Evolution in Action: Lizard Moving From Eggs to Live Birth

[Corey]

Scoobes said:

Corey said:

Isn't evolution based around survival of the fittest where members of a species born with certain beneficial genetic traits are more likely to survive and reproduce carrying on those traits to their offspring, which over time continues to completely change animals.

Maybe I'm missing something here but I Question how such a change occurs where they can transition from laying eggs to live birth, this didn't happen overnight obviously but how did the traits of transitioning to live birth before live birth was possible benefit the lizards so they could pass on such a gene?

It looks like this might be associated with epigenetics. Under certain conditions, chemical modifications can up or down regulate and even shut-off certain genes. I doubt that they've developed a gene specifically for live birth. More likely the genes for associated with laying eggs have been suspended due to temperature (note that without studying the DNA of these genes it's impossible to say for sure) causing them to live birth. As long as the offsping are still viable then it's a form of adaptation.

These epigenetic changes can become permanent and be passed on to offspring too so could potentially lead to a branch of lizards that only live-birth.

Very interesting, thanks for clearing that up