SeedsSeeds What terrestrial adaptations led to the

success of seed plants? Gametophyte generation is even more r

educed!

What terrestrial adaptations led to the success of seed plants?

Gametophyte generation is even more reduced!

First seed plantsFirst seed plants Gymnosperm: conifers

vascular heterospory

male vs. female gametophytes seeds

naked seeds (no fruit) pollen

contain male gametophyte life cycle dominated by sporophyte stage

coniferous trees you are familiar with are diploid

reduced (microscopic) gametophyte reduction of gametophyte protects delicate egg

& embryo in protective sporophyte protected from drought & UV radiation

Gymnosperm: conifers vascular heterospory

male vs. female gametophytes seeds

naked seeds (no fruit) pollen

contain male gametophyte life cycle dominated by sporophyte stage

coniferous trees you are familiar with are diploid

reduced (microscopic) gametophyte reduction of gametophyte protects delicate egg

& embryo in protective sporophyte protected from drought & UV radiation

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

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

GymnospermsGymnosperms

What does gymnospem mean?Naked seedsHow are the needle shaped leaves of

Coniferophyta adapted to dry conditions?

Thicker cuticle, stomata in pits

What does gymnospem mean?Naked seedsHow are the needle shaped leaves of

Coniferophyta adapted to dry conditions?

Thicker cuticle, stomata in pits

Coniferophyta Examples…Coniferophyta Examples…

Gymnosperm: conifers Gymnosperm: conifers

Cones & naked seeds Cones & naked seeds

malemale

femalefemale

male (pollen) cones

female cones

sporangium & pollen

pine embryo

PollenPollen

Pollen eliminated the requirement for water for fertilizationspread

through wind & animal

Pollen eliminated the requirement for water for fertilizationspread

through wind & animal

Pine ovulate cone

ovules

Ovule from ovulate cone

Mature Ovule Just Before Fertilization

Mature Ovule Just Before Fertilization

FertilizationFertilization

FertilizationFertilization

Pine staminate cone

Pollen

Pollen sac

Pollen grains

Germinating pollen grains

Seed Dispersal in Coniferophyta

Seed Dispersal in Coniferophyta

Hypothetical

phylogeny of Seed Plants

Hypothetical

phylogeny of Seed Plants