Thursday, October 25, 2012

Evolution
The long-living clams!

Yes, clams are among the oldest living animals, and many of them have been observed to have crossed the age of 400 years.
In 2007, a team of scientists from Bangor University's School of Ocean Sciences reportedly discovered a quahog clam, Arctica islandica, which was living and growing on the seabed in the cold waters off the north coast of Iceland for around 400 years, wh
ile other recent reports suggest that some clams can live longer than 500 years.
What's amazing is that these clams continue to pass on their genes even at 200 or 300 years, while they have very less to fear from predators given their hard shells. And herein may lie the secret of their longevity.
Longevity is a very complex but important issue in Evolution, and it has lots to do with the chances of an animal being eaten. The hard shell of these clams protect them from most predators, so it makes sense for them to spend resources in extending their longevity and reproduce when time and conditions seem fit. Contrast this with a salmon, for which it makes much sense to spend most of its resources in reproduction and not for longevity as it's much more vulnerable to being eaten compared to a clam.

Source:
1) (around 24:00) http://www.youtube.com/watch?v=kEclvp40KHU
2) http://www.sciencedaily.com/releases/2007/10/071028100032.htm
3) http://news.nationalgeographic.com/news/2007/10/071029-oldest-clam.html
4) http://news.bbc.co.uk/2/hi/science/nature/7066389.stm

Image credit:
http://www.sciencebuzz.org/sites/default/files/images/quahog.jpg
The long-living clams!

Yes, clams are among the oldest living animals, and many of them have been observed to have crossed the age of 400 years. 
In 2007, a team of scientists from Bangor University's School of Ocean Sciences reportedly discovered a quahog clam, Arctica islandica, which was living and growing on the seabed in the cold waters off the north coast of Iceland for around 400 years, while other recent reports suggest that some clams can live longer than 500 years. 
What's amazing is that these clams continue to pass on their genes even at 200 or 300 years, while they have very less to fear from predators given their hard shells. And herein may lie the secret of their longevity.
Longevity is a very complex but important issue in Evolution, and it has lots to do with the chances of an animal being eaten. The hard shell of these clams protect them from most predators, so it makes sense for them to spend resources in extending their longevity and reproduce when time and conditions seem fit. Contrast this with a salmon, for which it makes much sense to spend most of its resources in reproduction and not for longevity as it's much more vulnerable to being eaten compared to a clam. 

Source:
1) (around 24:00) http://www.youtube.com/watch?v=kEclvp40KHU
2) http://www.sciencedaily.com/releases/2007/10/071028100032.htm
3) http://news.nationalgeographic.com/news/2007/10/071029-oldest-clam.html
4) http://news.bbc.co.uk/2/hi/science/nature/7066389.stm

Image credit: 
http://www.sciencebuzz.org/sites/default/files/images/quahog.jpg

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