Summary
The plant life cycle alternates between a haploid gametophyte and a diploid sporophyte.
In depth
Mosses: the gametophyte is dominant. Ferns: both are independent, sporophyte dominant. Seed plants: the gametophyte is tiny and dependent (pollen grain, embryo sac).
Gametophytes make gametes by mitosis; sporophytes make spores by meiosis. In flowering plants the male gametophyte is the pollen grain and the female gametophyte is the embryo sac.
Key idea: the diploid sporophyte dominates in ferns and seed plants, the haploid gametophyte in mosses.
Frequently asked questions
What is Alternation of Generations?
The plant life cycle alternates between a haploid gametophyte and a diploid sporophyte.
Which area of biology covers Alternation of Generations, and how advanced is it?
Alternation of Generations is one of the 56 topics in Plant Biology. It is rated Intermediate, so it suits learners who already know the core vocabulary. Related topics in this area include Plant Kingdom, Double Fertilisation, Plant Phylogeny.
Can you give an example of Alternation of Generations?
Fern spores develop into a small heart-shaped prothallus.
What should I learn before Alternation of Generations?
Work through the Beginner topics in Plant Biology first, such as Plant Kingdom, Photosynthesis, Chlorophyll, then return to Alternation of Generations. Intermediate topics assume the Beginner vocabulary.
What topics are related to Alternation of Generations?
The closest topics to Alternation of Generations are Plant Kingdom, Double Fertilisation, Plant Phylogeny, Rubisco. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Alternation of Generations?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Alternation of Generations. To practise the whole of Plant Biology, use the Plant Biology quiz.
How is Alternation of Generations different from Plant Kingdom?
Alternation of Generations: The plant life cycle alternates between a haploid gametophyte and a diploid sporophyte. Plant Kingdom: Multicellular, mostly photosynthetic eukaryotes with cellulose walls, from mosses to flowering plants. Read both side by side and note what each one explains.
How should I study Alternation of Generations step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Plant Kingdom and explain the difference aloud. Finally, take the Plant Biology quiz and come back to this page for any question you miss.