The study of the human body involves anatomy, physiology, histology and embryology. Two-photon microscopy has been involved with numerous fields including&colon; physiology, neurobiology, embryology and tissue engineering. By 1858 he was serving as professor of physiology, general anatomy and embryology. Charaka contributions to the fields of physiology, etiology and embryology have been recognised. Crow particularly delighted in being able to teach embryology and comparative anatomy. Therefore, the study of invertebrate embryology has advanced the study of vertebrate embryology. At Bryn Mawr, she expanded the fields of genetics, cytology, and embryology. A revised version was later published in "Italian Journal of Anatomy and Embryology". Women also found opportunities in botany and embryology. Many principles of embryology apply to invertebrates as well as to vertebrates. Evolutionary embryology is the expansion of comparative embryology by the ideas of Charles Darwin. Medical embryology is used widely to detect abnormalities before birth. Many erroneous theories were formed in the early years of comparative embryology. Frogs are used in cloning research and other branches of embryology. Baer was a naturalist, biologist, geologist, meteorologist, geographer, and a founding father of embryology.