-
Asked by themarinebiologists to Ailsa, Evan, James, Kath, Ryan on 20 Jun 2011.
-
Evan Keane answered on 20 Jun 2011:
Well what is a “long” or “short” lifespan? We only think a lifespan of 4 days is short because we live for about 80 years but there are other creatures that live for hundreds of years (there are 300 year old tortoises you know!) and some jellyfish which are “immortal”. They would say we have a short lifespan, and other creatures might think 4 days was a lot!
It is an unsolved question as to why we live for as long as we do, and why we age and die at all? It is probably to do with the fact that there is always a younger generation, so if we didn’t die the planet would fill up very quickly and we’d run out of food, water, space etc. Currently we are living much longer than humans have ever done and indeed the population is growing very fast!
-
-
Ryan Ladd answered on 20 Jun 2011:
A lot of animals only really need to stay alive long enough to have babies so, once they’ve done this, there’s not much reason to live any more! There are some insects that only live for a year, spending a lot of that time underground as eggs or larva, only coming to the surface to grow wings, breed and lay eggs, then then die!
I don’t know the exact reason why but I believe there’s a good reason they evolved that way!
As a point of interest, along with Evan’s immortal jellyfish, there is a species of tree call the Bristle Cone Pine which is believed to live forever. The oldest one they’ve ever found was 9000 years old but they only found out after they cut it down and counted the rings!
Comments