Overviews of critical period concepts, as they appear at several biological levels, are presented. in embryology, critical periods generally refer to restricted periods in development during which undifferentiated groups of cells can be induced to differentiate. in neurobiology, critical periods are those during which neural circuits are particularly plastic and subject to molding by cellular processes and by experience. Look for a groove on the surface of the developing egg over the microscope glass slide in the later stages of development. This groove is the neural tube. This will eventually develop into a spinal cord, the characteristic that associates the frog with other vertebrate animals. Though not without some attendant difficulties, it is a worthwhile project to try raising some eggs to the tadpole period and thence to maturity. The metamorphosis of a frog is one of the natures greatest lessons seen only under a microscope. The book will be proved to be a boon for the readers, students as well as teachers. Contents: Genetics Embryology and Fishes; Embryonic Development: Getting Started; Gross Morphologic Overview of Upper Limb Development . Fish Anatomy; Facultative Parthenogenesis in Vertebrates: Reproductive Error or Chance?; The Early Development of Vertebrates; Development of the Eggs and Early Larvae of Six California Fishes.
