Planarianët

Planarianët are a class of free-living flatworms belonging to the phylum Platyhelminthes. They are characterized by their flattened bodies, which can range in size from a few millimeters to several centimeters. Planarianët are found in both freshwater and marine environments, as well as in terrestrial habitats, often under rocks, logs, or leaf litter. They are predatory or scavengers, feeding on small invertebrates, dead organic matter, and other small organisms. A notable feature of planarianët is their remarkable regenerative ability. If a planarian is cut into pieces, each fragment can regenerate into a complete, new individual. This regeneration is not limited to just physical damage; it can also occur under specific experimental conditions, making them a significant model organism in scientific research, particularly in studies of stem cells and regeneration. They possess a simple nervous system with a brain-like structure called a cephalic ganglion and a ladder-like nerve cord system. Many planarianët have two eyespots, which can detect light intensity and direction but do not form images. Their locomotion is achieved through the use of cilia on their ventral surface and muscular contractions. Reproduction in planarianët can be asexual, through fission, or sexual, as they are hermaphroditic, possessing both male and female reproductive organs.