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The latter has been of more interest and is largely seen as among the reptilian population. TSD mechanisms helps to maintain a balance between the male and the female population i.e. it helps maintain a constant ratio between the genders, which is optimum for the species. Temperature plays a role during the incubation period of the eggs. TSD shows certain patterns when it comes to temperature. In pattern 1a, low temperature gives 100% males and high temperature gives 100% females, in pattern 1b, low temperature gives 100% females and high temperatures gives 100% males while in pattern II low and high temperature yields predominantly females while intermediate temperature yields male population (Pieau et al, p517).
Therefore the theme that comes to mind is the effect that climate change has had or might have on this particular sex determination mechanism. From an ecological point of view human induced disturbances have initiated and accelerated the rate of global warming however the concept of ecosystem and species resilience forms the basis of survival because in spite of the stress and disturbances a species or an ecosystem give rise to functional diversity and response diversity. Even today reptiles are changing their behavioral and nesting patterns to overcome the climatic changes around.
The first reptiles that come to my mind when I think about the theme are the Dinosaurs. However most researchers believe dinosaurs being cold blooded were wiped out as they could not bear the changes in temperature. However according to most recent research it is being said that dinosaurs were hot blooded (Seymour, p1), which means the change in temperature might not have had directly impacted the population therefore I would like to add a different concept connecting sex determination and extinction of all the dinosaur species.
Since it has been proven that most reptiles follow one of the three patterns of temperature dependent sex patterns, it is obvious that dinosaur sex was determined when the egg were in their critical stage during embryonic development of incubation period. One of the key reasons behind Dinosaur extinction in the Cretaceous period must have been changes in the temperature. So there are 2 possibilities that come to my mind. It is obvious that exposure to temperature changes altered the ratio of the male-female population of the dinosaurs and the changes in the nest temperature must have given rise to population of either predominantly male or predominantly female without any balance between the two genders.
Gradually, one of the genders was totally wiped out and the dinosaur population survived as only an all-male population or an all-female population which upsets the developmental biology of that particular species as no offsprings are born. With time the remaining population of the species also died leading to extinction and removal of dinosaurs from the earth. This phenomenon is being seen in painted turtles. Nests of these turtles have been studied and it was seen that the hatchlings were mostly of one gender.
If the current rate of temperature changes continue it is predicted that the turtle species would be wiped out since it would contain only an all-female population. Another line of thought connecting TSD and extinction may also be derived. If climate change produced female dinosaurs and male dinosaurs but the ratio was highly imbalanced intra-specific competition must have set in owing to which many of the competitors perished. Gradual
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