Oogamy

Oogamy is sexual reproduction in which a large, nonmotile egg is fertilized by a smaller, motile sperm. It is a form of anisogamy.

Sperm: A male reproductive cell that typically carries genetic material to an egg. In oogamy, the sperm is the smaller, motile gamete that reaches the egg.
Anisogamy: Sexual reproduction involving gametes that differ in size or form. Oogamy is a specialized form of anisogamy with a nonmotile egg and motile sperm.
Evolution of anisogamy: The evolutionary emergence of sexual reproduction with differently sized gametes. Oogamy is one outcome of evolutionary divergence between small and large gametes.
Human reproduction: The biological processes through which humans produce offspring. Human reproduction is a familiar example of fertilization between a large egg and small sperm.
Egg cell: A female reproductive cell that can fuse with a sperm to form a zygote. Its large size and lack of motility distinguish the egg in oogamy.
Isogamy: Sexual reproduction involving gametes that are similar in size and shape. Its similar gametes contrast with oogamy’s sharply unequal egg and sperm.
Disruptive selection: Natural selection that favors individuals at both extremes of a trait over intermediate forms. This model helps explain how selection can favor both numerous small gametes and fewer large ones.
Plant reproduction: The processes by which plants produce offspring sexually or asexually. Oogamous reproduction occurs in many plant lineages, with specialized sperm delivery mechanisms.
Zygote: The cell formed when two gametes fuse. The zygote is the immediate product of egg and sperm fusion.
Heterogamy: Sexual reproduction involving unlike gametes, often differing in size or structure. This broader term helps situate the specialized gamete difference seen in oogamy.

Linked from 7 pages