In diplontic life cycle, the zygote undergoes mitosis and forms a diploid sporophytic stage which is dominant and independent. it includes all seed bearing plants i.e., angiosperms and gymnosperms

whereas, in haplo-diplontic life cycle it shows an intermediate condn. the zygote undergoes meiosis and forms a haploid gametophyte which is dominant and altered with sporophytic stage which is wholly or partially dependent on gametophyte.

Development in Zygote in Organisms with Diplontic Life Cycle:
In organisms with a diplontic life cycle, the zygote undergoes development to form a multicellular diploid organism. This type of life cycle is observed in most animals, including humans, where the zygote develops into an adult organism directly without any alternation of generations.

Fertilization:
- The diplontic life cycle begins with the fusion of gametes during fertilization.
- This fusion results in the formation of a zygote, which is a diploid cell with a complete set of chromosomes.

Cleavage:
- After fertilization, the zygote undergoes a process called cleavage.
- Cleavage involves a series of rapid cell divisions without any significant growth in size.
- These divisions lead to the formation of a multicellular embryo consisting of a cluster of cells called blastomeres.

Gastrulation:
- Gastrulation is the next crucial step in zygote development.
- During gastrulation, the blastomeres rearrange and differentiate to form three germ layers: ectoderm, endoderm, and mesoderm.
- The ectoderm gives rise to the skin, nervous system, and sensory organs.
- The endoderm develops into the digestive system and internal organs.
- The mesoderm forms the musculoskeletal system, circulatory system, and reproductive organs.

Organogenesis:
- Following gastrulation, organogenesis occurs, which involves the formation and differentiation of specific organs and tissues.
- Various signals and interactions between cells and tissues guide the development of specific structures.
- Organs such as the heart, brain, lungs, and liver begin to form during this stage.

Growth and Maturation:
- As the embryo continues to develop, it undergoes growth in size and complexity.
- The cells divide, differentiate, and organize into specific tissues and organs.
- This growth and maturation process continues until the organism reaches adulthood.

Development in Zygote in Organisms with Haplo-Diplontic Life Cycle:
In organisms with a haplo-diplontic life cycle, there are two distinct multicellular stages: the haploid gametophyte and the diploid sporophyte. The zygote plays a crucial role in the development of both stages.

Fertilization:
- Similar to the diplontic life cycle, the haplo-diplontic life cycle also begins with the fusion of gametes during fertilization.
- The fusion of a haploid egg and a haploid sperm results in the formation of a diploid zygote.

Embryo Development:
- The diploid zygote undergoes development to form a multicellular diploid embryo, which represents the sporophyte generation.
- The embryo develops through various stages, including cleavage, gastrulation, and organogenesis, similar to the diplontic life cycle.

Spore Formation:
- Once the diploid embryo has fully developed, it undergoes a process of spore formation.
- The sporophyte undergoes meiosis to produce haploid spores.
- These spores are released into the environment and give rise to the haploid gametophyte generation.

Gametophyte Development:
- The haploid spores