define cross pollination and self pollination
state advantages and disadvantages?
Answers
cross pollination
The transfer of pollen from the male reproductive organ (an anther or a male cone) of one plant to the female reproductive organ (a stigma or a female cone) of another plant. Insects and wind are the main agents of cross-pollination
ADVANTAGES
Causes variation in gene pool thus giving more survival advantage to the species.
Seeds are more viable and healthier with better germinating capacity.
Scope for Evolution
Breed new variety of species
DISADVANTAGES
Consumes more time and effort.
Natural process of pollination becomes delayed in this case.
SELF POLLINATION
the transfer of pollen from the anther to the stigma of the same flower, another flower on the same plant, or the flower of a plant of the same clone.
ADVANTAGES
large number of individuals are produced and
traits are genetically identical so advantageous traits are not lost.
Self pollination are generally faster.
Less chance of failure of pollination.
DISADVANTAGES
No variations occurs if plant gets hit by a disease there is no possibility of survival and population decreases.It does not result in creation of new species. Continuous self pollination results in weak progeny
Here is your answer...
↓↓↓↓↓↓↓↓↓↓
Self Pollination...
Pollen grains from an anther of a flower may be transferred to the stigma of the same flower (or onto the stigma of another flower of the same plant). This is described as self Pollination.
→ The possibility of this occuring in the same flower is sometimes reduced by the anthers releasing their pollen grains before the stigma are ready to receive pollen.
→ In absence of a suitable agent of Pollination,it ensures that the plant survives for another generation.
→ There is much greater chance of the offspring being produced with genetic defects.
-----------------------------------------------------
Cross Pollination...
This is when pollen grains are transferred from anther of a flower to the stigma of a flower on a different plant of the same species.
→ Offspring show natural variation that allows the plant species to adapt to changes in the environment and thus to evolve.
→ If plants are rare and grow at considerable distance from one another, reproduction may not occur.
→ There may be an absence of pollinating agents for time that pollen is being released.
Pollination may be brought using different agent for carrying the pollen ( two most common are wind and insect).
________________________
I hope it helps you...
________________________