Changes

==Sex Determination in Birds==

==Sex Determination in Birds==

Birds have sex chromosomes labelled Z and W. The chromosomal requirements for a male in birds is the opposite of that in mammals as the female is the heterogametic species rather than the male. Therefore ZZ results in a male and ZW results in a female.

Birds have sex chromosomes labelled Z and W. The chromosomal requirements for a male bird are the opposite of that in mammals as the female is the heterogametic species rather than the male. Therefore ZZ results in a male and ZW results in a female.

 

==Sex Determination in Reptiles==

==Sex Determination in Reptiles==

Crocodilians, marine turtles, some terrestrial turtles and lizards undergo environmental sex determination. The important factor for sex determination in these species is the incubation temperature of the eggs as this determines the development of the gonads towards testes or ovaries. In crocodiles a higher temperature is male determining whilst in turtles a higher temperature is female determining.

Crocodilians, marine turtles, some terrestrial turtles and lizards undergo environmental sex determination. The important factor for sex determination in these species is the incubation temperature of the eggs as this determines the development of the gonads towards testes or ovaries. In crocodiles a higher temperature is male determining whilst in turtles a higher temperature is female determining.