Plant groups and alternation of generations – life-cycle wheel
BiologyPlant PhysiologyAges 16–17
Loading…
Sign in to play
Compare algae, mosses, ferns, conifers and flowering plants by vascular tissue, roots, seeds, flowers and fruit on labelled drawings, then follow each group's life cycle on an animated wheel: haploid (n) and diploid (2n) stages, where meiosis and fertilisation happen and whether the gametophyte or the sporophyte dominates. Spirogyra (haplontic) and humans (diplontic) complete the comparison.
Lesson: Plant kingdom: algae, bryophytes, pteridophytes, gymnosperms and angiosperms; alternation of generations
What it shows
Plants are grouped by a few key features: vascular tissue (xylem and phloem) appears in ferns, seeds in gymnosperms, and flowers and fruits in angiosperms. All land plants alternate between a haploid gametophyte, which makes gametes by mitosis, and a diploid sporophyte, which makes spores by meiosis. In mosses the gametophyte dominates; in ferns, conifers and flowering plants the sporophyte does, and in seed plants the gametophyte shrinks to a few cells. Meiosis halves the chromosome number and fertilisation restores it, so it stays constant from one generation to the next.
How to use
Start on Plant groups: tap a group in the top strip or a row of the table and read the labelled drawing. Then open Life cycle, pick a Group and press Run to travel round the wheel, or Step from stage to stage; the panel shows how meiosis and fertilisation change n and 2n. Under Tasks, press Order the cycle to test yourself and answer the chromosome question with Check.
Parameters you can change
- View Plant groups, Life cycle
- Group Algae, Mosses, Ferns, Conifers, Flowering plants, Human
- Animation speed 0.25–2 ×
- Show labels
Questions to explore
- Why do mosses stay small and grow in damp places, while ferns can grow taller?
- In which stage does meiosis happen in a fern, and in which in Spirogyra?
- How do meiosis and fertilisation keep the chromosome number of a species constant?
