Definition:
Parthenogenesis is a type of asexual reproduction in which a new individual develops from an unfertilized egg (ovum).
- No fusion of gametes (no fertilization).
- Offspring are usually haploid (in some species diploid).
- Common in certain invertebrates, reptiles, and plants.
Types of Parthenogenesis
- Natural Parthenogenesis
- Occurs naturally in some organisms.
- Examples: Honey bees, ants, aphids, rotifers, some lizards, turkeys.
- In honey bees:
- Fertilized eggs → females (workers/queens).
- Unfertilized eggs → males (drones).
(This system is called haplodiploidy).
- Artificial Parthenogenesis
- Induced in laboratory by physical or chemical means (e.g., temperature shock, chemicals, pricking the egg).
- Used in research and biotechnology.
Based on Ploidy of Offspring
- Haploid Parthenogenesis (Arrhenotoky)
→ Males develop from unfertilized eggs (e.g., bees). - Diploid Parthenogenesis (Thelytoky)
→ Females develop from unfertilized eggs (e.g., some lizards, plants). - Amphitoky
→ Both males and females can develop parthenogenetically.
Examples in Different Groups
- Insects: Bees, ants, aphids.
- Reptiles: Lizards, Komodo dragon (rare cases).
- Birds: Domestic turkey (rare).
- Plants: Certain angiosperms (through apomixis).
Mnemonic to Remember
“Partheno = Virgin Birth” → Think of it as reproduction without fertilization.
Parthenogenesis is the development of an embryo from an unfertilized egg, seen in bees, ants, aphids, some reptiles, and plants. It may produce haploid males or diploid females depending on the species.
Parthenogenesis