Extinction hits 'whole families' (BBC)

By Victoria Gill
Science reporter, BBC News

Whole "chunks of life" are lost in extinction events, as related species vanish together, say scientists.

A study in the journal Science shows that extinctions tend to "cluster" on evolutionary lineages - wiping out species with a common ancestor.

The finding is based on an examination of past extinctions, but could help current conservation efforts.

Researchers say that this phenomenon can result in the loss of an entire branch of the "tree of life".

The message for modern conservation, say the authors, is that some groups are more vulnerable to extinction than others, and the focus should be on the lineages most at risk.
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more: http://news.bbc.co.uk/2/hi/science/nature/8188166.stm