Seed Plants

• Plants that contain seeds– Gymnosperms – Angiosperms

• Sporophyte dominant

Seed plant spores

• Microspores (male) undergo mitosis to create pollen

• Megaspores (female) undergo mitosis to create egg

Alteration of Generations

Gymnosperms

• Produce “naked seeds” (seeds with no fruit)

• Four groups – Confers, ginkgos, cycads,

gnetophytes• Conifers (pine, spruce,

evergreen) largest group– Specimens today

Gymnosperm life cycle

Male and Female pine cones

Female Male

Angiosperms

• Means “vessel seed”• Plants with seeds, fruits, and

flowers• Reproduction: Double fertilization

– One sperm fertilizes egg (n) other sperm fertilizes n+n (polar nuclei)

– Forms endosperm (3n) nutritive tissue

• Two groups: Monocots and Eudicots

• Monocot: one seed leaf• Eudicot: 2 seed leaves

Flower parts

• Stamen is male, carpel is female• Look at model and dissect live flower

Anther slide

Ovary/ovule slide

Embryo development• Fertilization creates embryo and endosperm

tissue– Endosperm for nutrition

• Enclosed in seed– Monocots have one cotyledon (seed leaf)– Eudocots have two cotyledons

Seedcoat

Endosperm

Cotyledons

Embryo

Fruits• Mature ovary– In terms of botany, peas, tomatoes, and beans are

all fruits, not vegetables• Protects the seed• Helps in seed dispersal

Types of fruits

• Simple: one ovary – Cherry, olive, tomato, grape

• Complex fruits: more than one ovary– Aggregate: Many carpels on a single

flower• Strawberry, raspberry

– Multiple fruit: carpels of many flowers fused together• Pineapple

• Can be fleshy or dry