Gemmules

Definition

Gemmules are asexual reproductive structures produced by certain sponges. They are composed of a group of archaeocytes surrounded by a protective coat made of spicules and spongin.

5 Must Know Facts For Your Next Test

1. Gemmules help sponges survive in unfavorable environmental conditions, such as extreme cold or drought.
2. They contain totipotent cells called archaeocytes that can develop into a new sponge when conditions improve.
3. The protective coat of gemmules is made from silica or calcium carbonate spicules and spongin fibers.
4. Gemmulation is a key survival strategy for freshwater sponges but can also occur in some marine species.
5. When conditions become favorable, the archaeocytes exit the gemmule and differentiate to form a new sponge.

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Related terms

Archaeocytes: Totipotent cells within a sponge that can differentiate into various cell types.

Spicules: Structural elements found in most sponges, made of silica or calcium carbonate.

Spongin: A protein fiber that provides flexibility and structural support to the sponge's body.