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 [...]
The below mentioned article provides biology notes on Phylum Hemichordata. (Gk. hemi- half, chordate- notochord) Due to some similarities with chordates, some workers considered Hemichordata as a subphylum under phylum chordata. But, on grounds of its general organization, recent scientists, like Vander Horst (1939), Dawyd off (1948), Marcus (1958) and Hyman (1959), have given it the status of a phylum [...]
In this article we will discuss about:- 1. Levels of Organisation Found in Animals 2. Body Plans of Animals. Levels of Organisation Found in Animals: 1. Protoplasmic or Acellular Level: The organisation is at the level of protoplasm. It is present in protozoans. 2. Cellular Level: The body consists of many cells which may be similar or show minor division [...]