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There were 3 Lifecycle Modification between Ferns and 'osperms.

1. Gametophyte existence became very reduced; tiny germ cells exist only in reproductive tissue.
   Reason:  Diploidy (the presence of extra sets of genes) helped prevent negative mutations due to increased solar radiation.  Haploid germ cells are more likely to be modified by the presence of alleles and there is less investment of resources in this by the plant.

2. Means of fertilization moved from swimming to pollination (dispersion by wind and animal).

3. The seed developed from the spore (resistance to extremes is homologous).

Conifers:  The Largest Gymnosperms.

Adaptations of conifers include a thick cuticle, the needle-shaped leaves, and pitted stomata  Nearly all conifers never lose these needles.  Conifers are heterosporous with a sporophyte developing sporangia in the cones and the gametophyte developing from the haploid cells in the sporangia.  Small pollen cones develop into microspores which develop into pollen grains (immature male germ cells).  Large ovulate cones are always located on a separate branch from the small pollen cones.  These ovulate cones form diploid megaspores which under meiosis to form 4 haploid megaspores (of which only 1 will survive and divide several times to form archegonia complete with its own eggs - quite like human ovum production).  The pollen collects at a site called the mycropyle and germinates while making a path, called the pollen tube, directly to the final megaspore.  Fertilization occurs and the zygote develops into a sporophyte while its container the ovule is being dispersed.  See Top Magnification.

On The Road.  Here is a brief discussion of the evolutionary trends in the gymnosperm classification of plants.

Gymnosperms lacked an chamber, or ovary, for development.  Cycads resemble the angiosperm palm but still bear naked seeds on cone scales.  Ginkgos have fan-shaped leaves that change colors and fall off in the autumn.  Three types of Gnetae exist today:  Weltwitschia has the largest known leaves and exists on in Africa; Gnetum includes tropical trees and vines; and Ephedra is a desert shrub of the western United States.

Next:  "Plants:  Angiosperms."