What causes a sea turtle to be born male or female? Environmental Sex Determination. Views Read Edit View history. Washington: Smithsonian Books, Bibcode : Natur. However, there is no evidence thus far that sex ratio is manipulated by parental care.
The thermosensitive, or temperature-sensitive, period TSP is the period during development when sex is irreversibly determined.
In these reptiles, the temperature of the eggs during a certain period of development is the deciding factor in determining sex, and small changes in temperature can cause dramatic changes in the sex ratio Bull Theor Appl Genet — Harrington RW Environmentally controlled induction of primary male gonochorists from eggs of the self-fertilizing hermaphroditic fish, Rivulus marmoratus Poey.
Get the most important science stories of the day, free in your inbox. View Article Google Scholar. Fish Sci Tokyo —
In birds and reptiles, estrogen is essential for ovarian development. Hormones and temperature show signs of acting in the same pathway, in that less hormone is required to produce a sexual shift as the incubation conditions near the pivotal temperature. The temperature of the developing eggs is what decides whether the offspring will be male or female.
Categories : Herpetology Sex-determination systems. Annual Review of Genetics. The thermosensitive, or temperature-sensitive, period TSP is the period during development when sex is irreversibly determined.
Nature has provided many variations on her masterpiece. New Jersey: Pearson Education, In this Page. Other work centers on a theoretical model the Charnov — Bull model ,   predicted that selection should favour TSD over chromosome -based systems when "the developmental environment differentially influences male versus female fitness";  this theoretical model was empirically validated thirty years later  but the generality of this hypothesis in reptiles is questioned.
Sexual differentiation humans Development of the reproductive system gonads Mesonephric duct Paramesonephric duct.