Hundreds of new frog species found in Madagascar

[spark03]

http://www.cnn.com/2009/TECH/science/05/06/eco.madagascar.frogs/index.html?imw=Y&iref=mpstoryemail

I'd like to say that I'm a firm believer in evolution. I read this article and it brought up a reoccurring question that I think about regarding evolution.

"A study identified between 129 and 221 new species of frogs on the island (Madagascar)." I understand that certain variations in genes in animals will increase rate of survival. This gets passed onto offspring, and so on. Examples like the peppered moth makes perfect sense to me. On the other hand, I don't understand how 175 (average) species of frogs can evolve on a remote island like Madagascar, and these remember are "new" or newly found species. I'm sure there are several climate, and terrain zones on the island that can account for some diversity, but I would think you'd find a bunch of frog species in one environment with the same predators, terrain, food source etc. What do you think caused all the diversion of species? To me, it would seem interbreeding would be inevitable in such close quarters and would be difficult to force a split of species.

 

[Möbiµs]

It makes perfect sense to me that these frogs could thrive in that environment. The only reason I could think of for these sudden discoveries is that the area might not have been explored thoroughly before.

 

[Homunclus]

Out of the top of my head I can think of a number of reasons to account for such diversity. First of all rainforests are amongst the worlds most rich places (as far as biodiversity is concerned). I believe this is due to the fact the environment is very stable witch gives more time for variation to occur and for more extremely specialized creatures to occupy very specific ecological niches.

That said it is important to point out that Madagascar, despite being an island, is huge and at the same time it is not really that isolated since it is relatively close to the continent. Both factors lead to an increase on biodiversity.

 

[ebbixx]

That said it is important to point out that Madagascar, despite being an island, is huge and at the same time it is not really that isolated since it is relatively close to the continent. Both factors lead to an increase on biodiversity.

Relatively close? Assuming you could maintain a straight path, the shortest hop from continental Africa to Madagascar is over 260 miles (420 km). And the nearest island hops in between are about 170 miles (270 km or roughly 160,000 smoots )

I'd actually say that, besides the climate, the island's relative isolation, especially from large predators, is one of the main reasons for the diversity. You're right about the landmass though, that's another major factor. Similar diversity can be found in the Malaysia-Indonesia-New Guinea island chain, probably for similar reasons.

Being relatively undeveloped by humans may also be a major factor, considering the drastic die-off among amphibians in recent years in most of the "developed" areas of the world.