Embryology Preformation vs. Epigenesis

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EmbryologyPreformation vs. Epigenesis
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Gametogenesis Fertilization
Nuclei fusion Syngamy - fusion of sperm nucleus
with egg nucleus to form the diploid nucleus.
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Cleavage, Blastula Gastrulation

• Zygote divides mitosis- cleavage, blastula
• By the end of gastrulation - 3 germ layers
• ectoderm
• mesoderm
• endoderm

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• Gastrulation in reptiles, birds, mammals

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Ontogeny recapitulates phylogenyEmbryological
development (ontogeny) involves the same
progression of changes that have occurred during
evolution (phylogeny
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Cloning Nuclear Transfer Blastomere
Separation
Stem Cell ResearchCancerRegeneration