Adaptations of Skinks.

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redelapid

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I was looking up some small skinks on the net and came across the South-Eastern Slider (Lerista bougainvillii) and saw that the ones that live on the mainland lay eggs and the ones that are found on the bass strait islands and kangeroo island give birth to live young.

I find this extremly interesting and wonder if this is a example of adaptaion of the species when the islands had not broke of from the mainland and when it did they adapted to survive. Or does this give evidence to evolution.
And i still dont see why they clasify the two a same species? wont they be different as they both have diffrent reproduction means.

Thanks for any replies, Aaron.
 
intersting reproductive biology,to have two different modes in one species,
still does not mean they are different species.
Take the three toed skink Saiphos equalis,they toomvary with different populations being egg laying or live bearing and sometimes a mixture of two.
Sometimes in the same genus species have different modes such as Pseudechis genus,P.porphyriacus is the only live bearer the rest of genus is egg layers.
 
I was going to point out Saiphos as well. Generally in the west they lay eggs and on the coast they give live birth. Same species different mode of reproduciton.
 
Although a Gecko, Binoes are another example with some pops being parthenogenetic.
 
The thing i still dont understand is why they would have different types of reproduction. Why would they have to change?

I think probably (please correct me if wrong) and this is only reffering to the bougainvillii is that the individuals that ended up on the bass starit islands and kangeroo islands had adapted to survive in those windy overcast conditions that islands normally have. So to survive obviously you have to reproduce so i thought in those cold almost "tundra" environments they wouldnt be able to lay thier eggs in a suitable place for incubation so they instead took up giving birth to live young and instead of laying the eggs in an incubation site they get incubated in the lizard so making a mobile egg incubator almost in the lizards belly, because the lizard can move around and bask which heats the eggs.
 
What you just said is a pretty ok overview of the main reasoning behind why some reptiles have live birth and some lay eggs. Now there are of course exceptions but it has been noted that within the same genera often animals further inland in warmer climates lay eggs, and if species occur in the cooler coastal areas they give live birth. As I say there are exceptions but it is the general trend for cooler climate animals to be more successful in live birth than egg laying.
 
Yep got me there, are the parthenogenetic pops sympatric with normal pops?
 
I am not sure but I think some areas they are sympatric and others not. In the east all are sexual as far as I know. It is also not as straight cut as that as even within the sexual and parthenogenic pops there a probably multiple species.
 
The thing i still dont understand is why they would have different types of reproduction. Why would they have to change?

I think probably (please correct me if wrong) and this is only reffering to the bougainvillii is that the individuals that ended up on the bass starit islands and kangeroo islands had adapted to survive in those windy overcast conditions that islands normally have. So to survive obviously you have to reproduce so i thought in those cold almost "tundra" environments they wouldnt be able to lay thier eggs in a suitable place for incubation so they instead took up giving birth to live young and instead of laying the eggs in an incubation site they get incubated in the lizard so making a mobile egg incubator almost in the lizards belly, because the lizard can move around and bask which heats the eggs.


it is intersting,we can speculate and come up with a hypothesis of why this is occurs in a single species,but there could be many reasons,some obvious and some easily overlooked.
 
Hmm sdaj talks about diploid parthenogens being created. I may be wrong but it was always my understanding that the parthenogenesis in bynoei geckos was linked to the triploid genetics. I guess on could experimentally test that as we can experimentally produce triploids one would only need to see if doing so with this gecko also correlated to making parthenogens...
 
Thanks for the information everyone, i am only 14 but i like to look at some rather "interesting" herptological issues such as this and like the endless knowledge you people carry. :)
Would appreciate anymore info on the topic.

Thanks, Aaron
 
See if you can get a copy of Richard Shine's book, Australian Snakes a Natural History. There is plenty of relevant info I'm sure youll find interesting
 
lol, thanks for that advice but ive already read that book but thanks, it is a very good book i found it extremely interesting and when i read it i just couldnt put it down lol.
 
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