In evolutionary lineage which one is important cross pollination or self pollination? What do you think, give reasons in support your answers.
Answers
Answer:
cross pollination
Explanation:
because it causes variation
Answer:
Explanation:
Cross Pollination: The transfer of pollen grains from the anther of the flower of one plant to the stigma of the flower of another plant of the same species is known as cross-pollination. As the pollination occurs between flowers of two different plants, genetics recombination is found in this allogamy.
Advantages:
(1) Cross-pollination brings about genetic recombination resulting into the origin of new varieties.
(2) The offspring produced through cross-pollination are healthy and stronger due to hybrid vigour.
(3) Numerous crop plants (such as sunflower, mustard, clover etc.) give higher yields if only cross-pollination is allowed to occur in them.
(4) Variations are produced due to cross-pollination resulting into the origin of disease resistant plants.
Disadvantages:
(1) Cross-pollination depends on the agents, hence, uncertainty is always there.
(2) Cross-pollination is not beneficial from economic point of view. The plants waste a lot of energy on various contrivances required to ensure cross-pollination and there is huge waste of pollen grains in this process.
When the pollen is transferred from the anthers of a flower to the stigma of the same flower, it is called as self- pollination. This form of pollination is common in hermaphrodite or dioecious plants which contain both male and female sexual parts on the same flower.
In self-pollinating plants, there is less dependence on the external factors to cause pollination. These plants depend on wind or other smaller insects that visit the flower regularly. In self- pollinating flowers, the anthers, and stigma are of similar lengths to facilitate the transfer of pollen. Self – pollination can be further divided into two types:
Autogamy– In this type of self-pollination, the pollen is transferred from the anthers of one flower to the stigma of the same flower.
Geitonogamy– In this type of self- pollination, the anthers are transferred from the anthers of one flower to the stigma of another flower but on the same plant.
Advantages of self – pollination
In self- pollination, there is no diversity in the genes and therefore the purity of the race is maintained.
The plants do not depend on external factors for pollination and even smaller quantities of pollen grains produce have a good success rate in getting pollinated.
Self- pollination ensures that recessive characters are eliminated.
Disadvantages of self- pollination
Since there is no mixing up of genes, there are no new characters or features that are introduced into the lineage of the offsprings.
Self- pollination is said to reduce the vigor and vitality of the race as there are no new features introduced.
Without new characters introduced, the resultant offsprings’ immunity to diseases reduces.
HOPE IT HELPS YOU
PLEASE MARK ME AS BRAINLIEST