YEAR 5 CHAPTER 4 Seed Dispersal

You find a seed stuck to your sock after walking through a forest. It is small, light, and has tiny hooks. Which conclusion is MOST accurate about how this seed is dispersed?

• It depends on wind to fly away

• It likely explodes from its pod

• It sticks to animals or humans for dispersal

• It floats on water for long distances

A scientist removes the tiny hooks from burr seeds. Predict two likely effects on the plant population over time.

• Seeds cannot attach to animals, reducing dispersal range; fewer new plants grow in other areas.

• Seeds become heavier and explode forcefully, spreading farther.

• Animals prefer eating hookless seeds, increasing dispersal via digestion.

• Seeds float better in water, allowing new habitats to be colonized.

Compare dandelion and lotus seed. What makes their dispersal method different?

• Dandelion is carried by wind; lotus floats on water

• Dandelion explodes; lotus is eaten by animals

• Dandelion is sticky; lotus has hooks

• Dandelion is heavy; lotus is light and hairy

Why would a rubber seed growing directly under the rubber tree likely fail to become a tall tree?

• It would explode due to crowding

• It lacks DNA to grow

• It would compete with the parent plant for sunlight and nutrients

• It would be eaten by the same animal that ate the parent

You observe a plant with dry, tightly closed pods that suddenly burst open on a hot day. What condition triggered seed dispersal and what method is used?

• Wind, by winged seeds

• Rain, by water dispersal

• Heat, by explosive mechanism

• Animal, by juicy fruit

Which of the following shows a misconception about dispersal?

• "Only animals help spread seeds."

• "Coconut floats because it has air cavities."

• "Papaya seeds are excreted after animals eat them."

• "Cotton seeds are light and can fly with the wind."

Imagine you're designing a new fruit to disperse by wind. Which feature would you AVOID including?

• Long, thin wings

• Lightweight structure

• Juicy and fragrant flesh

• Fine hairs around seed

If sea levels rise and flood more land areas, which seed type would MOST likely benefit from this environmental change?

• Explosive

• Wind-dispersed

• Animal-dispersed

• Water-dispersed

A fruit has both waxy skin and hooks. What is the MOST likely primary dispersal method, and why?

• Wind, because hooks help it fly

• Explosive, because waxy skin makes it burst

• Water, because waxy skin helps it float

• Animal, because hooks attach to fur despite waxy skin

Which strategy BEST increases a plant’s survival rate over generations?

• Producing large seeds that drop near the plant

• Having seeds with no special structures

• Dispersing seeds widely using multiple methods

• Releasing seeds only when animals pass by