Alternation of generations : haploid (n) stage that produces gametes followed by diploid
(2n) stage producing spores.
Haploid : gametes; half the number of chromosomes in somatic cell, indicated by n, result of meiosis.
Diploid : somatic cells; double number of chromosomes in gametes, indicated by 2n; result of fertilisation.
Gametophyte : generation producing gametes in gametangium/ gametangia sexual stage.
Sporophyte : generation producing spores in sporangium/ sporangia – asexual stage.
NB: In higher plants the generations alternate in the life cycle of a plant; in lower plants reproduction is either through gametes
(sexual) or spores etc. (asexual).
A haploid gametophyte generation that produces gametes (n) by mitosis ...
the gametes (n) fuse to form zygote (2n), the start of ...
A diploid sporophyte generation that produces spores (n) by meiosis.
Ferns (Pterophyta/ Pteridophyta)
Seed plants (Spermatophyta)
Gymnospermae (cone-bearing plants producing seeds)
Angiospermae (flowering plants producing seeds)
Exam guidelines require study of mosses and flowering plants to highlight alternation of generations.
Leaf-like structures of moss gametophyte
Sporangium of moss sporophyte
Fern leaf (sporophyte) with sori (groups of sporangia
Female cones at different ages Male cones
Ferns, gymnosperms and flowering plants