The external genitalia consist of all the external reproductive structures. Anatomical terminology [ edit on Wikidata ]. In males, the gonads are the testes and in females they are the ovaries. Bibcode : SciA In many animals, differences in the exposure of a fetal brain to sex hormones are correlated with significant differences of brain structure and function, which correlate with adult reproductive behavior.
Genetic Sex Differentiation in Fish. Testosterone will also control the descending of the testes from the abdomen into the scrotom.
This increase in aromatase enables individuals to develop into males or females depending on the temperatures experienced. Parthenogenesis is a type of asexual reproduction in which a female how does sex determination occur in reptiles in Peterborough or egg cell develops into an individual without fertilization.
Berlin: Springer-Verlag, In an interesting twist, some organisms that reproduce by parthenogenesis actually need sexual activity for parthenogenesis to occur. Another example in which sex determination is affected by the location of the organism is the case of the slipper snail Crepidula fornicata.
The estrogen synthesis inhibitors used in the experiments mentioned above worked by blocking the aromatase enzyme, showing that experimentally low aromatase conditions yield male offspring. Environmental sex determination in reptiles: ecology, evolution, and experimental design.
In the late s, James J. Journal of Systematics and Evolution.
Download as PDF Printable version. Washington, D. This includes both internal and external genital differentiation.
Scientific Reports. Sex portal. Over the next five weeks, the fetus begins producing hormones that cause its sex organs to grow into either male or female organs. Further sex differentiation of the external genitalia occurs at puberty , when androgen levels again become disparate.
The presence of the SRY gene on the Y chromosome causes the development of the testes in males, and the subsequent release of hormones which cause the paramesonephric ducts to regress.