4. The Rise and Fall of Dinosaurs
• Dinosaurs are found in the
fossil record starting about
230 million years ago.
• The last dinosaurs bcame
extinct about 65 million
years ago.
• Impact Hypothesis: A
10km-wide meteorite had
smashed into the Yucatan
peninsula in Mexico,
causing worldwide forest
fires, tsunamis several
kilometres high, and an
'impact winter'
5. The Rise and Fall of Dinosaurs
• Evidence prior to impact
that diversity of dinosaur
species was on the
decline.
• Climate change?
• Rise of Angiosperms?
– Sometime in the Mid-
Cretaceous Period; between
144 to 65 Million Years
Ago
– Corresponds with a decline
of the gymnosperms and
rise of animal groups
8. Some Example Stories:
Perfect Flowers: Pea exclusively self-pollinating
Hibiscus self-pollinating if not crossed
Cherry self-incompatible only outcrosses
Imperfect Flowers: Begonia unisexual but monoecious
Holly unisexual and dioecious
Variable: Cucumber male, perfect, female, parthenocarpic
13. Symmetry: *=radial †=bilateral
Flower Formula: Symbol Sequence to Diagram Flower
Number of Parts per Whorl:
• sepals in calyx
Fusion within whorl:
curved line over number
Fusion between whorls:
square bracket below numbers
Attachment of flower parts relative to ovary:
horizontal line
*
* 5, 5, , 5
* 5,
* 5, 5, ,
* 5, 5,
• petals in corolla
• stamens in androecium
• carpels in gynoecium
