2. Pollination Occurs when pollen reaches the stigma
2 types—cross-pollination and self-pollination
Cross-pollination—pollination by a different individual
Self-pollination—pollination by the same individual
Self-pollination has similar results as asexual reproduction
Cross-pollination is similar to reproduction in animals, in that it:
insures the mixing of genetic material
insures genetic diversity

3. Mechanisms to Insure Cross-pollination
Stamen and Style mature at different times
Stigma and pollen are incompatible— stigma prevents pollen growth if it’s from the same plant
Monoecious and Dioecious species
Monoecious (“one house”) —male / female flowers on the same plant
Example = corn
Dioecious (“two houses”) —male / female flowers on different plants
Example = dates, willows

4. Animals and Pollination
Wind pollination is inefficient and “expensive”
Angiosperms and insects begin association 120 mya
Angiosperms and Insects evolved together—co-evolution
Plants developed flowers that attracted pollinators
Insects developed body parts to reach nectar
Some flowers developed bilateral symmetry to match the pollinator
Co-evolution also occurred with birds and bats
Some bizarre adaptations for pollination can be found at:
Other animals can also pollinate:
Birds, bats, etc.

5. Some plants developed to protect the ovary from damage by animals.
The bases of the stamens, petals and sepals fuse around the ovary, and the “flower” begins above the ovary.
This is an “inferior ovary”
Some did not develop this way, and the ovary is above the petals, sepals and stamens.
This is a “superior ovary”.

6. How fertilization happens (angiosperms)
Pollen arrives on the stigma
Pollen begins to grow into the pistil
This creates a “pollen tube” that reaches the ovary
The gametes move down this tube
Gametes fuse with the ova to form a zygote
The zygote develops into seed that will grow into the sporophyte

7. Seed Dispersal (and examples) —the “big 5!”
Wind (Dandelion)
Water (Coconut palm)
Thrown from the parent plant (Poppy)
Attaches to an animal and is carried away (Beggars Lice, Cockle bur)
Eaten by animals and deposited elsewhere (Apple)

8. Fruit Development
Ovary develops into a fruit that contains the seed(s)
Flower parts may persist (apple) or die and fall off (orange)
Fruits have 3 distinct layers
Exocarp—outermost layer (skin or peel)
Mesocarp—middle layer (flesh)
Endocarp—inner layer (pit or stone)
Pericarp = exocarp + mesocarp + endocarp

9. FRUIT TYPES FLESHY FRUITS
Berry—all 3 layers (exocarp, mesocarp, endocarp) are soft
Grape, Tomato
Pome—similar to berry, but endocarp is papery or leathery
Apple
Drupe—similar to berry, but endocarp is hard
Peach, Cherry, Plum
Pepo—fleshy but the exocarp is a tough, hard rind; inner tissues may not be distinguishable
Pumpkin, Squash
Hesperidium—exocarp is leathery
Orange, lemon, lime

10. Dry Fruits Indehiscent (not opening up at maturity)
Caryposis—small, simple. Seed coat fused to fruit
Grasses: rice, oats, wheat, corn
Achene—like caryopsis, but seed and fruit are distinct. Fruit wall is papery
Sunflower
Samara—one seed fruit with wing like outgrowths
Maple, ash, alder
Nut—pericarp is hard
Walnut, pecan, almond
Dehiscent (does open up at maturity)
Legume—fruit breaks along both sides
Beans, peas
Follicle—fruit breaks open on one side
Columbine, milkweed
Capsule—opens many ways
Primrose, poppy, iris

11. Compound Fruits
Aggregate fruit—carpels of flower NOT fused but grow together during fruit maturation
Raspberry, blackberry
Multiple fruit—all the fruits grow together during maturations
pineapple