当前位置:首页 >> 生命科学 >> 生态与保护生物学
没有了生存竞争,生物进化更快?

一只毒蛙正在保护它的卵(图)

由加拿大麦克马斯特大学的Ben Evans带领的科研小组证实了,在菲律宾附近的苏拉威西岛上一种新型有毒的蛙类正在飞速的进化。

该小组在岛上发现了13种有毒的蛙类,其中有9种在之前从未发现过。这些种类按体型的大小、蹼的数量、甚至是它们哺育后代的方式来划分——所有的特征都与它们所处的不同生态位的需求相符。苏拉威西岛现在拥有和菲律宾群岛相同数量的有毒蛙类。

Evans说道:“因为菲律宾群岛面积如此之大,我们本来期望能够找到更多的种类,但情况却不是那样。”

为什么在一个小岛上能有如此的生物多样性呢?研究者们认为是由于苏拉威西岛的竞争压力较小。在菲律宾群岛上的毒蛙类和另一种蛙类Playmantis存在生存斗争。而苏拉威西岛却不存在这种蛙类,使得岛上的有毒蛙类自由的分布在岛上各个不同的栖息地,并且最终适应那里的环境。这些快速进化的蛙类是对达尔文著名的适应辐射理论的一个不小的冲击。

英文论文摘要:

Adaptive Radiation and Ecological Opportunity in Sulawesi and Philippine Fanged Frog (Limnonectes) Communities.

Because island communities are derived from mainland communities, they are often less diverse by comparison. However, reduced complexity of island communities can also present ecological opportunities. For example, amphibian diversity on Sulawesi Island is lower than it is in the Philippines, but Sulawesi supports a surprising diversity of Sulawesi fanged frogs (Limnonectes). Here we examine molecular, morphological, and geographical variation of fanged frogs from these two regions. Using genealogical concordance, morphology, and a Bayesian approach to species delimitation, we identified 13 species on Sulawesi, only four of which have been previously described. After evolutionary history is accounted for, a model with multiple body size optima in sympatric species is favored over a “random-walk” model of body size evolution. Additionally, morphological variation is higher among sympatric than nonsympatric species on Sulawesi but not in the Philippines. These findings suggest that adaptive radiation of fanged frogs on Sulawesi was driven by natural selection to infiltrate ecological niches occupied by other frog lineages in the Philippines. This supports a role of ecological opportunity in community assembly: diversification in mature communities, such as the Philippines, is limited by a dearth of unoccupied ecological niches. On Sulawesi, evolutionary novelties originated in a predictable and replicated fashion in response to opportunities presented by a depauperate ancestral community.

 

分享按钮
评论:   
验证码:  
  [Ctrl+Enter]
相关文章
摘要
关键字
生物进化
 
 
最新推荐文章


近期热点新闻