Seeds What terrestrial adaptations led to the success of seed plants? Gametophyte generation is even more reduced! Why hasn’t the gametophyte generation been erased? Allele screening can occur in gametophytes since they are haploid Sporophyte embryos depend on female gametophyte for food Ones with the best alleles will survive
Spores in brypohytes and mosses resist environmental changes Seeds replace spore’s role of dispersing the species. Spores are retained within the sporangia Pollen frees sperm from water
Gymnosperms What does gymnospem mean? Naked seeds How are the needle shaped leaves of Coniferophyta adapted to dry conditions? Thicker cuticle, stomata in pits
Coniferophyta Examples…
Sequoia Douglas Fir Juniper Cypress
Pine ovulate cone ovules
Ovule from ovulate cone
Pine staminate cone Pollen Pollen sac
Germinating pollen grains
Seed Dispersal in Coniferophyta
Hypothetical phylogeny of Seed Plants