BIOA02H3 Lecture Notes - Lecture 6: Seed Dispersal, Impatiens, Inbreeding Depression
BIOA02 Module 1 Lecture 6: From Seed to Tree
Problem
Without seed dispersal adaptations, most seeds are deposited close to mother plant
Parent-offspring competition for space
Mating between closely related individuals: inbreeding depression
o Less fit and healthy offspring
For animals, they are mobile and shouldn’t be a problem
For plants, they have ingenious adaptations
Different Dispersal Agents
Explosive self-dispersal DIY: ballistochory (1 meter)
Wind dispersal (1-60 mteters)
Water dispersal (1000 kilometers)
External hitchhiking (less than 15 meters)
Internal hitchhiking (several kilometers, up to 100kilometers)
Ant dispersal (1-5 meters)
Gravity: barochory and secondary dispersal by animals
Ballistochory DIY
e.g. Jewelweed (Touch-me-not)
Anemochory
Hairs help the seed stay in the air
Parachutes are branched with fine fluffy hair
Winged Maples
Size and angle of the wings must be right to twirl it around
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BIOA02H3 Full Course Notes
Verified Note
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Document Summary
Bioa02 module 1 lecture 6: from seed to tree. Without seed dispersal adaptations, most seeds are deposited close to mother plant. Mating between closely related individuals: inbreeding depression: less fit and healthy offspring. For animals, they are mobile and shouldn(cid:3244)t be a problem. Hairs help the seed stay in the air. Size and angle of the wings must be right to twirl it around. Weight of the seed affects it as well. Exozoochory: hooks, barbs e. g. burdock arctium minus gets attached to animals and hitches onto the outside of animal. Endozoochory e. g. berries, cherry animals eat the food and travels inside of animal. Myrmecochory elaiosomes (elaios- oil, some-body) fleshy structure attached to seeds. Rich in lipids and proteins symbolic relationship: plant seed dispersal; ant food. Seed anatomy (angiosperms) contains plant embryo, covered with protective seed coat (test) embryo: embryonic shoot, root (radicle) and cotyledons (embryonic leaves) food for embryo (endosperm) (food for disperser: endosperm surrounds embryo.
