Advantages of sexual reproduction: produces variation in the offspring; if the environment changes variation gives a survival advantage by natural selection; natural selection can be speeded up by humans in selective breeding to increase food production. • Advantages of asexual reproduction: only one parent needed; more time and energy efficient as do not need to find a mate; faster than sexual reproduction; many identical offspring can be produced when conditions are favourable. • Some organisms reproduce by both methods depending on the circumstances. Malarial parasites reproduce asexually in the human host, but sexually in the mosquito. Many fungi reproduce asexually by spores but also reproduce sexually to give variation. Many plants produce seeds sexually, but also reproduce asexually by runners such as strawberry plants, or bulb division such as daffodils.