There are three types of life cycles depend on the dominant phase. These are Haplontic, Haplo-diplontic and Diplontic life cycles. The steps shown in the question is of Diplontic type of reproductive cycle. In this type of cycle, dominant phase is the diploid. The haploid phase is only represented by short lived gametes.
Explanation: There are basically two types of reproduction: sexual reproduction and asexual reproduction. In sexual reproduction, a diploid zygote is formed by the fusion of a haploid sperm and egg in the process called fertilization. The diploid zygote formed undergoes mitosis to form a diploid adult. Mitosis is a type of division in which a cell divides to produce two identical daughter cells each with the same number of chromosomes as the parent cell. This kind of cell division is necessary in growth and development. The diploid adult undergoes meiosis to produce haploid sperm and egg. Meiosis is a type of division in which a cell divides twice to produce four identical daughter cells each with half the number of chromosomes as the parent cell. Meiosis occurs only in the gametes. The haploid sperm and egg fuses in a process known as fertilization to form a diploid zygote.
