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 following points highlight the two types of eggs. The types are: 1. Eggs Based on Quantity of Yolk 2. Eggs Based on Distribution of Yolk in Cytoplasm. Type # 1. Eggs Based on Quantity of Yolk: 1. Microlecithal Eggs: They contain very small amount of yolk, e.g. eggs of Sea urchin, Herdmania, amphioxus. The eggs of man contain very [...]
In this article we will discuss about the Structure of a Typical Fish. Fishes are cold blooded animals, typically with backbone, gills and fins. The body of a typical fish comprises the head, trunk and tail. The head bears two eyes, with well developed nictitating membrane, two internal ears, two nostrils which are closed internally (except in lung fishes) and [...]