The biggest difference between the fern life cycle and the moss life cycle is the dominant phase: the gametophyte (haploid) is dominant in mosses, while the sporophyte (diploid) is dominant in ferns.
Here's a more detailed breakdown:
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Dominant Generation:
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Mosses: The gametophyte generation is the more conspicuous and long-lived phase. This means the green, leafy part of a moss that you typically see is the haploid gametophyte. The sporophyte grows out of the gametophyte and is dependent on it for nutrition.
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Ferns: The sporophyte generation is dominant. The familiar fern plant with roots, stems, and leaves is the diploid sporophyte. The gametophyte is a small, heart-shaped structure called a prothallus, which is independent but short-lived.
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Dependence:
- Mosses: The sporophyte is nutritionally dependent on the gametophyte.
- Ferns: The gametophyte is independent and produces its own food via photosynthesis (though only for a brief period).
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Visibility:
- Mosses: Gametophyte is the visually obvious and longer living plant.
- Ferns: Sporophyte is the visually obvious and longer living plant.
| Feature | Moss Life Cycle | Fern Life Cycle |
|---|---|---|
| Dominant Phase | Gametophyte (Haploid) | Sporophyte (Diploid) |
| Sporophyte | Dependent on Gametophyte | Independent |
| Gametophyte | Visually obvious and longer living | Small, heart-shaped prothallus, short-lived |
In essence, while both mosses and ferns undergo alternation of generations, the prominence and independence of the gametophyte and sporophyte generations are reversed, representing a key evolutionary difference.
