. Advanced biology. Biology; Physiology; Reproduction. The parthenogenetic frogs produced experimentally by Jacques Loeb resembled normal frogs in their ap- Spring and summer aphids or plant lice are wingless females which pro- duce young, parthenogenetically, e very lo to 20 days. In the autumn, males are produced, mating occurs, and fer- tilized eggs are laid which last over the winter and hatch into females the fol- lowing spring. suits in the possibility of slight or great differences among offspring. Parthenogenesis. It has been stated that the entrance of a sperm into an egg s
. Advanced biology. Biology; Physiology; Reproduction. The parthenogenetic frogs produced experimentally by Jacques Loeb resembled normal frogs in their ap- Spring and summer aphids or plant lice are wingless females which pro- duce young, parthenogenetically, e very lo to 20 days. In the autumn, males are produced, mating occurs, and fer- tilized eggs are laid which last over the winter and hatch into females the fol- lowing spring. suits in the possibility of slight or great differences among offspring. Parthenogenesis. It has been stated that the entrance of a sperm into an egg stimulates a chemical change in the membrane which seals the micropyle, and stimulates the egg to go through repeated divisions. The late Jacques Loeb, formerly at the Rockefeller Insti- tute, carried on a series of experiments to investigate the nature of the fertili- zation process. He pricked the eggs of sea urchins with an electric needle and found that this brought about a membrane activity and the egg began to cleave. He next found that certain chemicals caused the same results. This process of the development of the egg without the entrance of a sperm. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Wheat, Frank Merrill; Fitzpatrick, Elizabeth T. New York ; Boston [etc. ] : American Book Company
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Keywords: ., bookcentury1900, bookdecade1920, booksubje, booksubjectphysiology
