MadSci Network: General Biology |
Yes, both bacteria and some fungi move, but they do so in very different ways. Motion can occur either by swimming, sliding, or by cell changing shape. In many fungi you can see rivers of cytoplasm (the jelly-like material inside of cells) moving through a long filament of inter-connected cells. This is called cytoplasmic streaming, and is visible under a microscope in several types of bread mold. Bacteria can either swim (some have dozens of flagellae, singular: flagellum), propelled by tiny rotating corkscrews, rather like a boat propellor. Others slide by secreting tiny streams of a mucus or slime material out through very tiny pores. Many bacteria do not move at all. Fungi, such as mushrooms, can grow through the soil from a single spot and spread over several acres of land, in essense growing into a gigantic fairy ring; (most of their "body" is composed of tiny hairlike threads (ususally yellow or white) that can be easly seen in the upper few inches of ground, especially in a forest with lots of dead leaves on the ground. The threads themselves do not move from side to side, but they can grow forward by dividing and elongating their cells. One species can actually move suddenly: they form microscopic loops, like wire snares used to trap rabbits. The two or three cells that make up the loop can suddenly swell up with water when touched by a tiny worm (called a nematode). If the worm had accidently stuck its head into the loop, it will suddenly become hopelessly trapped, and soon gets eaten by threads that grow out from the loop cells into the body of the worm. Because mushrooms themselves don't move, some attact insects to them by smelling like rotten meat or by glowing in the dark. The insect comes and has a meal, eating hundreds of reproductive spores that are then carried to new places when the insect flies away. Pretty clever! So, many types of bacteria and some fungi do move, but many species do not have to actively move at all, provided that they receive a steady supply of food (dissolved amino acids or dead leaves, etc.) to replenish what they consume.
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