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Kil
Evil Skeptic
USA
13476 Posts |
 Posted - 11/28/2010 : 14:20:59
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This is cool. And it looks like the evolution of egg laying to live birth in reptiles is not as complicated as it was once thought to be...
Evolution in Action: Lizard Moving From Eggs to Live Birth
Evolution has been caught in the act, according to scientists who are decoding how a species of Australian lizard is abandoning egg-laying in favor of live birth.
Along the warm coastal lowlands of New South Wales (map), the yellow-bellied three-toed skink lays eggs to reproduce. But individuals of the same species living in the state's higher, colder mountains are almost all giving birth to live young.
Only two other modern reptiles—another skink species and a European lizard—use both types of reproduction. (Related: "Virgin Birth Expected at Christmas—By Komodo Dragon.")
Evolutionary records shows that nearly a hundred reptile lineages have independently made the transition from egg-laying to live birth in the past, and today about 20 percent of all living snakes and lizards give birth to live young only.
(See "Oldest Live-Birth Fossil Found; Fish Had Umbilical Cord.")
But modern reptiles that have live young provide only a single snapshot on a long evolutionary time line, said study co-author James Stewart, a biologist at East Tennessee State University. The dual behavior of the yellow-bellied three-toed skink therefore offers scientists a rare opportunity.
"By studying differences among populations that are in different stages of this process, you can begin to put together what looks like the transition from one [birth style] to the other." |
Read on...
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Uncertainty may make you uncomfortable. Certainty makes you ridiculous.
Why not question something for a change?
Genetic Literacy Project |
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The Rat
SFN Regular
Canada
1370 Posts |
 Posted - 11/28/2010 : 14:37:38 [Permalink]
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Cool stuff, and I fearlessly predict that creationists will be thoroughly unimpressed. But screw 'em.
Originally posted by Kil
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Am I the only one thinking 'Jabba the Hutt after a diet'? 
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Bailey's second law; There is no relationship between the three virtues of intelligence, education, and wisdom.
You fiend! Never have I encountered such corrupt and foul-minded perversity! Have you ever considered a career in the Church? - The Bishop of Bath and Wells, Blackadder II
Baculum's page: http://www.bebo.com/Profile.jsp?MemberId=3947338590 |
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Lizard Moving From Eggs to Live Birth
