Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Pollination: The transfer of pollen grains from the anther to the stigma of a flower. It is categorized into Self-pollination (same flower or plant) and Cross-pollination (different plant of the same species).
Fertilisation: The process of fusion of the male gamete with the female gamete () to form a . This occurs inside the ovule after the pollen tube grows through the style.
Post-Fertilisation Changes: After fertilisation, the develops into an embryo. The develops into a seed, and the grows into a fruit.
Agents of Pollination: Includes biotic agents like insects (bees, butterflies) and abiotic agents like wind and water. Wind-pollinated flowers often have light, non-sticky pollen grains and feathery stigmas.
Seed Dispersal: The movement or transport of seeds away from the parent plant to prevent competition for sunlight, water, and minerals. Common methods include dispersal by Wind (e.g., ), Water (e.g., ), Animals (e.g., ), and Explosion (e.g., ).
📐Formulae
💡Examples
Problem 1:
Explain the role of the pollen tube in the fertilisation process.
Solution:
The pollen tube acts as a conduit for the male gamete.
Explanation:
Once a pollen grain lands on a compatible stigma, it germinates to produce a pollen tube. This tube grows through the to reach the . The male gametes travel through this tube to reach the where the fusion with the cell occurs.
Problem 2:
Identify the mode of dispersal for a seed that is hairy and very light.
Solution:
Dispersal by Wind.
Explanation:
Seeds of plants like (Madar) or have hairy outgrowths or wings that increase their surface area, allowing them to be easily carried away by wind currents over long distances.
Problem 3:
Why is seed dispersal necessary for the survival of plant species?
Solution:
To avoid overcrowding and resource competition.
Explanation:
If all seeds fell under the parent plant, they would compete for , minerals, and sunlight. Dispersal ensures the species can invade new habitats and reduces the between the parent and the offspring.