Chapter 43.2, Problem 2R

Summary Introduction

To review:

The cleavage role by genes in the development is expressed in mammals but not in the frogs and sea urchins.

Introduction:

The phenomenon of cleavage in animals results in the multicellularity of the organism. The fusion of the male and the female gamete results in the formation of the single-celled zygote. The cleavage refers to the cell divisions that turn the diploid single-celled zygote into a mass of cells that are undifferentiated, which grows into an embryo. These cell divisions are not accompanied by the cell growth.