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
Gymnosperms – lack flowers Angiosperms – flowering plants
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
Only 1 species survives Ginko biloba (maiden hair tree) Either male or female Female trees bear foul-smelling, fleshy seeds
Found in tropical or subtropical climates Large, finely divided leaves Look similar to palms or large ferns Most are approx. 3 feet tall
Male Pollen Cones Female Seed Cone
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
Ephedra Welwitschia mirabilis
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
Flowering plants Dominate earth today Over 260,000 species
Flowers Fruits Broad leaves
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
Ovary surrounding the seed matures into a fruit
Monocots 1 cotyledon Dicots (Eudicots) 2 cotyledon