What is the Difference Between Telolecithal and Centrolecithal Egg?

The main difference between telolecithal and centrolecithal eggs lies in the distribution of yolk within the egg's cytoplasm.

• Telolecithal Egg: In telolecithal eggs, the yolk is unevenly distributed throughout the cytoplasm, with a higher concentration towards the vegetal pole. Animals that lay telolecithal eggs include birds, reptiles, and fish.
• Centrolecithal Egg: In centrolecithal eggs, the yolk is concentrated in the center of the ovum cytoplasm, and the cytoplasm is restricted to a thin peripheral layer. Arthropoda animals lay centrolecithal eggs. In centrolecithal eggs, most of the yolk is liquid, but a solid part can also be observed, known as the yolk sphere. During the cleavage step, centrolecithal eggs undergo superficial cleavage, which is limited to the thin cytoplasm layer.

In summary, telolecithal eggs have an uneven distribution of yolk throughout the cytoplasm, while centrolecithal eggs have the yolk concentrated at the center of the cytoplasm.

Comparative Table: Telolecithal vs Centrolecithal Egg

The main difference between telolecithal and centrolecithal eggs lies in the distribution of yolk within the egg. Here is a table comparing the two types of eggs:

Both telolecithal and centrolecithal cells undergo meroblastic cleavage, with cleavage being limited to the thin cytoplasm layer in centrolecithal eggs.