Gymnosperm Life Cycle

Gymnosperm Life Cycle

• Plants that reproduce using seeds are categorized into angiosperms and gymnosperms.
• Angiosperms are flowering plants, while gymnosperms are referred to as plants with naked seeds.

Alternating Generations

• Gymnosperms alternate between two life stages: haploid (one set of chromosomes) and diploid (two sets of chromosomes).
• Haploid stage consists of male and female gametophytes (sex cells).
• Diploid stage is represented by the adult tree after gametophytes have joined and developed.

Gymnosperm Reproduction

• The pinecone is the female reproductive structure of a gymnosperm.
• Pollen grains contain one set of the tree's chromosomal information and are carried by wind to the female structure.
• Fertilization occurs when pollen meets the female gametophyte, resulting in a diploid seed.

Gymnosperm Sporophytes

• The adult tree represents the diploid stage of the conifer life cycle of a gymnosperm and is referred to as the sporophyte.
• Sporophytes produce haploid gametophytes through meiosis.
• Megagametophytes produce female gametes (eggs), while microgametophytes produce male gametes (sperm).

Gymnosperm Fertilization Process

• Male cones contain microspores (pollen grains) that produce male gametes.
• Female cones contain megaspores that produce eggs.
• Fertilization occurs when microgametophyte and megagametophyte meet, resulting in a diploid embryo.

Gymnosperm Seeds

• Gymnosperm seeds are naked and lack a protective coating like angiosperm seeds.
• Seeds develop under the scale of the female cone after fertilization.

Gymnosperm Life Cycle Diagram

• The life cycle of a gymnosperm involves multiple stages: adult sporophyte, megasporophyte, microsporophyte, meiosis, megaspores, microspores, gametophytes, fertilization, and the development of a new sporophyte.