What would happen if every baby born was a girl?
You don’t have to be an evolutionary biologist to know things wouldn’t look good for the species.
That was the scenario many thought reptiles could face under climate change – until research from Macquarie University provided some reassuring results.
Gender in many reptile species is influenced by ambient temperature while the embryo is maturing, a process known at temperature-dependent sex determination or TSD.
Warmer temperatures tend to result in more female hatchlings so the fear was global warming would create a lack of male individuals, eventually leading to unsustainable breeding populations and mass extinction.
Luckily though, a study of freshwater turtles conducted partially at Macquarie University shows temperature is not the only factor.
In fact, embryos themselves can influence their gender by moving inside the egg.
It seems eggs laid on a slight angle within a nest vary in temperature from one end to the other.
Embryos can shift towards either the warm or the cold end, changing how they develop.
Researcher Rick Shine says the discovery is good news for ecological diversity and may also explain why some reptile species have been around so long.
“Reconstruction of the ancestral lineages of many TSD species shows that they have survived for millions of years, including during periods where the average temperatures were much hotter than current climate change models predict,” Professor Shine says.
“It’s encouraging to know that turtles may be better than we expected at dealing with some of the challenges wrought by climate change.”
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