Germ layers

1817 Germ layers

The book of science

Tom Sharp

Heinz Christian Pander embryology Germ layers

Germ layers

Gastrulation of the blastulation


The phrase “ontogeny recaptitulates phylogeny” expresses the idea that the development of embryos repeats the evolutionary stages of the species; however, evolution of a new creature is more interesting than the accumulation of changes to the end of its ancestor’s development. Eggs are single-cells but animal eggs are not the same as single-celled organisms; they contain only half the chromosomes of the mother.

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