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Lecture 21

BIOL 1902 Lecture Notes - Lecture 21: Cardiac Glycoside, Fagus Grandifolia, Umbel

Course Code
BIOL 1902
Michael Runtz

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BIOL 1902 – Week 21
Getting progeny off to a good start in life:
-Parental Care in animals
oIn the care of parents until ready to start own life
-Seed Dispersal in plants
Seed must be protected before dispersal:
-Armour = hard seed coats (physical protection)
oE.g., Scaly cones, acorns, Beaked Hazel, American Beech
- Seeds can be protected chemically
oUnripe berries protected w/ bitter terpenoids
oAposematic colouration
oYoung cones full of resin (terpenoids)
oMilkweed seeds well protected by pod full of cardiac glycosides (terpenoids)
How are seeds sent off?
- Plants in open, sunny habitats, such as old fields, often use the wind
oWind dispersal called anemochory
oE.g. Dandelion
oSmall, lightweight seeds
oSilk parachutes
- No solution = perfect; drawback of wind:
oToo much wind
oMissing target habitat, such as waters
Compensate by producing lots of seeds
Each Fireweed flower produces 70 000 – 100 000 seeds
-Hooks & barbs catch on hair or feathers
oSeeds hitch-hike; stick-tight
-Burdock seeds also hitch-hike
-Queen Anne’s Lace also uses animal power for seed dispersal, but not every day
oUmbel closes on cloudy days – why?
oOpens on sunny days
- Dispersal via animals = zoochory (can happen on inside or outside of animals)
Seeds travel inside animals:
- E.g. bears feed on blueberries – seeds come out in droppings
oWaxwings eat fruit & poop out seeds
-Seed Dispersers
oWaxwings exploited as seed dispersers
-Seed Predators
oE.g. Chipmunks – they want hard, inside of berry
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