The following points highlight the two types of germinal layers of the animals. The types are: 1. Segmentation 2. Development. Germinal Layers: Type # 1. Segmentation: Segmentation is division or differentiation of the body into distinct portions called segments. It is of two types: metameric segmentation and pseudo-metamerism. I. Metameric Segmentation (True metamerism or True segmentation): It is a type [...]
The upcoming discussion will update you about the differences between Fishes and Tetrapoda. Difference # Fishes: 1. Fishes have paired appendages in the form of pectoral and pelvic fins. 2. Fishes respire by means of gills. 3. Except lung fishes they do not have internal nares. 4. Heart is 2 chambered except lung fishes where heart is 3 chambered. 5. [...]
The upcoming discussion will update you about the differences between Cartilaginous and Bony Fishes. Difference # Cartilaginous Fishes: 1. Cartilaginous fishes are mostly marine. 2. The mouth of cartilaginous fishes is ventral. 3. The external nares are ventral. 4. The scales of cartilaginous fishes are Placoid. 5. In cartilaginous fishes, operculum is absent except chimaera. 6. Caudal fins are heterocercal [...]