Outcome:
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Sexual reproduction involves the formation of offspring from two separate sources (a male parent and a female parent)
- Advantages: Produces genetic variation in the offspring – meaning there will be increased species richness
- Disadvantages: Requires two parents and takes longer to occur (involving an increased energy expenditure by the parent)
Gametogenesis
Sexual reproduction requires the formation of specialised sex cells (called gametes), which form via the process of meiosis
- Males typically produce smaller gametes (sperm) which combine with the larger gametes (ova) produced by females
- Gametes contain half the genetic information of the parent (haploid) and combine to form a diploid offspring that is a genetic amalgam
Fertilisation
The fusion of two gametes is called fertilisation and can occur internally (via copulation) or externally (via mass spawning)
- External fertilisation incurs a lower survival cost to the parents, but offspring are more susceptible to the environment while developing
