The Evolution of Seed Plants

Feb. 18 and 23, 2011 • life cycle of the pines• origin of the seed

Chapter 30

1) origin from ancestors similar to charophytes…

Abies amabilis - Oregon Pinus edulis - New Mexico

Pinus elliottii - Georgia coast Pinus ponderosa - Colorado mts.

Pinus aristata - Colorado Sequoia sempervirens - Calif.

Figure 30.9 The life cycle of a pine (Layer 3)

POLLEN AND SEED CONES OF A PINE

Seed cones

pollen cones

Pollen Cones on a pine tree

Figure 30.10x1 Pine Sporangium with spores

Pine pollen in hand.

dispersed pollen

Male gametophyte growing in nucellus

early pollen

The target of the pollen is the ovule -- near the axis of the seed cone.

Integument

Eggs

Male gametophytes(Megasporangium)

Figure 30.10x3 Pine embryo

Figure 30.9 The life cycle of a pine (Layer 1)

Integument

Figure 30.9 The life cycle of a pine (Layer 2)

Integument

Integument

Figure 30.9 The life cycle of a pine (Layer 3)

Integument

Integument

The Evolution of Seed Plants

• life cycle of the pines• origin of the seed

COAL MEASURE SEQUENCE AT POINT ACONI,CAPE BRETON ISLAND.

COAL

SHALE (MUD STONE) with scattered leaf fossils

SHALE with rootbearing Fossils in place

Seed fern fossils provide cluews to the origin of the seed.

Seed fern fossils provide cluews to the origin of the seed.

Reconstruction of the seed fern Medullosa.

a coal swamp, dominated by spore-dispersed plants

Reconstructions of seed fern seeds

Origin of the Seed. I

Origin of the Seed. II