Reproduction’s Basic Features
The following are some of the essential characteristics shared by all ways of reproduction:
1. RNA and Protein Synthesis
2. DNA replication
3. Cell division
4. Reproductive units
5. The maturation of reproductive units into youngones
1. Gametogenesis i.e. Formation of Gametes: Spermatozoa and Ova
2. Fertilization i.e. Conception is the union of male and female gametes to generate a zygote.
3. Gestation i.e. development events from conception till the birth of the youngone, also termed pregnancy. From the commencement of the last menstrual cycle, it takes roughly 280 days. Duration of pregnancy varies in different animals. Three sequential processes occur in pregnancy
1. Cleavage (Segmentation) and Blastulation i.e.rapid divisions of the zygote to form a multicellular body (ball or disc) of cells called blastomeres.
2. Gastrulation i.e Cells travel to generate germ layers.
3. Organogenesis is the differentiation of cells in the germ layers to produce tissues, organs, and organ systems.
4. Parturition i.e. Birth of full-term youngone.
Differentiation is again in complexity and structure, while growth is an increase in size.