A non-motile gamete in algae or other organisms, contrasted with a motile zoospore.
From Greek 'a-' (without) + 'planos' (wandering) + 'gamete' (from 'gamos', marriage). A botanical/biological term from 19th-century algology describing reproductive cells.
Some algae make gametes (sex cells) that don't swim—they just sit there and hope a current brings them together, which seems inefficient until you realize it saves massive amounts of energy in calm water.
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