and sister because the brother and his cousin have a common ancestor i.e. grandparents. Grandparents were second generation whereas parents are first generation.