In this article we will discuss about the analysis of nature and action of organizer in amphibian eggs. Grey crescent—its Role in Development: Wilhelm Roux (1888) first described the grey crescent in amphibian egg. The experiments of Rund and Spemann have emphasised the vital role of grey crescent in amphibian development (see Fig. 5.14). If the egg is surgically divided [...]
In this article we will discuss about:- 1. Meaning of Cleavage 2. Planes of Cleavage 3. Types 4. Effects of Yolk 5. Mechanism 6. Chemical Changes 7. Different Chordates 8. Importance in Embryonic Pattern. Contents: Meaning of Cleavage Planes of Cleavage Types of Cleavage Effects of Yolk in Cleavage Mechanism of Cleavage Chemical Changes during Cleavage Cleavage in Different Chordates [...]
In this article we will discuss about:- 1. Movements of Body Parts in Living Organism 2. Types of Movement in Living Organism. Movements of Body Parts in Living Organism: All the animals are able to move their body parts. (a) Movements of External Body Parts: These serve many purposes: (i) Movements of limbs, appendages, head and trunk help to maintain [...]