Self-pollination and Cross-pollination Flashcards
Definition of pollination
Transfer of pollen grains from the anther of a flower to the stigma of a flower
Definition of self-pollination
Transfer of pollen grains from the anther of a flower to the stigma of
(a) the same flower (of the plant)
(b) a different flower on the same plant
Features of flowers that favour self-pollination
- flowers are bisexual with anthers and stigmas maturing at the same time
- stigma is situated directly below the anthers
Definition of cross-pollination
Transfer of pollen grains from the anther of a flower to the stigma of a flower on a different plant of the same species
Features of flowers that favour cross-pollination
- some plants bear either only male or female flowers
- in bisexual flowers, anthers and stigmas may mature at different times
- in bisexual flowers, stigmas may be situated some distance away from the anthers so that self-pollination is unlikely
Genetic variation of self-pollination
Negative: less genetic variation in offspring means offspring less able to adapt to changes in environmental conditions
Positive: advantageous physical characteristics of parents more likely to be inherited by offspring
Genetic variation of cross-pollination
Positive: more genetic variation in offspring means offspring is more able to adapt to changes in environmental conditions
Energy and resource input for self-pollination
Positive: less energy and resources used by plants to produce pollen
Energy and resource output for cross-pollination
Negative: more energy and resource used by plants to produce pollen
Dependence on external factors for self-pollination
Positive: less dependent on external factors such as animals and wind for pollination, therefore higher probability that pollination will occur
Dependence of external factors for cross-pollination
Negative: more dependent on external factors such as animals and wind for pollination, therefore lower probability that pollination will occur
