Seedless Plants – Whisk Ferns

Seedless plants - Ferns Most diverse of group In tropics, grow very tall Haploid spores produced in sporangia which

form on special leaves of the sporophyte Spores dispersed by wind Give rise to tiny haploid gametophyte

plants, which produce sperm and eggs As in bryophytes, gametophytes lack

conducting vessels and the sperm must swim through water

Fern Diversity

Fern Life Cycle: Woodwardia

Seed plants Produce pollen and seeds Pollen are tiny structures that carry

sperm producing cells Dispersed by wind of animal pollinators

(i.e. bees) Sperm travel through air to fertilize egg

cells Seeds consist of an embryonic plant,

a supply of food for the embryo, and a protective outer seed coat Can remain dormant until suitable

habitat is available Male gametophyte is the pollen grain Female gametophyte produces the

egg

2 types of seed plants Gymnosperms – lack flowers Angiosperms – flowering plants

Seed plants - Gymnosperms

Evolved earlier than flowering plants Were dominant until the rise of flowering

plants Most early species are now extinct 4 phyla

Ginkgos Cycads Gnetophytes Conifers

Seed plants – Gymnosperms - Ginkgos

Only 1 species survives Ginko biloba (maiden hair tree)

Either male or female Female trees bear foul-

smelling, fleshy seeds Maintained by cultivation More resistant to pollution

than other trees Leaves used as herbal

remedy for improving memory

Seed plants – gymnospermsCycads

Found in tropical or subtropical climates

Large, finely divided leaves

Look similar to palms or large ferns

Most are approx. 3 feet tall

Seed plants – gymnospermsGnetophytes

Include approx. 70 species of shrubs, vines, and small trees

Genus Ephedra contains compound that is a stimulant and appetite suppressant Reports of deaths

Welwitschia mirabilis – dry deserts of Africa Deep taproot can extend up to 100 ft down into

the soil Has fibrous stem with only 2 leaves Leaves never shed and continue to grow Oldest plants are more than 200 yrs old

Gnetophytes

Ephedra

Welwitschia mirabilis

Seed plants – gymnospermsConifers

Still dominant plant Species include pines, firs, spruce,

hemlocks, cypresses Most abundant in cold latitudes and high

elevations Adapted to cold, dry conditions

Retain green leaves, can continue photosynthesis

Leaves are thin needles covered with a thick, waterproof surface that minimizes evaporation

Produce “antifreeze” in their sap (gives piney scent) Can continue transporting nutrients in below-freezing

temperatures

Conifer Life Cycle: Ponderosa Pine

Seed plants - Angiosperms Flowering plants Dominate earth today Over 260,000 species

3 major adaptations of angiosperms

Flowers Fruits Broad leaves

Flowers Both male and female gametes are formed May have evolved when ancient

gymnosperm developed relationships with animals (i.e. insects) that carried pollen from plant to plant

Flower Structure

Why fruits?

Ovary surrounding the seed matures into a fruit

Many fruits entice animals to disperse seeds

Some hitchhike on animals Some fruits have special structures to aid

dispersal (i.e. maple fruits form wings that carry seed)

Broad leaves

Life Cycle: Lilium

Flower Plants – 2 Groups Monocots

1 cotyledon Dicots (Eudicots)

2 cotyledon