Telomerase Immortality

[mage lang=”en|es|fr|en” source=”flickr”]telomerase immortality[/mage]
Have evolution select species to die sooner?

Species on this planet have evolved with immune systems to fight of all the diseases so individuals can live long enough to procreate. However, as far as i know all of the species have evolved to actually die so when the cell devide, the telomerase get short so eventually species die so why have evolution selected against immortality if its so advantageous. Or, is evolution INCOMPLETE?

Species have NOT evolved to die. The more accurate phrasing is that they have not evolved to live indefinately. After reproduction, and the passing on of genetic material, Selection can no longer exert any pressure on a population. This means that a species cannot evolve a longer life span unless there is some environmental pressure which causes reproduction to occur later, thereby selecting those individuals who can both survive, and remain fertile until such a time. Actually, since reproduction is the defining event, some think that populations may actually enrich with genes which cause enhanced function in early life, but are detrimental later, eg. increased calcium deposition in bones. Its called antagonistic pleiotropy.

Recent research on yeast has found genes which are regulated by metabolism, and can sense a dearth of nutrition. When they do, they cause changes which allow the yeast to extend both their life and fertility until conditions improve. So you can see that there are some ways in which selection can yield a longer life span.