Advantages & Disadvantages of Sexual & Asexual Reproduction (AQA GCSE Biology)

Revision Note

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Biology Lead

Advantages	Disadvantages
Increases genetic variation	Takes time and energy to find mates
The species can adapt to new environments due to variation, giving them a survival advantage	Difficult for isolated members of the species to reproduce
Disease is less likely to affect the population (due to variation)

An additional advantage of sexual reproduction is our ability to use it and control it for our own needs:
- Natural selection can be speeded up by humans in selective breeding to increase food production
- We have controlled sexual reproduction in cows and selectively bred them to produce offspring that produce more milk and more meat than they would have under natural conditions

Advantages	Disadvantages
The population can be increased rapidly when conditions are right	Limited genetic variation in population - offspring are genetically identical to their parents
Can exploit suitable environments quickly	The population is vulnerable to changes in conditions and may only be suited for one habitat
More time and energy-efficient	Disease is likely to affect the whole population as there is no genetic variation
Reproduction is completed much faster than sexual reproduction

As only one parent is needed, asexual reproduction is more time and energy-efficient than sexual reproduction, as asexually reproducing organisms do not need to find a mate

Some organisms reproduce by both methods depending on the circumstances. For example:

Malaria is caused by parasites that are carried by mosquitoes
The parasites are transferred to a human when the mosquito feeds on the human’s blood
These malarial parasites reproduce asexually in the human host, but sexually in the mosquito

Many fungi reproduce both asexually and sexually
These species of fungi release spores, which develop into new fungi
These spores can be produced via asexual or sexual reproduction
Spores that are produced via sexual reproduction show variation (they are genetically different from each other)

Many plants produce seeds via sexual reproduction but are also able to reproduce asexually
They reproduce asexually in different ways:
- Some plants (eg. strawberry plants) produce ‘runners’ (stems that grow horizontally away from the parent plant, at the end of which new identical offspring plants form)
- Some plants (eg. daffodils) reproduce via bulb division (new bulbs form from the main bulb underground and then grow into new identical offspring plants)

Runners, IGCSE & GCSE Biology revision notes

Some plants grow side shoots called runners that contain tiny plantlets on them. These will grow roots and develop into separate plants

Bulbs and tubers, IGCSE & GCSE Biology revision notes

Some plants develop underground food storage organs that will develop into next years plants – bulbs are an example of this

to absolutely everything:

the (exam) results speak for themselves:

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