EVERYDAY SCIENCE

Detailed explanation-1: -They are non-motile, or capable of only limited movement along a substrate by secretion of mucilaginous material along a slit-like groove or channel called a raphe.

Detailed explanation-2: -Pinnularia is an ecologically important and species-rich genus of freshwater diatoms (Bacillariophyceae) showing considerable variation in frustule morphology. Interspecific evolutionary relationships were inferred for 36 Pinnularia taxa using a five-locus dataset.

Detailed explanation-3: -Some pennate diatoms are capable of a type of locomotion called “gliding", which allows them to move across surfaces via adhesive mucilage secreted through a seamlike structure called the raphe. In order for a diatom cell to glide, it must have a solid substrate for the mucilage to adhere to.