Reproduction: Asexual and Sexual
Key Idea: Reproduction is the biological process by which organisms produce new offspring, ensuring the survival of their species. There are two fundamental strategies: asexual reproduction (one parent, no gamete fusion) and sexual reproduction (two parents, gamete fusion).
Asexual Reproduction
Asexual reproduction involves one parent organism producing offspring that are genetically identical to the parent (clones). It does not involve gametes or fertilisation.
Key Features
- Only one parent required
- Involves mitosis (cell division producing identical copies)
- Offspring are genetically identical (clones)
- Generally faster than sexual reproduction
- No need to find a mate
Types of Asexual Reproduction
| Type | Description | Example |
|---|---|---|
| Binary Fission | Parent cell splits into two identical daughter cells of equal size | Bacteria, Amoeba |
| Budding | A small outgrowth (bud) develops on the parent and eventually detaches | Hydra, Yeast |
| Fragmentation | An organism breaks into pieces, each regenerating into a new individual | Sea stars, Planaria |
| Vegetative Propagation | New plants grow from vegetative parts (roots, stems, leaves) | Strawberry runners, potato tubers, ginger rhizomes |
| Spore Formation | Specialised reproductive cells (spores) develop into new organisms | Fungi, Ferns, Mosses |
| Parthenogenesis | An unfertilised egg develops into a complete individual | Honeybees, Aphids, some reptiles |