Metabolic Disorder - Theory to Relate Extinction of Dinosaurs
There are a number of theories pertaining to the extinction of Dinosaurs from the Earth. However, a famous theory states that a metabolic disorder caused the thinning of the egg shells during the incubation period which resulted due to changes in the hormone of the dinosaurs. The embryos died as the egg shells were unable to protect them from predation as well as dehydration. Thus, the infant’s death would have resulted in the wiping out of the whole population of dinosaurs. The other reason which resulted in the pathological condition of the shell was the formation of bi or multi shells which resulted in the embryo dying due to suffocation.
The homologous phenomena of egg formation in bird and reptiles have been used to formulate this theory. It was concluded that pathological eggs were produced due to hormonal imbalance of the vasotocin and estrogen levels. Also the formation of teratological shell repetition resulted in embryo suffocation and since the thickness of the egg shell thinned, it caused the breakage of the shell resulting in embryo dehydration. The lethality of the egg shell thinning is attributed to the absence of a “resorption craters” in the mammillary knobs in them. This absence may have caused in them the failure to fertilize the egg or the embryo perished before the calcification of their skeletal bones.
The change in the environmental condition and climate is considered the sole reason why hormonal imbalance happened in dinosaurs which resulted in their extinction. The study on the egg shell composition of the dinosaurs using isotopic calibration of carbonates and oxygen values suggested some of these views when there was a slight change in the temperature from higher to lower degree or a change of climate from dry to humid condition.