Sexual Reproduction in Flowering Plants

Visit: http://koning.ecsu.ctstateu.edu/Plants_Human/lecppt/flower.ppt

Alternation of Generations in Plants

Life Cycle of a Typical Animal

Life Cycle of a Typical Plant

Flowers and Fossils

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'

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

Why Dinosaurs Went Extinct!

The Far Side by Gary Larson.

Basic Flower Structure

stigma

style

ovary

locule

ovule

carpelgynoecium

pollen

anther

filament stamenandroecium

petal

corolla

perianthsepalcalyx

receptacle

pedicelPerianth is complete

Flower is perfectFlower is monoecious

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

Basic Flower Structure

stigma

style

ovary

locule

ovule

carpelgynoecium

pollen

anther

filament stamenandroecium

petal

corolla

perianthsepalcalyx

receptacle

pedicelPerianth is complete

Flower is perfectFlower is monoecious

superior

Flower is hypogynous

Pistil is simple

Ovary SuperiorFlower Hypogynous

Flower Perigynous

Flower EpigynousOvary Inferior

Ovary Half-Superior

Ovary Half-Inferior

Ranunculus acris - buttercupFlower Structure - review

Basic Flower Structure

stigma

style

ovary

locule

ovule

carpelgynoecium

pollen

anther

filament stamenandroecium

petal

corolla

perianthsepalcalyx

receptacle

pedicelPerianth is complete

Flower is perfectFlower is monoecious

superior

Flower is hypogynous

Pistil is simple

This longitudinal section view does not allow us to consider symmetry

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

Ovary SuperiorFlower Hypogynous

Flower Perigynous

Flower EpigynousOvary Inferior

Ovary Half-Superior

Ovary Half-Inferior

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