Gymnosperms: “naked seeds” Cycadophyta Ginkophyta Coniferaphyta Gnetophyta

Seed plant recap: derived traits Reduced—microscopic—gametophytes Protected within sporophyte Dependent on sporophyte for nutrients Heterospory different male and female reproductive structures Ovules (develops into seed) Pollen (containing sperm) Protection of gametophyte from environment Protects sperm and allows fertilization w/o water Protects and enhances embryo survival

Gymnosperm Origins Fossil evidence for seedplants 360 m.y.a. Among the Carboniferous forests of seedless vascular plants Fossil evidence of extant Gymnosperms ~ 305 m.y.a. Drying climate 299-251 m.y.a. created environment where seedplants had an adaptive advantage proliferation of gymnosperms Extant Angiosperms arose 200 m.y. after extant gymnosperms

Gymnosperm diversity 4 taxa Cycadophyta Ginkophyta Gnetophyta Coniferaphyta – primary model

Cycadophyta (cycads) Very prolific in Carboniferous period Flagellated sperm w/ in pollen tube Palm like w/ stroboli (cones) 200+ species Highly threatened today

Ginkophyta (Ginkos) Flagellated sperm w/ in pollen tube Deciduous Looses leaves Separate male and female plants (dioecious) Females produce a fleshy seed that is stinky and undesirable…vomit like 1 species (not found in wild) Long lived (up to 2500 yrs)

Gnetophyta Non-flagellated sperm Usually dioecious Similarities w/ angiosperms Has vessel members Double fertilization ~70 species Welwitschia

Distribution of Gnetophyta genera gnetum ephedra welwitschia

Coniferaphyta (Conifers): pines, firs, cedars, junipers, spruces, etc.

Coniferous forest dominated regions of world

Conifers ~600 species Mostly Northern Hemisphere—high latitudes & high altitudes/elevations Non-flagellated sperm Mostly Evergreen Needle like or scale like leaves Clusters of needles organized by fascicles Cold Adapted Many are mycorrhizal dependent Commercially important Lumber/timber-- Softwood (no fibers and thin tracheid walls) Paper/wood pulp Pine tar Resin turpentine

Southern Hemisphere Conifers

Pine Needle

Pine Needle

Cones = stroboli Most plants are monecious Separate male and female cones

Male Cones & Pollen Formation

Pine Seeds: mostly winged some wingless varieties (birds, pine nuts Pine Seeds: mostly winged some wingless varieties (birds, pine nuts..yum)