Become familiar with each of these trends and the example organisms. Nervous and muscle tissue Glycogen as carbohydrate reserve Sexual reproduction is common Embryo is layered through cleavage and gastrulation. Lining the spongocoel are flagellated choanocytes that generate water current and trap food particles. The body consists of two layers of cells separated by a gelatinous region called the mesohyl. Amoebocytes wander through the mesohyl, take up food, digesting it and carrying the nutrients to other cells.
Most sponges are hermaphrodites.
In all animals except the sponges, the embryo structure develops from specific layers called germ layers that appear through a process called gastrulation. A diploblastic organism has only and ecto- and endoderm. A triploblastic organism has all three germ layers. Organisms with radial symmetry are diploblastic and have a circular arrangement of body parts with only an oral side and an aboral side. These organisms are basically a sac with a central digestive compartment called the gastrovascular cavity .