Pollination and seed spreading | Year 3 Science PDF Download

Pollination 

• Many plants depend on insects like bees for reproduction.
• For a flower to produce a seed, it must be pollinated, which involves the transfer of pollen from one flower to another.
• Bees play a crucial role in transporting pollen between flowers.

Why are bees so important? 

• Bees play a crucial role in helping plants reproduce, which is vital for all life on Earth. 
• Flowers attract bees by having colorful petals and a pleasing scent. 
• Some flowers offer a sweet treat called nectar to bees as well. 

Flowers and Seed Production

• Flowers produce seeds after the pollen has been transferred from one flower to another. The losing flower goes through a process where it no longer requires its colorful petals, scent, or nectar, signaling its impending death.
• Before wilting completely, the flower initiates the production of seeds, which serve as essential components for various food items such as bread and breakfast cereals.
• Some seeds are enclosed within fruits like apples, plums, and pears, which are cultivated and consumed by humans.

Seed Dispersal Mechanisms

• Plants disperse their seeds through various methods collectively known as seed dispersal. This process ensures the propagation and survival of plant species.
• Wind dispersal is a common mechanism where seeds are designed to float, glide, or spin through the air, aiding their transportation to new locations.

Examples of Seed Dispersal

• Wind Dispersal: Seeds of dandelions and maple trees are lightweight and equipped with structures that help them float in the wind to reach new areas for germination.
• Animal Dispersal: Some seeds have adaptations that attract animals, which inadvertently transport the seeds to new locations. An example is the burrs of burdock plants that stick to animal fur for dispersal.
• Water Dispersal: Seeds of plants like coconuts and water lilies are designed to float on water, aiding in their dispersal through rivers and oceans to find new suitable locations for growth.
• Explosive Dispersal: Plants like touch-me-nots (Impatiens) have seed pods that burst open upon touch, propelling the seeds away from the parent plant for dispersal.

How Plants Disperse Their Seeds

Plants utilize various methods to spread their seeds:

• Water Dispersal: Plants growing near water bodies like rivers or seas use flowing water to carry their seeds. For instance, coconuts are seeds spread by the sea.
  
• Explosive Mechanisms: Some plants have seed pods that are designed to burst open and propel seeds away from the parent plant. Violets, for example, have exploding seed pods.
  
• Animal Dispersal: Many plants rely on animals to transport their seeds. These seeds may have hooks that attach to an animal's fur. Goosegrass is known to stick to animals and clothing.
  
• Consumption by Animals: Plants produce tasty fruits around their seeds to attract animals. The seeds are dispersed when the animals eat the fruits and excrete the seeds in their droppings. For example, holly seeds have berries that are consumed by birds.
  
• Some seeds are carried by the wind and are designed to float, glide, or spin through the air. For Example, Dandelion seeds are dispersed by the wind.