Pollination

Question 1

Define pollination

Answer 1

The transfer of pollen grains from the anther to a mature stigma of a plant of the same species. It brings the pollen grains (the male gametes) to the female part of the flower and results in fertilisation.

Question 2

What is self pollination?

Answer 2

The pollen from the anthers of a flower is transferred to the mature stigma of the same flower or another flower on the same plant

Question 3

What is cross pollination?

Answer 3

Most angiosperms use cross pollination in which pollen is transferred from the anthers of one flower to the mature stigma on another flower or another plant of the same species.

Question 4

Give 3 genetic implications of self fertilisation. (Inbreeding)

Answer 4

• depend on independent assortment and crossing over during meiosis for genetic variation so there is less genetic variation than cross fertilised species.
• greater chance of harmful alleles that are recessive being bought together
• advantage is that it can preserve successful genomes suited to a relatively stable environment

Question 5

Give 3 implications of cross fertilisation (outbreeding)

Answer 5

• combines gametes from two individuals as well as events in meiosis and mutation so more genetic variation
• reduces production of harmful alleles
• great evolutionary significance - some genomes are more successful than others allowing species to survive in changing environments.

Question 6

How do plants ensure cross pollination?

Answer 6

• dichogamy. The stamen and stigma ripen at different times. Protandry = stamens ripen first. Protogyny = stigma ripens first.
• anther below stigma
• genetic incompatibility
• separate male and female flowers on same plat
• separate male and female plants