Why the tropics have more species than the poles of the Earth

the tropics have more species because of the more humid enviroments because not many warm blooded animals can live near the poles. because of the abnormally cold temperatures, not many animals can survive unlike in tropical areas where there is a more vaste amounts of food and plant species, also shelter.

tsd is temerature dependent sex determination.

tsd: it is a type of environmental sex determination in which the temperature experienced during embryonic/ larval development (ambient temperature for development) determine the sex of the offspring.

crocodile displays the tsd where the ambient temperature of the developing egg determines the individual's sex. for example in the american alligator's eggs, incubation at 33 ºc produces mostly males, while incubation at 30 ºc produces mostly females. so if the american alligator's egg will get the ambient temperature (33 degree celcius)during embryonic development from egg, the offspring will be male and same for the female sex determination.