Comparing plant life cycles
≈ 48 minComparing plant life cycles
Plants alternate between a haploid gametophyte stage, which produces gametes, and a diploid sporophyte stage, which produces spores. In mosses the gametophyte is conspicuous and fertilisation requires water. In ferns the sporophyte dominates but the small gametophyte still needs water. In seed plants the gametophyte is greatly reduced and protected inside pollen and ovules. Comparing life cycles reveals how reproduction became less dependent on wet conditions.
Work it through
A fern spore grows into a small gametophyte. It makes gametes, and water allows sperm to reach an egg. A pine instead delivers male gametes in pollen, protecting the process from dependence on puddles.
Mastery target
Compare which generation is dominant and whether water is needed for fertilisation in two plant groups.
Which plant group has reproduction least dependent on external water for fertilisation?
Name the key biological term from Comparing plant life cycles: enter the term that best fits the explanation and visual model.
A plant has spores and a visible leafy gametophyte. Which group is it most likely to resemble?
Which statement corrects a common misunderstanding in Comparing plant life cycles?