1. The Gymnosperms pp

2. Phylum Tracheophyta Vascular plants Three major classes:
Class Filicineae - the ferns
Class Gymnospermae - plants which bear seeds not enclosed in an ovary
Class Angiospermae - plants which bear seeds enclosed in an ovary (flowering plants)

3. The Gymnosperms “gymno” = naked “sperm” = seed
Seeds are exposed on scales of a cone

4. Adaptations to very cold & very dry climates:
Alternation of generations
Haploid gametophyte dependent on diploid sporophyte
So, gametophytes do NOT require moist environments to survive or reproduce!!

5. Needles Modified leaves Have less surface area Have waxy cuticle
So, are more resistant to water loss!

6. Pollen (male gametophyte)
Do NOT require water to travel
Are carried by wind to female gametophyte
So, is adapted to dry conditions!

7. Seeds Can become dormant if conditions are not favourable
Provides food supply for developing embryo
Has protective seed coat (protects embryo)

8. Vascular tissue (xylem & phloem)
Conducts water & nutrients to different parts of the plant
Helps strengthen the stem

9. Gymnosperm Reproduction
“Pine Tree” (sporophyte) produce male & female cones
In the ovule, a megaspore parent cell produces megaspores.
In the pollen sacs, microspore parent cells produce pollen grains (microspores)
One megaspore becomes the female gametophyte.
Mature pollen grains are the male gametophyte.

10. Sperm from male gametophyte (pollen) fertilizes the egg in the female gametophyte via a pollen tube.
Ovule develops into a seed which contains the embryo.
Seed falls off the female cone & develops into a tree.