Plants rely on their environment to disperse seeds. • Wind • Animal Transport • External • Internal • Other: burying seeds • Drop to ground
Achene Pappus Wind Dispersal Some structures allow seeds to be easily carried in the wind.
Animal Transport Some plants depend upon animals to disperse their seeds. There are three variations of animal dispersal: • External Transport • Examples of seed structures for external transport: • Hooks • Barbs • Internal Transport • Seeds are encased in fleshy fruits • Inadvertent dispersal (burying seeds)
Hooks and Serrated Edges Projections extending from a seed case attach onto a passing animal, carrying the seed to a new location.
Barb Barbs Barbs attach to animal fur.
Internal Dispersal Fleshy fruits surround seeds to be consumed and expelled by animals.
Other Animal Assisted Dispersal The Oak tree depends upon the squirrel for its seed dispersal. Squirrels bury acorns in the Fall and often forget where they are in the winter. These seeds then sprout new trees.
Individual seed Drop Dispersal Some plants simply drop the seeds on the ground. What are some disadvantages of this method?
1 2 3 5 4 What adaptations do seeds have to assist in dispersal? Identify the adaptation and type of dispersal for each of the following pictures.
Answers 1 2 3 5 4 Composite: Pappus; wind Acorn: Food; animal dispersal Wildflower: Drop dispersal Wildflower: Hooks; animal dispersal Composite: Pappus; wind
This is an individual seed case from the burdock bur taken at 60X. Seed photos in this presentation were taken with the QX3 Intel Play Microscope.