Final answer:
The two tissue layers in Cnidarians are the epidermis and the gastrodermis, with a non-living, jelly-like mesoglea sandwiched in between. Cnidarians, which include jellyfish and corals, are diploblastic and lack complex organs but have specialized cells for various functions.
Step-by-step explanation:
Cnidarians Tissue Layers and Mesoglea
Cnidarians are a group of marine animals that include jellyfish and corals. These organisms exhibit radial symmetry and a simple but effective body structure.
Cnidarians are diploblastic, meaning they are composed of two embryonic germ layers which further develop into two distinct tissue layers.
The outer tissue layer of a cnidarian is the epidermis, while the inner tissue layer, lining the digestive chamber, is called the gastrodermis.
Situated between these two layers is a gelatinous, non-living layer known as mesoglea, which provides structural support and can vary in thickness among different cnidarian species.
Despite the absence of complex organs and organ systems, cnidarians have specialized cells within these tissue layers for various physiological functions.
For instance, nerve cells and nutrient-absorbing cells are prominent, and interlinked by intercellular connections. The nervous system is primitive in cnidarians, characterized by a nerve net that allows for basic responses to environmental stimuli.
These organisms utilize their gastrovascular cavity for both digestion and nutrient distribution, as well as for gas exchange. The mesoglea plays a supportive role and contributes to the cnidarian's hydrostatic skeleton, aiding in movement.